440 lines
12 KiB
C
440 lines
12 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com>
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* Copyright(c) 2009 Intel Corporation
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/dma-mapping.h>
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#include <linux/raid/pq.h>
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#include <linux/async_tx.h>
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#include <linux/gfp.h>
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/**
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* pq_scribble_page - space to hold throwaway P or Q buffer for
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* synchronous gen_syndrome
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*/
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static struct page *pq_scribble_page;
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/* the struct page *blocks[] parameter passed to async_gen_syndrome()
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* and async_syndrome_val() contains the 'P' destination address at
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* blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
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*
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* note: these are macros as they are used as lvalues
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*/
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#define P(b, d) (b[d-2])
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#define Q(b, d) (b[d-1])
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#define MAX_DISKS 255
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/**
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* do_async_gen_syndrome - asynchronously calculate P and/or Q
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*/
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static __async_inline struct dma_async_tx_descriptor *
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do_async_gen_syndrome(struct dma_chan *chan,
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const unsigned char *scfs, int disks,
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struct dmaengine_unmap_data *unmap,
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enum dma_ctrl_flags dma_flags,
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struct async_submit_ctl *submit)
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{
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struct dma_async_tx_descriptor *tx = NULL;
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struct dma_device *dma = chan->device;
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enum async_tx_flags flags_orig = submit->flags;
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dma_async_tx_callback cb_fn_orig = submit->cb_fn;
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dma_async_tx_callback cb_param_orig = submit->cb_param;
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int src_cnt = disks - 2;
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unsigned short pq_src_cnt;
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dma_addr_t dma_dest[2];
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int src_off = 0;
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while (src_cnt > 0) {
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submit->flags = flags_orig;
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pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
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/* if we are submitting additional pqs, leave the chain open,
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* clear the callback parameters, and leave the destination
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* buffers mapped
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*/
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if (src_cnt > pq_src_cnt) {
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submit->flags &= ~ASYNC_TX_ACK;
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submit->flags |= ASYNC_TX_FENCE;
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submit->cb_fn = NULL;
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submit->cb_param = NULL;
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} else {
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submit->cb_fn = cb_fn_orig;
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submit->cb_param = cb_param_orig;
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if (cb_fn_orig)
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dma_flags |= DMA_PREP_INTERRUPT;
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}
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if (submit->flags & ASYNC_TX_FENCE)
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dma_flags |= DMA_PREP_FENCE;
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/* Drivers force forward progress in case they can not provide
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* a descriptor
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*/
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for (;;) {
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dma_dest[0] = unmap->addr[disks - 2];
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dma_dest[1] = unmap->addr[disks - 1];
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tx = dma->device_prep_dma_pq(chan, dma_dest,
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&unmap->addr[src_off],
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pq_src_cnt,
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&scfs[src_off], unmap->len,
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dma_flags);
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if (likely(tx))
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break;
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async_tx_quiesce(&submit->depend_tx);
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dma_async_issue_pending(chan);
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}
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dma_set_unmap(tx, unmap);
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async_tx_submit(chan, tx, submit);
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submit->depend_tx = tx;
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/* drop completed sources */
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src_cnt -= pq_src_cnt;
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src_off += pq_src_cnt;
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dma_flags |= DMA_PREP_CONTINUE;
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}
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return tx;
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}
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/**
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* do_sync_gen_syndrome - synchronously calculate a raid6 syndrome
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*/
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static void
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do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
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size_t len, struct async_submit_ctl *submit)
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{
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void **srcs;
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int i;
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int start = -1, stop = disks - 3;
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if (submit->scribble)
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srcs = submit->scribble;
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else
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srcs = (void **) blocks;
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for (i = 0; i < disks; i++) {
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if (blocks[i] == NULL) {
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BUG_ON(i > disks - 3); /* P or Q can't be zero */
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srcs[i] = (void*)raid6_empty_zero_page;
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} else {
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srcs[i] = page_address(blocks[i]) + offset;
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if (i < disks - 2) {
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stop = i;
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if (start == -1)
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start = i;
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}
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}
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}
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if (submit->flags & ASYNC_TX_PQ_XOR_DST) {
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BUG_ON(!raid6_call.xor_syndrome);
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if (start >= 0)
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raid6_call.xor_syndrome(disks, start, stop, len, srcs);
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} else
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raid6_call.gen_syndrome(disks, len, srcs);
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async_tx_sync_epilog(submit);
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}
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/**
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* async_gen_syndrome - asynchronously calculate a raid6 syndrome
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* @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
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* @offset: common offset into each block (src and dest) to start transaction
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* @disks: number of blocks (including missing P or Q, see below)
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* @len: length of operation in bytes
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* @submit: submission/completion modifiers
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*
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* General note: This routine assumes a field of GF(2^8) with a
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* primitive polynomial of 0x11d and a generator of {02}.
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*
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* 'disks' note: callers can optionally omit either P or Q (but not
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* both) from the calculation by setting blocks[disks-2] or
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* blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <=
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* PAGE_SIZE as a temporary buffer of this size is used in the
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* synchronous path. 'disks' always accounts for both destination
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* buffers. If any source buffers (blocks[i] where i < disks - 2) are
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* set to NULL those buffers will be replaced with the raid6_zero_page
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* in the synchronous path and omitted in the hardware-asynchronous
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* path.
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*/
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struct dma_async_tx_descriptor *
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async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
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size_t len, struct async_submit_ctl *submit)
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{
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int src_cnt = disks - 2;
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ,
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&P(blocks, disks), 2,
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blocks, src_cnt, len);
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struct dma_device *device = chan ? chan->device : NULL;
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struct dmaengine_unmap_data *unmap = NULL;
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BUG_ON(disks > MAX_DISKS || !(P(blocks, disks) || Q(blocks, disks)));
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if (device)
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unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
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/* XORing P/Q is only implemented in software */
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if (unmap && !(submit->flags & ASYNC_TX_PQ_XOR_DST) &&
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(src_cnt <= dma_maxpq(device, 0) ||
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dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
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is_dma_pq_aligned(device, offset, 0, len)) {
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struct dma_async_tx_descriptor *tx;
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enum dma_ctrl_flags dma_flags = 0;
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unsigned char coefs[MAX_DISKS];
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int i, j;
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/* run the p+q asynchronously */
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pr_debug("%s: (async) disks: %d len: %zu\n",
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__func__, disks, len);
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/* convert source addresses being careful to collapse 'empty'
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* sources and update the coefficients accordingly
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*/
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unmap->len = len;
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for (i = 0, j = 0; i < src_cnt; i++) {
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if (blocks[i] == NULL)
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continue;
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unmap->addr[j] = dma_map_page(device->dev, blocks[i], offset,
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len, DMA_TO_DEVICE);
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coefs[j] = raid6_gfexp[i];
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unmap->to_cnt++;
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j++;
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}
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/*
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* DMAs use destinations as sources,
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* so use BIDIRECTIONAL mapping
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*/
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unmap->bidi_cnt++;
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if (P(blocks, disks))
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unmap->addr[j++] = dma_map_page(device->dev, P(blocks, disks),
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offset, len, DMA_BIDIRECTIONAL);
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else {
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unmap->addr[j++] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_P;
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}
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unmap->bidi_cnt++;
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if (Q(blocks, disks))
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unmap->addr[j++] = dma_map_page(device->dev, Q(blocks, disks),
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offset, len, DMA_BIDIRECTIONAL);
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else {
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unmap->addr[j++] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_Q;
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}
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tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, submit);
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dmaengine_unmap_put(unmap);
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return tx;
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}
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dmaengine_unmap_put(unmap);
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/* run the pq synchronously */
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pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len);
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/* wait for any prerequisite operations */
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async_tx_quiesce(&submit->depend_tx);
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if (!P(blocks, disks)) {
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P(blocks, disks) = pq_scribble_page;
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BUG_ON(len + offset > PAGE_SIZE);
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}
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if (!Q(blocks, disks)) {
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Q(blocks, disks) = pq_scribble_page;
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BUG_ON(len + offset > PAGE_SIZE);
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}
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do_sync_gen_syndrome(blocks, offset, disks, len, submit);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(async_gen_syndrome);
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static inline struct dma_chan *
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pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len)
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{
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#ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
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return NULL;
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#endif
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return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks,
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disks, len);
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}
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/**
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* async_syndrome_val - asynchronously validate a raid6 syndrome
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* @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1
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* @offset: common offset into each block (src and dest) to start transaction
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* @disks: number of blocks (including missing P or Q, see below)
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* @len: length of operation in bytes
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* @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set
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* @spare: temporary result buffer for the synchronous case
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* @submit: submission / completion modifiers
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*
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* The same notes from async_gen_syndrome apply to the 'blocks',
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* and 'disks' parameters of this routine. The synchronous path
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* requires a temporary result buffer and submit->scribble to be
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* specified.
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*/
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struct dma_async_tx_descriptor *
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async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
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size_t len, enum sum_check_flags *pqres, struct page *spare,
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struct async_submit_ctl *submit)
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{
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struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
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struct dma_device *device = chan ? chan->device : NULL;
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struct dma_async_tx_descriptor *tx;
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unsigned char coefs[MAX_DISKS];
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enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
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struct dmaengine_unmap_data *unmap = NULL;
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BUG_ON(disks < 4 || disks > MAX_DISKS);
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if (device)
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unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
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if (unmap && disks <= dma_maxpq(device, 0) &&
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is_dma_pq_aligned(device, offset, 0, len)) {
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struct device *dev = device->dev;
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dma_addr_t pq[2];
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int i, j = 0, src_cnt = 0;
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pr_debug("%s: (async) disks: %d len: %zu\n",
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__func__, disks, len);
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unmap->len = len;
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for (i = 0; i < disks-2; i++)
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if (likely(blocks[i])) {
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unmap->addr[j] = dma_map_page(dev, blocks[i],
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offset, len,
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DMA_TO_DEVICE);
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coefs[j] = raid6_gfexp[i];
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unmap->to_cnt++;
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src_cnt++;
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j++;
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}
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if (!P(blocks, disks)) {
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pq[0] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_P;
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} else {
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pq[0] = dma_map_page(dev, P(blocks, disks),
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offset, len,
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DMA_TO_DEVICE);
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unmap->addr[j++] = pq[0];
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unmap->to_cnt++;
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}
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if (!Q(blocks, disks)) {
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pq[1] = 0;
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dma_flags |= DMA_PREP_PQ_DISABLE_Q;
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} else {
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pq[1] = dma_map_page(dev, Q(blocks, disks),
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offset, len,
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DMA_TO_DEVICE);
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unmap->addr[j++] = pq[1];
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unmap->to_cnt++;
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}
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if (submit->flags & ASYNC_TX_FENCE)
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dma_flags |= DMA_PREP_FENCE;
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for (;;) {
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tx = device->device_prep_dma_pq_val(chan, pq,
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unmap->addr,
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src_cnt,
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coefs,
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len, pqres,
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dma_flags);
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if (likely(tx))
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break;
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async_tx_quiesce(&submit->depend_tx);
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dma_async_issue_pending(chan);
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}
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|
|
dma_set_unmap(tx, unmap);
|
||
|
|
async_tx_submit(chan, tx, submit);
|
||
|
|
} else {
|
||
|
|
struct page *p_src = P(blocks, disks);
|
||
|
|
struct page *q_src = Q(blocks, disks);
|
||
|
|
enum async_tx_flags flags_orig = submit->flags;
|
||
|
|
dma_async_tx_callback cb_fn_orig = submit->cb_fn;
|
||
|
|
void *scribble = submit->scribble;
|
||
|
|
void *cb_param_orig = submit->cb_param;
|
||
|
|
void *p, *q, *s;
|
||
|
|
|
||
|
|
pr_debug("%s: (sync) disks: %d len: %zu\n",
|
||
|
|
__func__, disks, len);
|
||
|
|
|
||
|
|
/* caller must provide a temporary result buffer and
|
||
|
|
* allow the input parameters to be preserved
|
||
|
|
*/
|
||
|
|
BUG_ON(!spare || !scribble);
|
||
|
|
|
||
|
|
/* wait for any prerequisite operations */
|
||
|
|
async_tx_quiesce(&submit->depend_tx);
|
||
|
|
|
||
|
|
/* recompute p and/or q into the temporary buffer and then
|
||
|
|
* check to see the result matches the current value
|
||
|
|
*/
|
||
|
|
tx = NULL;
|
||
|
|
*pqres = 0;
|
||
|
|
if (p_src) {
|
||
|
|
init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL,
|
||
|
|
NULL, NULL, scribble);
|
||
|
|
tx = async_xor(spare, blocks, offset, disks-2, len, submit);
|
||
|
|
async_tx_quiesce(&tx);
|
||
|
|
p = page_address(p_src) + offset;
|
||
|
|
s = page_address(spare) + offset;
|
||
|
|
*pqres |= !!memcmp(p, s, len) << SUM_CHECK_P;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (q_src) {
|
||
|
|
P(blocks, disks) = NULL;
|
||
|
|
Q(blocks, disks) = spare;
|
||
|
|
init_async_submit(submit, 0, NULL, NULL, NULL, scribble);
|
||
|
|
tx = async_gen_syndrome(blocks, offset, disks, len, submit);
|
||
|
|
async_tx_quiesce(&tx);
|
||
|
|
q = page_address(q_src) + offset;
|
||
|
|
s = page_address(spare) + offset;
|
||
|
|
*pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* restore P, Q and submit */
|
||
|
|
P(blocks, disks) = p_src;
|
||
|
|
Q(blocks, disks) = q_src;
|
||
|
|
|
||
|
|
submit->cb_fn = cb_fn_orig;
|
||
|
|
submit->cb_param = cb_param_orig;
|
||
|
|
submit->flags = flags_orig;
|
||
|
|
async_tx_sync_epilog(submit);
|
||
|
|
tx = NULL;
|
||
|
|
}
|
||
|
|
dmaengine_unmap_put(unmap);
|
||
|
|
|
||
|
|
return tx;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(async_syndrome_val);
|
||
|
|
|
||
|
|
static int __init async_pq_init(void)
|
||
|
|
{
|
||
|
|
pq_scribble_page = alloc_page(GFP_KERNEL);
|
||
|
|
|
||
|
|
if (pq_scribble_page)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
pr_err("%s: failed to allocate required spare page\n", __func__);
|
||
|
|
|
||
|
|
return -ENOMEM;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __exit async_pq_exit(void)
|
||
|
|
{
|
||
|
|
__free_page(pq_scribble_page);
|
||
|
|
}
|
||
|
|
|
||
|
|
module_init(async_pq_init);
|
||
|
|
module_exit(async_pq_exit);
|
||
|
|
|
||
|
|
MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation");
|
||
|
|
MODULE_LICENSE("GPL");
|