1463 lines
41 KiB
C
1463 lines
41 KiB
C
/******************************************************************************
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*
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* Back-end of the driver for virtual block devices. This portion of the
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* driver exports a 'unified' block-device interface that can be accessed
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* by any operating system that implements a compatible front end. A
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* reference front-end implementation can be found in:
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* drivers/block/xen-blkfront.c
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*
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* Copyright (c) 2003-2004, Keir Fraser & Steve Hand
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* Copyright (c) 2005, Christopher Clark
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#define pr_fmt(fmt) "xen-blkback: " fmt
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#include <linux/spinlock.h>
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#include <linux/kthread.h>
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#include <linux/list.h>
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#include <linux/delay.h>
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#include <linux/freezer.h>
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#include <linux/bitmap.h>
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#include <xen/events.h>
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#include <xen/page.h>
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#include <xen/xen.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/hypercall.h>
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#include <xen/balloon.h>
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#include <xen/grant_table.h>
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#include "common.h"
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/*
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* Maximum number of unused free pages to keep in the internal buffer.
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* Setting this to a value too low will reduce memory used in each backend,
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* but can have a performance penalty.
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*
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* A sane value is xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST, but can
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* be set to a lower value that might degrade performance on some intensive
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* IO workloads.
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*/
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static int max_buffer_pages = 1024;
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module_param_named(max_buffer_pages, max_buffer_pages, int, 0644);
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MODULE_PARM_DESC(max_buffer_pages,
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"Maximum number of free pages to keep in each block backend buffer");
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/*
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* Maximum number of grants to map persistently in blkback. For maximum
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* performance this should be the total numbers of grants that can be used
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* to fill the ring, but since this might become too high, specially with
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* the use of indirect descriptors, we set it to a value that provides good
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* performance without using too much memory.
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*
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* When the list of persistent grants is full we clean it up using a LRU
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* algorithm.
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*/
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static int max_pgrants = 1056;
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module_param_named(max_persistent_grants, max_pgrants, int, 0644);
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MODULE_PARM_DESC(max_persistent_grants,
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"Maximum number of grants to map persistently");
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/*
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* How long a persistent grant is allowed to remain allocated without being in
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* use. The time is in seconds, 0 means indefinitely long.
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*/
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static unsigned int pgrant_timeout = 60;
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module_param_named(persistent_grant_unused_seconds, pgrant_timeout,
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uint, 0644);
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MODULE_PARM_DESC(persistent_grant_unused_seconds,
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"Time in seconds an unused persistent grant is allowed to "
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"remain allocated. Default is 60, 0 means unlimited.");
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/*
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* Maximum number of rings/queues blkback supports, allow as many queues as there
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* are CPUs if user has not specified a value.
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*/
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unsigned int xenblk_max_queues;
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module_param_named(max_queues, xenblk_max_queues, uint, 0644);
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MODULE_PARM_DESC(max_queues,
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"Maximum number of hardware queues per virtual disk." \
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"By default it is the number of online CPUs.");
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/*
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* Maximum order of pages to be used for the shared ring between front and
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* backend, 4KB page granularity is used.
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*/
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unsigned int xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
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module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, 0444);
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MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
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/*
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* The LRU mechanism to clean the lists of persistent grants needs to
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* be executed periodically. The time interval between consecutive executions
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* of the purge mechanism is set in ms.
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*/
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#define LRU_INTERVAL 100
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/*
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* When the persistent grants list is full we will remove unused grants
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* from the list. The percent number of grants to be removed at each LRU
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* execution.
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*/
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#define LRU_PERCENT_CLEAN 5
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/* Run-time switchable: /sys/module/blkback/parameters/ */
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static unsigned int log_stats;
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module_param(log_stats, int, 0644);
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#define BLKBACK_INVALID_HANDLE (~0)
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static inline bool persistent_gnt_timeout(struct persistent_gnt *persistent_gnt)
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{
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return pgrant_timeout && (jiffies - persistent_gnt->last_used >=
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HZ * pgrant_timeout);
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}
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#define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
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static int do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags);
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static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
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struct blkif_request *req,
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struct pending_req *pending_req);
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static void make_response(struct xen_blkif_ring *ring, u64 id,
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unsigned short op, int st);
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#define foreach_grant_safe(pos, n, rbtree, node) \
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for ((pos) = container_of(rb_first((rbtree)), typeof(*(pos)), node), \
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(n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL; \
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&(pos)->node != NULL; \
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(pos) = container_of(n, typeof(*(pos)), node), \
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(n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL)
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/*
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* We don't need locking around the persistent grant helpers
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* because blkback uses a single-thread for each backend, so we
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* can be sure that this functions will never be called recursively.
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*
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* The only exception to that is put_persistent_grant, that can be called
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* from interrupt context (by xen_blkbk_unmap), so we have to use atomic
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* bit operations to modify the flags of a persistent grant and to count
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* the number of used grants.
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*/
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static int add_persistent_gnt(struct xen_blkif_ring *ring,
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struct persistent_gnt *persistent_gnt)
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{
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struct rb_node **new = NULL, *parent = NULL;
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struct persistent_gnt *this;
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struct xen_blkif *blkif = ring->blkif;
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if (ring->persistent_gnt_c >= max_pgrants) {
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if (!blkif->vbd.overflow_max_grants)
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blkif->vbd.overflow_max_grants = 1;
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return -EBUSY;
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}
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/* Figure out where to put new node */
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new = &ring->persistent_gnts.rb_node;
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while (*new) {
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this = container_of(*new, struct persistent_gnt, node);
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parent = *new;
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if (persistent_gnt->gnt < this->gnt)
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new = &((*new)->rb_left);
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else if (persistent_gnt->gnt > this->gnt)
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new = &((*new)->rb_right);
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else {
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pr_alert_ratelimited("trying to add a gref that's already in the tree\n");
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return -EINVAL;
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}
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}
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persistent_gnt->active = true;
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/* Add new node and rebalance tree. */
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rb_link_node(&(persistent_gnt->node), parent, new);
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rb_insert_color(&(persistent_gnt->node), &ring->persistent_gnts);
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ring->persistent_gnt_c++;
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atomic_inc(&ring->persistent_gnt_in_use);
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return 0;
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}
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static struct persistent_gnt *get_persistent_gnt(struct xen_blkif_ring *ring,
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grant_ref_t gref)
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{
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struct persistent_gnt *data;
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struct rb_node *node = NULL;
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node = ring->persistent_gnts.rb_node;
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while (node) {
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data = container_of(node, struct persistent_gnt, node);
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if (gref < data->gnt)
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node = node->rb_left;
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else if (gref > data->gnt)
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node = node->rb_right;
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else {
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if (data->active) {
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pr_alert_ratelimited("requesting a grant already in use\n");
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return NULL;
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}
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data->active = true;
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atomic_inc(&ring->persistent_gnt_in_use);
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return data;
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}
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}
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return NULL;
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}
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static void put_persistent_gnt(struct xen_blkif_ring *ring,
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struct persistent_gnt *persistent_gnt)
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{
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if (!persistent_gnt->active)
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pr_alert_ratelimited("freeing a grant already unused\n");
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persistent_gnt->last_used = jiffies;
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persistent_gnt->active = false;
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atomic_dec(&ring->persistent_gnt_in_use);
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}
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static void free_persistent_gnts(struct xen_blkif_ring *ring, struct rb_root *root,
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unsigned int num)
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{
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struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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struct persistent_gnt *persistent_gnt;
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struct rb_node *n;
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int segs_to_unmap = 0;
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struct gntab_unmap_queue_data unmap_data;
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unmap_data.pages = pages;
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unmap_data.unmap_ops = unmap;
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unmap_data.kunmap_ops = NULL;
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foreach_grant_safe(persistent_gnt, n, root, node) {
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BUG_ON(persistent_gnt->handle ==
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BLKBACK_INVALID_HANDLE);
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gnttab_set_unmap_op(&unmap[segs_to_unmap],
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(unsigned long) pfn_to_kaddr(page_to_pfn(
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persistent_gnt->page)),
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GNTMAP_host_map,
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persistent_gnt->handle);
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pages[segs_to_unmap] = persistent_gnt->page;
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if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
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!rb_next(&persistent_gnt->node)) {
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unmap_data.count = segs_to_unmap;
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BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
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gnttab_page_cache_put(&ring->free_pages, pages,
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segs_to_unmap);
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segs_to_unmap = 0;
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}
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rb_erase(&persistent_gnt->node, root);
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kfree(persistent_gnt);
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num--;
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}
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BUG_ON(num != 0);
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}
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void xen_blkbk_unmap_purged_grants(struct work_struct *work)
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{
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struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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struct persistent_gnt *persistent_gnt;
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int segs_to_unmap = 0;
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struct xen_blkif_ring *ring = container_of(work, typeof(*ring), persistent_purge_work);
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struct gntab_unmap_queue_data unmap_data;
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unmap_data.pages = pages;
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unmap_data.unmap_ops = unmap;
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unmap_data.kunmap_ops = NULL;
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while(!list_empty(&ring->persistent_purge_list)) {
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persistent_gnt = list_first_entry(&ring->persistent_purge_list,
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struct persistent_gnt,
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remove_node);
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list_del(&persistent_gnt->remove_node);
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gnttab_set_unmap_op(&unmap[segs_to_unmap],
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vaddr(persistent_gnt->page),
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GNTMAP_host_map,
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persistent_gnt->handle);
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pages[segs_to_unmap] = persistent_gnt->page;
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if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
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unmap_data.count = segs_to_unmap;
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BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
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gnttab_page_cache_put(&ring->free_pages, pages,
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segs_to_unmap);
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segs_to_unmap = 0;
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}
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kfree(persistent_gnt);
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}
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if (segs_to_unmap > 0) {
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unmap_data.count = segs_to_unmap;
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BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
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gnttab_page_cache_put(&ring->free_pages, pages, segs_to_unmap);
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}
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}
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static void purge_persistent_gnt(struct xen_blkif_ring *ring)
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{
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struct persistent_gnt *persistent_gnt;
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struct rb_node *n;
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unsigned int num_clean, total;
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bool scan_used = false;
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struct rb_root *root;
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if (work_busy(&ring->persistent_purge_work)) {
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pr_alert_ratelimited("Scheduled work from previous purge is still busy, cannot purge list\n");
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goto out;
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}
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if (ring->persistent_gnt_c < max_pgrants ||
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(ring->persistent_gnt_c == max_pgrants &&
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!ring->blkif->vbd.overflow_max_grants)) {
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num_clean = 0;
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} else {
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num_clean = (max_pgrants / 100) * LRU_PERCENT_CLEAN;
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num_clean = ring->persistent_gnt_c - max_pgrants + num_clean;
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num_clean = min(ring->persistent_gnt_c, num_clean);
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pr_debug("Going to purge at least %u persistent grants\n",
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num_clean);
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}
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|
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/*
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* At this point, we can assure that there will be no calls
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* to get_persistent_grant (because we are executing this code from
|
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* xen_blkif_schedule), there can only be calls to put_persistent_gnt,
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* which means that the number of currently used grants will go down,
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* but never up, so we will always be able to remove the requested
|
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* number of grants.
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*/
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total = 0;
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BUG_ON(!list_empty(&ring->persistent_purge_list));
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root = &ring->persistent_gnts;
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purge_list:
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foreach_grant_safe(persistent_gnt, n, root, node) {
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BUG_ON(persistent_gnt->handle ==
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BLKBACK_INVALID_HANDLE);
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|
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if (persistent_gnt->active)
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continue;
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if (!scan_used && !persistent_gnt_timeout(persistent_gnt))
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continue;
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if (scan_used && total >= num_clean)
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continue;
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|
|
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rb_erase(&persistent_gnt->node, root);
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list_add(&persistent_gnt->remove_node,
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&ring->persistent_purge_list);
|
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total++;
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}
|
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/*
|
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* Check whether we also need to start cleaning
|
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* grants that were used since last purge in order to cope
|
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* with the requested num
|
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*/
|
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if (!scan_used && total < num_clean) {
|
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pr_debug("Still missing %u purged frames\n", num_clean - total);
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scan_used = true;
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goto purge_list;
|
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}
|
|
|
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if (total) {
|
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ring->persistent_gnt_c -= total;
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ring->blkif->vbd.overflow_max_grants = 0;
|
|
|
|
/* We can defer this work */
|
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schedule_work(&ring->persistent_purge_work);
|
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pr_debug("Purged %u/%u\n", num_clean, total);
|
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}
|
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|
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out:
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return;
|
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}
|
|
|
|
/*
|
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* Retrieve from the 'pending_reqs' a free pending_req structure to be used.
|
|
*/
|
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static struct pending_req *alloc_req(struct xen_blkif_ring *ring)
|
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{
|
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struct pending_req *req = NULL;
|
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unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ring->pending_free_lock, flags);
|
|
if (!list_empty(&ring->pending_free)) {
|
|
req = list_entry(ring->pending_free.next, struct pending_req,
|
|
free_list);
|
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list_del(&req->free_list);
|
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}
|
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spin_unlock_irqrestore(&ring->pending_free_lock, flags);
|
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return req;
|
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}
|
|
|
|
/*
|
|
* Return the 'pending_req' structure back to the freepool. We also
|
|
* wake up the thread if it was waiting for a free page.
|
|
*/
|
|
static void free_req(struct xen_blkif_ring *ring, struct pending_req *req)
|
|
{
|
|
unsigned long flags;
|
|
int was_empty;
|
|
|
|
spin_lock_irqsave(&ring->pending_free_lock, flags);
|
|
was_empty = list_empty(&ring->pending_free);
|
|
list_add(&req->free_list, &ring->pending_free);
|
|
spin_unlock_irqrestore(&ring->pending_free_lock, flags);
|
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if (was_empty)
|
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wake_up(&ring->pending_free_wq);
|
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}
|
|
|
|
/*
|
|
* Routines for managing virtual block devices (vbds).
|
|
*/
|
|
static int xen_vbd_translate(struct phys_req *req, struct xen_blkif *blkif,
|
|
int operation)
|
|
{
|
|
struct xen_vbd *vbd = &blkif->vbd;
|
|
int rc = -EACCES;
|
|
|
|
if ((operation != REQ_OP_READ) && vbd->readonly)
|
|
goto out;
|
|
|
|
if (likely(req->nr_sects)) {
|
|
blkif_sector_t end = req->sector_number + req->nr_sects;
|
|
|
|
if (unlikely(end < req->sector_number))
|
|
goto out;
|
|
if (unlikely(end > vbd_sz(vbd)))
|
|
goto out;
|
|
}
|
|
|
|
req->dev = vbd->pdevice;
|
|
req->bdev = vbd->bdev;
|
|
rc = 0;
|
|
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
static void xen_vbd_resize(struct xen_blkif *blkif)
|
|
{
|
|
struct xen_vbd *vbd = &blkif->vbd;
|
|
struct xenbus_transaction xbt;
|
|
int err;
|
|
struct xenbus_device *dev = xen_blkbk_xenbus(blkif->be);
|
|
unsigned long long new_size = vbd_sz(vbd);
|
|
|
|
pr_info("VBD Resize: Domid: %d, Device: (%d, %d)\n",
|
|
blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice));
|
|
pr_info("VBD Resize: new size %llu\n", new_size);
|
|
vbd->size = new_size;
|
|
again:
|
|
err = xenbus_transaction_start(&xbt);
|
|
if (err) {
|
|
pr_warn("Error starting transaction\n");
|
|
return;
|
|
}
|
|
err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
|
|
(unsigned long long)vbd_sz(vbd));
|
|
if (err) {
|
|
pr_warn("Error writing new size\n");
|
|
goto abort;
|
|
}
|
|
/*
|
|
* Write the current state; we will use this to synchronize
|
|
* the front-end. If the current state is "connected" the
|
|
* front-end will get the new size information online.
|
|
*/
|
|
err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state);
|
|
if (err) {
|
|
pr_warn("Error writing the state\n");
|
|
goto abort;
|
|
}
|
|
|
|
err = xenbus_transaction_end(xbt, 0);
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
if (err)
|
|
pr_warn("Error ending transaction\n");
|
|
return;
|
|
abort:
|
|
xenbus_transaction_end(xbt, 1);
|
|
}
|
|
|
|
/*
|
|
* Notification from the guest OS.
|
|
*/
|
|
static void blkif_notify_work(struct xen_blkif_ring *ring)
|
|
{
|
|
ring->waiting_reqs = 1;
|
|
wake_up(&ring->wq);
|
|
}
|
|
|
|
irqreturn_t xen_blkif_be_int(int irq, void *dev_id)
|
|
{
|
|
blkif_notify_work(dev_id);
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
/*
|
|
* SCHEDULER FUNCTIONS
|
|
*/
|
|
|
|
static void print_stats(struct xen_blkif_ring *ring)
|
|
{
|
|
pr_info("(%s): oo %3llu | rd %4llu | wr %4llu | f %4llu"
|
|
" | ds %4llu | pg: %4u/%4d\n",
|
|
current->comm, ring->st_oo_req,
|
|
ring->st_rd_req, ring->st_wr_req,
|
|
ring->st_f_req, ring->st_ds_req,
|
|
ring->persistent_gnt_c, max_pgrants);
|
|
ring->st_print = jiffies + msecs_to_jiffies(10 * 1000);
|
|
ring->st_rd_req = 0;
|
|
ring->st_wr_req = 0;
|
|
ring->st_oo_req = 0;
|
|
ring->st_ds_req = 0;
|
|
}
|
|
|
|
int xen_blkif_schedule(void *arg)
|
|
{
|
|
struct xen_blkif_ring *ring = arg;
|
|
struct xen_blkif *blkif = ring->blkif;
|
|
struct xen_vbd *vbd = &blkif->vbd;
|
|
unsigned long timeout;
|
|
int ret;
|
|
bool do_eoi;
|
|
unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
|
|
|
|
set_freezable();
|
|
while (!kthread_should_stop()) {
|
|
if (try_to_freeze())
|
|
continue;
|
|
if (unlikely(vbd->size != vbd_sz(vbd)))
|
|
xen_vbd_resize(blkif);
|
|
|
|
timeout = msecs_to_jiffies(LRU_INTERVAL);
|
|
|
|
timeout = wait_event_interruptible_timeout(
|
|
ring->wq,
|
|
ring->waiting_reqs || kthread_should_stop(),
|
|
timeout);
|
|
if (timeout == 0)
|
|
goto purge_gnt_list;
|
|
timeout = wait_event_interruptible_timeout(
|
|
ring->pending_free_wq,
|
|
!list_empty(&ring->pending_free) ||
|
|
kthread_should_stop(),
|
|
timeout);
|
|
if (timeout == 0)
|
|
goto purge_gnt_list;
|
|
|
|
do_eoi = ring->waiting_reqs;
|
|
|
|
ring->waiting_reqs = 0;
|
|
smp_mb(); /* clear flag *before* checking for work */
|
|
|
|
ret = do_block_io_op(ring, &eoi_flags);
|
|
if (ret > 0)
|
|
ring->waiting_reqs = 1;
|
|
if (ret == -EACCES)
|
|
wait_event_interruptible(ring->shutdown_wq,
|
|
kthread_should_stop());
|
|
|
|
if (do_eoi && !ring->waiting_reqs) {
|
|
xen_irq_lateeoi(ring->irq, eoi_flags);
|
|
eoi_flags |= XEN_EOI_FLAG_SPURIOUS;
|
|
}
|
|
|
|
purge_gnt_list:
|
|
if (blkif->vbd.feature_gnt_persistent &&
|
|
time_after(jiffies, ring->next_lru)) {
|
|
purge_persistent_gnt(ring);
|
|
ring->next_lru = jiffies + msecs_to_jiffies(LRU_INTERVAL);
|
|
}
|
|
|
|
/* Shrink the free pages pool if it is too large. */
|
|
if (time_before(jiffies, blkif->buffer_squeeze_end))
|
|
gnttab_page_cache_shrink(&ring->free_pages, 0);
|
|
else
|
|
gnttab_page_cache_shrink(&ring->free_pages,
|
|
max_buffer_pages);
|
|
|
|
if (log_stats && time_after(jiffies, ring->st_print))
|
|
print_stats(ring);
|
|
}
|
|
|
|
/* Drain pending purge work */
|
|
flush_work(&ring->persistent_purge_work);
|
|
|
|
if (log_stats)
|
|
print_stats(ring);
|
|
|
|
ring->xenblkd = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Remove persistent grants and empty the pool of free pages
|
|
*/
|
|
void xen_blkbk_free_caches(struct xen_blkif_ring *ring)
|
|
{
|
|
/* Free all persistent grant pages */
|
|
if (!RB_EMPTY_ROOT(&ring->persistent_gnts))
|
|
free_persistent_gnts(ring, &ring->persistent_gnts,
|
|
ring->persistent_gnt_c);
|
|
|
|
BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts));
|
|
ring->persistent_gnt_c = 0;
|
|
|
|
/* Since we are shutting down remove all pages from the buffer */
|
|
gnttab_page_cache_shrink(&ring->free_pages, 0 /* All */);
|
|
}
|
|
|
|
static unsigned int xen_blkbk_unmap_prepare(
|
|
struct xen_blkif_ring *ring,
|
|
struct grant_page **pages,
|
|
unsigned int num,
|
|
struct gnttab_unmap_grant_ref *unmap_ops,
|
|
struct page **unmap_pages)
|
|
{
|
|
unsigned int i, invcount = 0;
|
|
|
|
for (i = 0; i < num; i++) {
|
|
if (pages[i]->persistent_gnt != NULL) {
|
|
put_persistent_gnt(ring, pages[i]->persistent_gnt);
|
|
continue;
|
|
}
|
|
if (pages[i]->handle == BLKBACK_INVALID_HANDLE)
|
|
continue;
|
|
unmap_pages[invcount] = pages[i]->page;
|
|
gnttab_set_unmap_op(&unmap_ops[invcount], vaddr(pages[i]->page),
|
|
GNTMAP_host_map, pages[i]->handle);
|
|
pages[i]->handle = BLKBACK_INVALID_HANDLE;
|
|
invcount++;
|
|
}
|
|
|
|
return invcount;
|
|
}
|
|
|
|
static void xen_blkbk_unmap_and_respond_callback(int result, struct gntab_unmap_queue_data *data)
|
|
{
|
|
struct pending_req *pending_req = (struct pending_req *)(data->data);
|
|
struct xen_blkif_ring *ring = pending_req->ring;
|
|
struct xen_blkif *blkif = ring->blkif;
|
|
|
|
/* BUG_ON used to reproduce existing behaviour,
|
|
but is this the best way to deal with this? */
|
|
BUG_ON(result);
|
|
|
|
gnttab_page_cache_put(&ring->free_pages, data->pages, data->count);
|
|
make_response(ring, pending_req->id,
|
|
pending_req->operation, pending_req->status);
|
|
free_req(ring, pending_req);
|
|
/*
|
|
* Make sure the request is freed before releasing blkif,
|
|
* or there could be a race between free_req and the
|
|
* cleanup done in xen_blkif_free during shutdown.
|
|
*
|
|
* NB: The fact that we might try to wake up pending_free_wq
|
|
* before drain_complete (in case there's a drain going on)
|
|
* it's not a problem with our current implementation
|
|
* because we can assure there's no thread waiting on
|
|
* pending_free_wq if there's a drain going on, but it has
|
|
* to be taken into account if the current model is changed.
|
|
*/
|
|
if (atomic_dec_and_test(&ring->inflight) && atomic_read(&blkif->drain)) {
|
|
complete(&blkif->drain_complete);
|
|
}
|
|
xen_blkif_put(blkif);
|
|
}
|
|
|
|
static void xen_blkbk_unmap_and_respond(struct pending_req *req)
|
|
{
|
|
struct gntab_unmap_queue_data* work = &req->gnttab_unmap_data;
|
|
struct xen_blkif_ring *ring = req->ring;
|
|
struct grant_page **pages = req->segments;
|
|
unsigned int invcount;
|
|
|
|
invcount = xen_blkbk_unmap_prepare(ring, pages, req->nr_segs,
|
|
req->unmap, req->unmap_pages);
|
|
|
|
work->data = req;
|
|
work->done = xen_blkbk_unmap_and_respond_callback;
|
|
work->unmap_ops = req->unmap;
|
|
work->kunmap_ops = NULL;
|
|
work->pages = req->unmap_pages;
|
|
work->count = invcount;
|
|
|
|
gnttab_unmap_refs_async(&req->gnttab_unmap_data);
|
|
}
|
|
|
|
|
|
/*
|
|
* Unmap the grant references.
|
|
*
|
|
* This could accumulate ops up to the batch size to reduce the number
|
|
* of hypercalls, but since this is only used in error paths there's
|
|
* no real need.
|
|
*/
|
|
static void xen_blkbk_unmap(struct xen_blkif_ring *ring,
|
|
struct grant_page *pages[],
|
|
int num)
|
|
{
|
|
struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
|
|
struct page *unmap_pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
|
|
unsigned int invcount = 0;
|
|
int ret;
|
|
|
|
while (num) {
|
|
unsigned int batch = min(num, BLKIF_MAX_SEGMENTS_PER_REQUEST);
|
|
|
|
invcount = xen_blkbk_unmap_prepare(ring, pages, batch,
|
|
unmap, unmap_pages);
|
|
if (invcount) {
|
|
ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
|
|
BUG_ON(ret);
|
|
gnttab_page_cache_put(&ring->free_pages, unmap_pages,
|
|
invcount);
|
|
}
|
|
pages += batch;
|
|
num -= batch;
|
|
}
|
|
}
|
|
|
|
static int xen_blkbk_map(struct xen_blkif_ring *ring,
|
|
struct grant_page *pages[],
|
|
int num, bool ro)
|
|
{
|
|
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
|
|
struct page *pages_to_gnt[BLKIF_MAX_SEGMENTS_PER_REQUEST];
|
|
struct persistent_gnt *persistent_gnt = NULL;
|
|
phys_addr_t addr = 0;
|
|
int i, seg_idx, new_map_idx;
|
|
int segs_to_map = 0;
|
|
int ret = 0;
|
|
int last_map = 0, map_until = 0;
|
|
int use_persistent_gnts;
|
|
struct xen_blkif *blkif = ring->blkif;
|
|
|
|
use_persistent_gnts = (blkif->vbd.feature_gnt_persistent);
|
|
|
|
/*
|
|
* Fill out preq.nr_sects with proper amount of sectors, and setup
|
|
* assign map[..] with the PFN of the page in our domain with the
|
|
* corresponding grant reference for each page.
|
|
*/
|
|
again:
|
|
for (i = map_until; i < num; i++) {
|
|
uint32_t flags;
|
|
|
|
if (use_persistent_gnts) {
|
|
persistent_gnt = get_persistent_gnt(
|
|
ring,
|
|
pages[i]->gref);
|
|
}
|
|
|
|
if (persistent_gnt) {
|
|
/*
|
|
* We are using persistent grants and
|
|
* the grant is already mapped
|
|
*/
|
|
pages[i]->page = persistent_gnt->page;
|
|
pages[i]->persistent_gnt = persistent_gnt;
|
|
} else {
|
|
if (gnttab_page_cache_get(&ring->free_pages,
|
|
&pages[i]->page)) {
|
|
gnttab_page_cache_put(&ring->free_pages,
|
|
pages_to_gnt,
|
|
segs_to_map);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
addr = vaddr(pages[i]->page);
|
|
pages_to_gnt[segs_to_map] = pages[i]->page;
|
|
pages[i]->persistent_gnt = NULL;
|
|
flags = GNTMAP_host_map;
|
|
if (!use_persistent_gnts && ro)
|
|
flags |= GNTMAP_readonly;
|
|
gnttab_set_map_op(&map[segs_to_map++], addr,
|
|
flags, pages[i]->gref,
|
|
blkif->domid);
|
|
}
|
|
map_until = i + 1;
|
|
if (segs_to_map == BLKIF_MAX_SEGMENTS_PER_REQUEST)
|
|
break;
|
|
}
|
|
|
|
if (segs_to_map)
|
|
ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
|
|
|
|
/*
|
|
* Now swizzle the MFN in our domain with the MFN from the other domain
|
|
* so that when we access vaddr(pending_req,i) it has the contents of
|
|
* the page from the other domain.
|
|
*/
|
|
for (seg_idx = last_map, new_map_idx = 0; seg_idx < map_until; seg_idx++) {
|
|
if (!pages[seg_idx]->persistent_gnt) {
|
|
/* This is a newly mapped grant */
|
|
BUG_ON(new_map_idx >= segs_to_map);
|
|
if (unlikely(map[new_map_idx].status != 0)) {
|
|
pr_debug("invalid buffer -- could not remap it\n");
|
|
gnttab_page_cache_put(&ring->free_pages,
|
|
&pages[seg_idx]->page, 1);
|
|
pages[seg_idx]->handle = BLKBACK_INVALID_HANDLE;
|
|
ret |= !ret;
|
|
goto next;
|
|
}
|
|
pages[seg_idx]->handle = map[new_map_idx].handle;
|
|
} else {
|
|
continue;
|
|
}
|
|
if (use_persistent_gnts &&
|
|
ring->persistent_gnt_c < max_pgrants) {
|
|
/*
|
|
* We are using persistent grants, the grant is
|
|
* not mapped but we might have room for it.
|
|
*/
|
|
persistent_gnt = kmalloc(sizeof(struct persistent_gnt),
|
|
GFP_KERNEL);
|
|
if (!persistent_gnt) {
|
|
/*
|
|
* If we don't have enough memory to
|
|
* allocate the persistent_gnt struct
|
|
* map this grant non-persistenly
|
|
*/
|
|
goto next;
|
|
}
|
|
persistent_gnt->gnt = map[new_map_idx].ref;
|
|
persistent_gnt->handle = map[new_map_idx].handle;
|
|
persistent_gnt->page = pages[seg_idx]->page;
|
|
if (add_persistent_gnt(ring,
|
|
persistent_gnt)) {
|
|
kfree(persistent_gnt);
|
|
persistent_gnt = NULL;
|
|
goto next;
|
|
}
|
|
pages[seg_idx]->persistent_gnt = persistent_gnt;
|
|
pr_debug("grant %u added to the tree of persistent grants, using %u/%u\n",
|
|
persistent_gnt->gnt, ring->persistent_gnt_c,
|
|
max_pgrants);
|
|
goto next;
|
|
}
|
|
if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) {
|
|
blkif->vbd.overflow_max_grants = 1;
|
|
pr_debug("domain %u, device %#x is using maximum number of persistent grants\n",
|
|
blkif->domid, blkif->vbd.handle);
|
|
}
|
|
/*
|
|
* We could not map this grant persistently, so use it as
|
|
* a non-persistent grant.
|
|
*/
|
|
next:
|
|
new_map_idx++;
|
|
}
|
|
segs_to_map = 0;
|
|
last_map = map_until;
|
|
if (!ret && map_until != num)
|
|
goto again;
|
|
|
|
out:
|
|
for (i = last_map; i < num; i++) {
|
|
/* Don't zap current batch's valid persistent grants. */
|
|
if(i >= map_until)
|
|
pages[i]->persistent_gnt = NULL;
|
|
pages[i]->handle = BLKBACK_INVALID_HANDLE;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int xen_blkbk_map_seg(struct pending_req *pending_req)
|
|
{
|
|
int rc;
|
|
|
|
rc = xen_blkbk_map(pending_req->ring, pending_req->segments,
|
|
pending_req->nr_segs,
|
|
(pending_req->operation != BLKIF_OP_READ));
|
|
|
|
return rc;
|
|
}
|
|
|
|
static int xen_blkbk_parse_indirect(struct blkif_request *req,
|
|
struct pending_req *pending_req,
|
|
struct seg_buf seg[],
|
|
struct phys_req *preq)
|
|
{
|
|
struct grant_page **pages = pending_req->indirect_pages;
|
|
struct xen_blkif_ring *ring = pending_req->ring;
|
|
int indirect_grefs, rc, n, nseg, i;
|
|
struct blkif_request_segment *segments = NULL;
|
|
|
|
nseg = pending_req->nr_segs;
|
|
indirect_grefs = INDIRECT_PAGES(nseg);
|
|
BUG_ON(indirect_grefs > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
|
|
|
|
for (i = 0; i < indirect_grefs; i++)
|
|
pages[i]->gref = req->u.indirect.indirect_grefs[i];
|
|
|
|
rc = xen_blkbk_map(ring, pages, indirect_grefs, true);
|
|
if (rc)
|
|
goto unmap;
|
|
|
|
for (n = 0; n < nseg; n++) {
|
|
uint8_t first_sect, last_sect;
|
|
|
|
if ((n % SEGS_PER_INDIRECT_FRAME) == 0) {
|
|
/* Map indirect segments */
|
|
if (segments)
|
|
kunmap_atomic(segments);
|
|
segments = kmap_atomic(pages[n/SEGS_PER_INDIRECT_FRAME]->page);
|
|
}
|
|
i = n % SEGS_PER_INDIRECT_FRAME;
|
|
|
|
pending_req->segments[n]->gref = segments[i].gref;
|
|
|
|
first_sect = READ_ONCE(segments[i].first_sect);
|
|
last_sect = READ_ONCE(segments[i].last_sect);
|
|
if (last_sect >= (XEN_PAGE_SIZE >> 9) || last_sect < first_sect) {
|
|
rc = -EINVAL;
|
|
goto unmap;
|
|
}
|
|
|
|
seg[n].nsec = last_sect - first_sect + 1;
|
|
seg[n].offset = first_sect << 9;
|
|
preq->nr_sects += seg[n].nsec;
|
|
}
|
|
|
|
unmap:
|
|
if (segments)
|
|
kunmap_atomic(segments);
|
|
xen_blkbk_unmap(ring, pages, indirect_grefs);
|
|
return rc;
|
|
}
|
|
|
|
static int dispatch_discard_io(struct xen_blkif_ring *ring,
|
|
struct blkif_request *req)
|
|
{
|
|
int err = 0;
|
|
int status = BLKIF_RSP_OKAY;
|
|
struct xen_blkif *blkif = ring->blkif;
|
|
struct block_device *bdev = blkif->vbd.bdev;
|
|
unsigned long secure;
|
|
struct phys_req preq;
|
|
|
|
xen_blkif_get(blkif);
|
|
|
|
preq.sector_number = req->u.discard.sector_number;
|
|
preq.nr_sects = req->u.discard.nr_sectors;
|
|
|
|
err = xen_vbd_translate(&preq, blkif, REQ_OP_WRITE);
|
|
if (err) {
|
|
pr_warn("access denied: DISCARD [%llu->%llu] on dev=%04x\n",
|
|
preq.sector_number,
|
|
preq.sector_number + preq.nr_sects, blkif->vbd.pdevice);
|
|
goto fail_response;
|
|
}
|
|
ring->st_ds_req++;
|
|
|
|
secure = (blkif->vbd.discard_secure &&
|
|
(req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
|
|
BLKDEV_DISCARD_SECURE : 0;
|
|
|
|
err = blkdev_issue_discard(bdev, req->u.discard.sector_number,
|
|
req->u.discard.nr_sectors,
|
|
GFP_KERNEL, secure);
|
|
fail_response:
|
|
if (err == -EOPNOTSUPP) {
|
|
pr_debug("discard op failed, not supported\n");
|
|
status = BLKIF_RSP_EOPNOTSUPP;
|
|
} else if (err)
|
|
status = BLKIF_RSP_ERROR;
|
|
|
|
make_response(ring, req->u.discard.id, req->operation, status);
|
|
xen_blkif_put(blkif);
|
|
return err;
|
|
}
|
|
|
|
static int dispatch_other_io(struct xen_blkif_ring *ring,
|
|
struct blkif_request *req,
|
|
struct pending_req *pending_req)
|
|
{
|
|
free_req(ring, pending_req);
|
|
make_response(ring, req->u.other.id, req->operation,
|
|
BLKIF_RSP_EOPNOTSUPP);
|
|
return -EIO;
|
|
}
|
|
|
|
static void xen_blk_drain_io(struct xen_blkif_ring *ring)
|
|
{
|
|
struct xen_blkif *blkif = ring->blkif;
|
|
|
|
atomic_set(&blkif->drain, 1);
|
|
do {
|
|
if (atomic_read(&ring->inflight) == 0)
|
|
break;
|
|
wait_for_completion_interruptible_timeout(
|
|
&blkif->drain_complete, HZ);
|
|
|
|
if (!atomic_read(&blkif->drain))
|
|
break;
|
|
} while (!kthread_should_stop());
|
|
atomic_set(&blkif->drain, 0);
|
|
}
|
|
|
|
static void __end_block_io_op(struct pending_req *pending_req,
|
|
blk_status_t error)
|
|
{
|
|
/* An error fails the entire request. */
|
|
if (pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE &&
|
|
error == BLK_STS_NOTSUPP) {
|
|
pr_debug("flush diskcache op failed, not supported\n");
|
|
xen_blkbk_flush_diskcache(XBT_NIL, pending_req->ring->blkif->be, 0);
|
|
pending_req->status = BLKIF_RSP_EOPNOTSUPP;
|
|
} else if (pending_req->operation == BLKIF_OP_WRITE_BARRIER &&
|
|
error == BLK_STS_NOTSUPP) {
|
|
pr_debug("write barrier op failed, not supported\n");
|
|
xen_blkbk_barrier(XBT_NIL, pending_req->ring->blkif->be, 0);
|
|
pending_req->status = BLKIF_RSP_EOPNOTSUPP;
|
|
} else if (error) {
|
|
pr_debug("Buffer not up-to-date at end of operation,"
|
|
" error=%d\n", error);
|
|
pending_req->status = BLKIF_RSP_ERROR;
|
|
}
|
|
|
|
/*
|
|
* If all of the bio's have completed it is time to unmap
|
|
* the grant references associated with 'request' and provide
|
|
* the proper response on the ring.
|
|
*/
|
|
if (atomic_dec_and_test(&pending_req->pendcnt))
|
|
xen_blkbk_unmap_and_respond(pending_req);
|
|
}
|
|
|
|
/*
|
|
* bio callback.
|
|
*/
|
|
static void end_block_io_op(struct bio *bio)
|
|
{
|
|
__end_block_io_op(bio->bi_private, bio->bi_status);
|
|
bio_put(bio);
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* Function to copy the from the ring buffer the 'struct blkif_request'
|
|
* (which has the sectors we want, number of them, grant references, etc),
|
|
* and transmute it to the block API to hand it over to the proper block disk.
|
|
*/
|
|
static int
|
|
__do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags)
|
|
{
|
|
union blkif_back_rings *blk_rings = &ring->blk_rings;
|
|
struct blkif_request req;
|
|
struct pending_req *pending_req;
|
|
RING_IDX rc, rp;
|
|
int more_to_do = 0;
|
|
|
|
rc = blk_rings->common.req_cons;
|
|
rp = blk_rings->common.sring->req_prod;
|
|
rmb(); /* Ensure we see queued requests up to 'rp'. */
|
|
|
|
if (RING_REQUEST_PROD_OVERFLOW(&blk_rings->common, rp)) {
|
|
rc = blk_rings->common.rsp_prod_pvt;
|
|
pr_warn("Frontend provided bogus ring requests (%d - %d = %d). Halting ring processing on dev=%04x\n",
|
|
rp, rc, rp - rc, ring->blkif->vbd.pdevice);
|
|
return -EACCES;
|
|
}
|
|
while (rc != rp) {
|
|
|
|
if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
|
|
break;
|
|
|
|
/* We've seen a request, so clear spurious eoi flag. */
|
|
*eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
|
|
|
|
if (kthread_should_stop()) {
|
|
more_to_do = 1;
|
|
break;
|
|
}
|
|
|
|
pending_req = alloc_req(ring);
|
|
if (NULL == pending_req) {
|
|
ring->st_oo_req++;
|
|
more_to_do = 1;
|
|
break;
|
|
}
|
|
|
|
switch (ring->blkif->blk_protocol) {
|
|
case BLKIF_PROTOCOL_NATIVE:
|
|
memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req));
|
|
break;
|
|
case BLKIF_PROTOCOL_X86_32:
|
|
blkif_get_x86_32_req(&req, RING_GET_REQUEST(&blk_rings->x86_32, rc));
|
|
break;
|
|
case BLKIF_PROTOCOL_X86_64:
|
|
blkif_get_x86_64_req(&req, RING_GET_REQUEST(&blk_rings->x86_64, rc));
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
blk_rings->common.req_cons = ++rc; /* before make_response() */
|
|
|
|
/* Apply all sanity checks to /private copy/ of request. */
|
|
barrier();
|
|
|
|
switch (req.operation) {
|
|
case BLKIF_OP_READ:
|
|
case BLKIF_OP_WRITE:
|
|
case BLKIF_OP_WRITE_BARRIER:
|
|
case BLKIF_OP_FLUSH_DISKCACHE:
|
|
case BLKIF_OP_INDIRECT:
|
|
if (dispatch_rw_block_io(ring, &req, pending_req))
|
|
goto done;
|
|
break;
|
|
case BLKIF_OP_DISCARD:
|
|
free_req(ring, pending_req);
|
|
if (dispatch_discard_io(ring, &req))
|
|
goto done;
|
|
break;
|
|
default:
|
|
if (dispatch_other_io(ring, &req, pending_req))
|
|
goto done;
|
|
break;
|
|
}
|
|
|
|
/* Yield point for this unbounded loop. */
|
|
cond_resched();
|
|
}
|
|
done:
|
|
return more_to_do;
|
|
}
|
|
|
|
static int
|
|
do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags)
|
|
{
|
|
union blkif_back_rings *blk_rings = &ring->blk_rings;
|
|
int more_to_do;
|
|
|
|
do {
|
|
more_to_do = __do_block_io_op(ring, eoi_flags);
|
|
if (more_to_do)
|
|
break;
|
|
|
|
RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do);
|
|
} while (more_to_do);
|
|
|
|
return more_to_do;
|
|
}
|
|
/*
|
|
* Transmutation of the 'struct blkif_request' to a proper 'struct bio'
|
|
* and call the 'submit_bio' to pass it to the underlying storage.
|
|
*/
|
|
static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
|
|
struct blkif_request *req,
|
|
struct pending_req *pending_req)
|
|
{
|
|
struct phys_req preq;
|
|
struct seg_buf *seg = pending_req->seg;
|
|
unsigned int nseg;
|
|
struct bio *bio = NULL;
|
|
struct bio **biolist = pending_req->biolist;
|
|
int i, nbio = 0;
|
|
int operation;
|
|
int operation_flags = 0;
|
|
struct blk_plug plug;
|
|
bool drain = false;
|
|
struct grant_page **pages = pending_req->segments;
|
|
unsigned short req_operation;
|
|
|
|
req_operation = req->operation == BLKIF_OP_INDIRECT ?
|
|
req->u.indirect.indirect_op : req->operation;
|
|
|
|
if ((req->operation == BLKIF_OP_INDIRECT) &&
|
|
(req_operation != BLKIF_OP_READ) &&
|
|
(req_operation != BLKIF_OP_WRITE)) {
|
|
pr_debug("Invalid indirect operation (%u)\n", req_operation);
|
|
goto fail_response;
|
|
}
|
|
|
|
switch (req_operation) {
|
|
case BLKIF_OP_READ:
|
|
ring->st_rd_req++;
|
|
operation = REQ_OP_READ;
|
|
break;
|
|
case BLKIF_OP_WRITE:
|
|
ring->st_wr_req++;
|
|
operation = REQ_OP_WRITE;
|
|
operation_flags = REQ_SYNC | REQ_IDLE;
|
|
break;
|
|
case BLKIF_OP_WRITE_BARRIER:
|
|
drain = true;
|
|
fallthrough;
|
|
case BLKIF_OP_FLUSH_DISKCACHE:
|
|
ring->st_f_req++;
|
|
operation = REQ_OP_WRITE;
|
|
operation_flags = REQ_PREFLUSH;
|
|
break;
|
|
default:
|
|
operation = 0; /* make gcc happy */
|
|
goto fail_response;
|
|
break;
|
|
}
|
|
|
|
/* Check that the number of segments is sane. */
|
|
nseg = req->operation == BLKIF_OP_INDIRECT ?
|
|
req->u.indirect.nr_segments : req->u.rw.nr_segments;
|
|
|
|
if (unlikely(nseg == 0 && operation_flags != REQ_PREFLUSH) ||
|
|
unlikely((req->operation != BLKIF_OP_INDIRECT) &&
|
|
(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) ||
|
|
unlikely((req->operation == BLKIF_OP_INDIRECT) &&
|
|
(nseg > MAX_INDIRECT_SEGMENTS))) {
|
|
pr_debug("Bad number of segments in request (%d)\n", nseg);
|
|
/* Haven't submitted any bio's yet. */
|
|
goto fail_response;
|
|
}
|
|
|
|
preq.nr_sects = 0;
|
|
|
|
pending_req->ring = ring;
|
|
pending_req->id = req->u.rw.id;
|
|
pending_req->operation = req_operation;
|
|
pending_req->status = BLKIF_RSP_OKAY;
|
|
pending_req->nr_segs = nseg;
|
|
|
|
if (req->operation != BLKIF_OP_INDIRECT) {
|
|
preq.dev = req->u.rw.handle;
|
|
preq.sector_number = req->u.rw.sector_number;
|
|
for (i = 0; i < nseg; i++) {
|
|
pages[i]->gref = req->u.rw.seg[i].gref;
|
|
seg[i].nsec = req->u.rw.seg[i].last_sect -
|
|
req->u.rw.seg[i].first_sect + 1;
|
|
seg[i].offset = (req->u.rw.seg[i].first_sect << 9);
|
|
if ((req->u.rw.seg[i].last_sect >= (XEN_PAGE_SIZE >> 9)) ||
|
|
(req->u.rw.seg[i].last_sect <
|
|
req->u.rw.seg[i].first_sect))
|
|
goto fail_response;
|
|
preq.nr_sects += seg[i].nsec;
|
|
}
|
|
} else {
|
|
preq.dev = req->u.indirect.handle;
|
|
preq.sector_number = req->u.indirect.sector_number;
|
|
if (xen_blkbk_parse_indirect(req, pending_req, seg, &preq))
|
|
goto fail_response;
|
|
}
|
|
|
|
if (xen_vbd_translate(&preq, ring->blkif, operation) != 0) {
|
|
pr_debug("access denied: %s of [%llu,%llu] on dev=%04x\n",
|
|
operation == REQ_OP_READ ? "read" : "write",
|
|
preq.sector_number,
|
|
preq.sector_number + preq.nr_sects,
|
|
ring->blkif->vbd.pdevice);
|
|
goto fail_response;
|
|
}
|
|
|
|
/*
|
|
* This check _MUST_ be done after xen_vbd_translate as the preq.bdev
|
|
* is set there.
|
|
*/
|
|
for (i = 0; i < nseg; i++) {
|
|
if (((int)preq.sector_number|(int)seg[i].nsec) &
|
|
((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
|
|
pr_debug("Misaligned I/O request from domain %d\n",
|
|
ring->blkif->domid);
|
|
goto fail_response;
|
|
}
|
|
}
|
|
|
|
/* Wait on all outstanding I/O's and once that has been completed
|
|
* issue the flush.
|
|
*/
|
|
if (drain)
|
|
xen_blk_drain_io(pending_req->ring);
|
|
|
|
/*
|
|
* If we have failed at this point, we need to undo the M2P override,
|
|
* set gnttab_set_unmap_op on all of the grant references and perform
|
|
* the hypercall to unmap the grants - that is all done in
|
|
* xen_blkbk_unmap.
|
|
*/
|
|
if (xen_blkbk_map_seg(pending_req))
|
|
goto fail_flush;
|
|
|
|
/*
|
|
* This corresponding xen_blkif_put is done in __end_block_io_op, or
|
|
* below (in "!bio") if we are handling a BLKIF_OP_DISCARD.
|
|
*/
|
|
xen_blkif_get(ring->blkif);
|
|
atomic_inc(&ring->inflight);
|
|
|
|
for (i = 0; i < nseg; i++) {
|
|
while ((bio == NULL) ||
|
|
(bio_add_page(bio,
|
|
pages[i]->page,
|
|
seg[i].nsec << 9,
|
|
seg[i].offset) == 0)) {
|
|
bio = bio_alloc(preq.bdev, bio_max_segs(nseg - i),
|
|
operation | operation_flags,
|
|
GFP_KERNEL);
|
|
biolist[nbio++] = bio;
|
|
bio->bi_private = pending_req;
|
|
bio->bi_end_io = end_block_io_op;
|
|
bio->bi_iter.bi_sector = preq.sector_number;
|
|
}
|
|
|
|
preq.sector_number += seg[i].nsec;
|
|
}
|
|
|
|
/* This will be hit if the operation was a flush or discard. */
|
|
if (!bio) {
|
|
BUG_ON(operation_flags != REQ_PREFLUSH);
|
|
|
|
bio = bio_alloc(preq.bdev, 0, operation | operation_flags,
|
|
GFP_KERNEL);
|
|
biolist[nbio++] = bio;
|
|
bio->bi_private = pending_req;
|
|
bio->bi_end_io = end_block_io_op;
|
|
}
|
|
|
|
atomic_set(&pending_req->pendcnt, nbio);
|
|
blk_start_plug(&plug);
|
|
|
|
for (i = 0; i < nbio; i++)
|
|
submit_bio(biolist[i]);
|
|
|
|
/* Let the I/Os go.. */
|
|
blk_finish_plug(&plug);
|
|
|
|
if (operation == REQ_OP_READ)
|
|
ring->st_rd_sect += preq.nr_sects;
|
|
else if (operation == REQ_OP_WRITE)
|
|
ring->st_wr_sect += preq.nr_sects;
|
|
|
|
return 0;
|
|
|
|
fail_flush:
|
|
xen_blkbk_unmap(ring, pending_req->segments,
|
|
pending_req->nr_segs);
|
|
fail_response:
|
|
/* Haven't submitted any bio's yet. */
|
|
make_response(ring, req->u.rw.id, req_operation, BLKIF_RSP_ERROR);
|
|
free_req(ring, pending_req);
|
|
msleep(1); /* back off a bit */
|
|
return -EIO;
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* Put a response on the ring on how the operation fared.
|
|
*/
|
|
static void make_response(struct xen_blkif_ring *ring, u64 id,
|
|
unsigned short op, int st)
|
|
{
|
|
struct blkif_response *resp;
|
|
unsigned long flags;
|
|
union blkif_back_rings *blk_rings;
|
|
int notify;
|
|
|
|
spin_lock_irqsave(&ring->blk_ring_lock, flags);
|
|
blk_rings = &ring->blk_rings;
|
|
/* Place on the response ring for the relevant domain. */
|
|
switch (ring->blkif->blk_protocol) {
|
|
case BLKIF_PROTOCOL_NATIVE:
|
|
resp = RING_GET_RESPONSE(&blk_rings->native,
|
|
blk_rings->native.rsp_prod_pvt);
|
|
break;
|
|
case BLKIF_PROTOCOL_X86_32:
|
|
resp = RING_GET_RESPONSE(&blk_rings->x86_32,
|
|
blk_rings->x86_32.rsp_prod_pvt);
|
|
break;
|
|
case BLKIF_PROTOCOL_X86_64:
|
|
resp = RING_GET_RESPONSE(&blk_rings->x86_64,
|
|
blk_rings->x86_64.rsp_prod_pvt);
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
|
|
resp->id = id;
|
|
resp->operation = op;
|
|
resp->status = st;
|
|
|
|
blk_rings->common.rsp_prod_pvt++;
|
|
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify);
|
|
spin_unlock_irqrestore(&ring->blk_ring_lock, flags);
|
|
if (notify)
|
|
notify_remote_via_irq(ring->irq);
|
|
}
|
|
|
|
static int __init xen_blkif_init(void)
|
|
{
|
|
int rc = 0;
|
|
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
|
|
pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
|
|
xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
|
|
xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
|
|
}
|
|
|
|
if (xenblk_max_queues == 0)
|
|
xenblk_max_queues = num_online_cpus();
|
|
|
|
rc = xen_blkif_interface_init();
|
|
if (rc)
|
|
goto failed_init;
|
|
|
|
rc = xen_blkif_xenbus_init();
|
|
if (rc)
|
|
goto failed_init;
|
|
|
|
failed_init:
|
|
return rc;
|
|
}
|
|
|
|
module_init(xen_blkif_init);
|
|
|
|
static void __exit xen_blkif_fini(void)
|
|
{
|
|
xen_blkif_xenbus_fini();
|
|
xen_blkif_interface_fini();
|
|
}
|
|
|
|
module_exit(xen_blkif_fini);
|
|
|
|
MODULE_LICENSE("Dual BSD/GPL");
|
|
MODULE_ALIAS("xen-backend:vbd");
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