524 lines
11 KiB
C
524 lines
11 KiB
C
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/* Copyright (c) 2013 Coraid, Inc. See COPYING for GPL terms. */
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/*
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* aoedev.c
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* AoE device utility functions; maintains device list.
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*/
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#include <linux/hdreg.h>
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#include <linux/blkdev.h>
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#include <linux/netdevice.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/bitmap.h>
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#include <linux/kdev_t.h>
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#include <linux/moduleparam.h>
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#include <linux/string.h>
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#include "aoe.h"
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static void freetgt(struct aoedev *d, struct aoetgt *t);
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static void skbpoolfree(struct aoedev *d);
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static int aoe_dyndevs = 1;
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module_param(aoe_dyndevs, int, 0644);
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MODULE_PARM_DESC(aoe_dyndevs, "Use dynamic minor numbers for devices.");
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static struct aoedev *devlist;
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static DEFINE_SPINLOCK(devlist_lock);
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/* Because some systems will have one, many, or no
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* - partitions,
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* - slots per shelf,
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* - or shelves,
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* we need some flexibility in the way the minor numbers
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* are allocated. So they are dynamic.
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*/
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#define N_DEVS ((1U<<MINORBITS)/AOE_PARTITIONS)
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static DEFINE_SPINLOCK(used_minors_lock);
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static DECLARE_BITMAP(used_minors, N_DEVS);
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static int
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minor_get_dyn(ulong *sysminor)
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{
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ulong flags;
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ulong n;
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int error = 0;
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spin_lock_irqsave(&used_minors_lock, flags);
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n = find_first_zero_bit(used_minors, N_DEVS);
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if (n < N_DEVS)
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set_bit(n, used_minors);
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else
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error = -1;
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spin_unlock_irqrestore(&used_minors_lock, flags);
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*sysminor = n * AOE_PARTITIONS;
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return error;
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}
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static int
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minor_get_static(ulong *sysminor, ulong aoemaj, int aoemin)
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{
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ulong flags;
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ulong n;
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int error = 0;
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enum {
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/* for backwards compatibility when !aoe_dyndevs,
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* a static number of supported slots per shelf */
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NPERSHELF = 16,
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};
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if (aoemin >= NPERSHELF) {
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pr_err("aoe: %s %d slots per shelf\n",
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"static minor device numbers support only",
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NPERSHELF);
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error = -1;
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goto out;
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}
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n = aoemaj * NPERSHELF + aoemin;
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if (n >= N_DEVS) {
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pr_err("aoe: %s with e%ld.%d\n",
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"cannot use static minor device numbers",
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aoemaj, aoemin);
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error = -1;
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goto out;
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}
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spin_lock_irqsave(&used_minors_lock, flags);
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if (test_bit(n, used_minors)) {
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pr_err("aoe: %s %lu\n",
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"existing device already has static minor number",
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n);
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error = -1;
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} else
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set_bit(n, used_minors);
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spin_unlock_irqrestore(&used_minors_lock, flags);
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*sysminor = n * AOE_PARTITIONS;
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out:
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return error;
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}
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static int
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minor_get(ulong *sysminor, ulong aoemaj, int aoemin)
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{
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if (aoe_dyndevs)
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return minor_get_dyn(sysminor);
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else
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return minor_get_static(sysminor, aoemaj, aoemin);
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}
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static void
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minor_free(ulong minor)
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{
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ulong flags;
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minor /= AOE_PARTITIONS;
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BUG_ON(minor >= N_DEVS);
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spin_lock_irqsave(&used_minors_lock, flags);
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BUG_ON(!test_bit(minor, used_minors));
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clear_bit(minor, used_minors);
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spin_unlock_irqrestore(&used_minors_lock, flags);
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}
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/*
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* Users who grab a pointer to the device with aoedev_by_aoeaddr
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* automatically get a reference count and must be responsible
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* for performing a aoedev_put. With the addition of async
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* kthread processing I'm no longer confident that we can
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* guarantee consistency in the face of device flushes.
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*
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* For the time being, we only bother to add extra references for
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* frames sitting on the iocq. When the kthreads finish processing
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* these frames, they will aoedev_put the device.
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*/
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void
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aoedev_put(struct aoedev *d)
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{
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ulong flags;
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spin_lock_irqsave(&devlist_lock, flags);
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d->ref--;
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spin_unlock_irqrestore(&devlist_lock, flags);
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}
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static void
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dummy_timer(struct timer_list *t)
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{
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struct aoedev *d;
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d = from_timer(d, t, timer);
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if (d->flags & DEVFL_TKILL)
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return;
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d->timer.expires = jiffies + HZ;
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add_timer(&d->timer);
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}
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static void
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aoe_failip(struct aoedev *d)
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{
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struct request *rq;
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struct bio *bio;
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unsigned long n;
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aoe_failbuf(d, d->ip.buf);
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rq = d->ip.rq;
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if (rq == NULL)
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return;
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while ((bio = d->ip.nxbio)) {
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bio->bi_status = BLK_STS_IOERR;
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d->ip.nxbio = bio->bi_next;
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n = (unsigned long) rq->special;
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rq->special = (void *) --n;
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}
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if ((unsigned long) rq->special == 0)
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aoe_end_request(d, rq, 0);
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}
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static void
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downdev_frame(struct list_head *pos)
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{
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struct frame *f;
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f = list_entry(pos, struct frame, head);
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list_del(pos);
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if (f->buf) {
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f->buf->nframesout--;
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aoe_failbuf(f->t->d, f->buf);
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}
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aoe_freetframe(f);
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}
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void
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aoedev_downdev(struct aoedev *d)
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{
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struct aoetgt *t, **tt, **te;
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struct list_head *head, *pos, *nx;
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struct request *rq;
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int i;
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d->flags &= ~DEVFL_UP;
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/* clean out active and to-be-retransmitted buffers */
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for (i = 0; i < NFACTIVE; i++) {
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head = &d->factive[i];
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list_for_each_safe(pos, nx, head)
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downdev_frame(pos);
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}
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head = &d->rexmitq;
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list_for_each_safe(pos, nx, head)
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downdev_frame(pos);
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/* reset window dressings */
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tt = d->targets;
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te = tt + d->ntargets;
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for (; tt < te && (t = *tt); tt++) {
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aoecmd_wreset(t);
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t->nout = 0;
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}
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/* clean out the in-process request (if any) */
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aoe_failip(d);
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/* fast fail all pending I/O */
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if (d->blkq) {
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while ((rq = blk_peek_request(d->blkq))) {
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blk_start_request(rq);
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aoe_end_request(d, rq, 1);
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}
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}
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if (d->gd)
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set_capacity(d->gd, 0);
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}
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/* return whether the user asked for this particular
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* device to be flushed
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*/
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static int
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user_req(char *s, size_t slen, struct aoedev *d)
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{
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const char *p;
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size_t lim;
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if (!d->gd)
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return 0;
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p = kbasename(d->gd->disk_name);
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lim = sizeof(d->gd->disk_name);
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lim -= p - d->gd->disk_name;
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if (slen < lim)
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lim = slen;
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return !strncmp(s, p, lim);
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}
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static void
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freedev(struct aoedev *d)
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{
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struct aoetgt **t, **e;
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int freeing = 0;
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unsigned long flags;
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spin_lock_irqsave(&d->lock, flags);
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if (d->flags & DEVFL_TKILL
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&& !(d->flags & DEVFL_FREEING)) {
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d->flags |= DEVFL_FREEING;
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freeing = 1;
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}
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spin_unlock_irqrestore(&d->lock, flags);
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if (!freeing)
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return;
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del_timer_sync(&d->timer);
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if (d->gd) {
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aoedisk_rm_debugfs(d);
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aoedisk_rm_sysfs(d);
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del_gendisk(d->gd);
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put_disk(d->gd);
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blk_cleanup_queue(d->blkq);
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}
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t = d->targets;
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e = t + d->ntargets;
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for (; t < e && *t; t++)
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freetgt(d, *t);
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if (d->bufpool)
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mempool_destroy(d->bufpool);
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skbpoolfree(d);
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minor_free(d->sysminor);
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spin_lock_irqsave(&d->lock, flags);
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d->flags |= DEVFL_FREED;
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spin_unlock_irqrestore(&d->lock, flags);
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}
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enum flush_parms {
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NOT_EXITING = 0,
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EXITING = 1,
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};
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static int
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flush(const char __user *str, size_t cnt, int exiting)
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{
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ulong flags;
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struct aoedev *d, **dd;
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char buf[16];
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int all = 0;
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int specified = 0; /* flush a specific device */
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unsigned int skipflags;
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skipflags = DEVFL_GDALLOC | DEVFL_NEWSIZE | DEVFL_TKILL;
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if (!exiting && cnt >= 3) {
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if (cnt > sizeof buf)
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cnt = sizeof buf;
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if (copy_from_user(buf, str, cnt))
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return -EFAULT;
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all = !strncmp(buf, "all", 3);
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if (!all)
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specified = 1;
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}
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flush_scheduled_work();
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/* pass one: without sleeping, do aoedev_downdev */
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spin_lock_irqsave(&devlist_lock, flags);
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for (d = devlist; d; d = d->next) {
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spin_lock(&d->lock);
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if (exiting) {
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/* unconditionally take each device down */
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} else if (specified) {
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if (!user_req(buf, cnt, d))
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goto cont;
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} else if ((!all && (d->flags & DEVFL_UP))
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|| d->flags & skipflags
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|| d->nopen
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|| d->ref)
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goto cont;
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aoedev_downdev(d);
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d->flags |= DEVFL_TKILL;
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cont:
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spin_unlock(&d->lock);
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}
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spin_unlock_irqrestore(&devlist_lock, flags);
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/* pass two: call freedev, which might sleep,
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* for aoedevs marked with DEVFL_TKILL
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*/
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restart:
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spin_lock_irqsave(&devlist_lock, flags);
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for (d = devlist; d; d = d->next) {
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spin_lock(&d->lock);
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if (d->flags & DEVFL_TKILL
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&& !(d->flags & DEVFL_FREEING)) {
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spin_unlock(&d->lock);
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spin_unlock_irqrestore(&devlist_lock, flags);
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freedev(d);
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goto restart;
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}
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spin_unlock(&d->lock);
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}
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/* pass three: remove aoedevs marked with DEVFL_FREED */
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for (dd = &devlist, d = *dd; d; d = *dd) {
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struct aoedev *doomed = NULL;
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spin_lock(&d->lock);
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if (d->flags & DEVFL_FREED) {
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*dd = d->next;
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doomed = d;
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} else {
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dd = &d->next;
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}
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spin_unlock(&d->lock);
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if (doomed)
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kfree(doomed->targets);
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kfree(doomed);
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}
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spin_unlock_irqrestore(&devlist_lock, flags);
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return 0;
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}
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int
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aoedev_flush(const char __user *str, size_t cnt)
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{
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return flush(str, cnt, NOT_EXITING);
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}
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/* This has been confirmed to occur once with Tms=3*1000 due to the
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* driver changing link and not processing its transmit ring. The
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|
|
* problem is hard enough to solve by returning an error that I'm
|
||
|
|
* still punting on "solving" this.
|
||
|
|
*/
|
||
|
|
static void
|
||
|
|
skbfree(struct sk_buff *skb)
|
||
|
|
{
|
||
|
|
enum { Sms = 250, Tms = 30 * 1000};
|
||
|
|
int i = Tms / Sms;
|
||
|
|
|
||
|
|
if (skb == NULL)
|
||
|
|
return;
|
||
|
|
while (atomic_read(&skb_shinfo(skb)->dataref) != 1 && i-- > 0)
|
||
|
|
msleep(Sms);
|
||
|
|
if (i < 0) {
|
||
|
|
printk(KERN_ERR
|
||
|
|
"aoe: %s holds ref: %s\n",
|
||
|
|
skb->dev ? skb->dev->name : "netif",
|
||
|
|
"cannot free skb -- memory leaked.");
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
skb->truesize -= skb->data_len;
|
||
|
|
skb_shinfo(skb)->nr_frags = skb->data_len = 0;
|
||
|
|
skb_trim(skb, 0);
|
||
|
|
dev_kfree_skb(skb);
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
skbpoolfree(struct aoedev *d)
|
||
|
|
{
|
||
|
|
struct sk_buff *skb, *tmp;
|
||
|
|
|
||
|
|
skb_queue_walk_safe(&d->skbpool, skb, tmp)
|
||
|
|
skbfree(skb);
|
||
|
|
|
||
|
|
__skb_queue_head_init(&d->skbpool);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* find it or allocate it */
|
||
|
|
struct aoedev *
|
||
|
|
aoedev_by_aoeaddr(ulong maj, int min, int do_alloc)
|
||
|
|
{
|
||
|
|
struct aoedev *d;
|
||
|
|
int i;
|
||
|
|
ulong flags;
|
||
|
|
ulong sysminor = 0;
|
||
|
|
|
||
|
|
spin_lock_irqsave(&devlist_lock, flags);
|
||
|
|
|
||
|
|
for (d=devlist; d; d=d->next)
|
||
|
|
if (d->aoemajor == maj && d->aoeminor == min) {
|
||
|
|
spin_lock(&d->lock);
|
||
|
|
if (d->flags & DEVFL_TKILL) {
|
||
|
|
spin_unlock(&d->lock);
|
||
|
|
d = NULL;
|
||
|
|
goto out;
|
||
|
|
}
|
||
|
|
d->ref++;
|
||
|
|
spin_unlock(&d->lock);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
if (d || !do_alloc || minor_get(&sysminor, maj, min) < 0)
|
||
|
|
goto out;
|
||
|
|
d = kcalloc(1, sizeof *d, GFP_ATOMIC);
|
||
|
|
if (!d)
|
||
|
|
goto out;
|
||
|
|
d->targets = kcalloc(NTARGETS, sizeof(*d->targets), GFP_ATOMIC);
|
||
|
|
if (!d->targets) {
|
||
|
|
kfree(d);
|
||
|
|
d = NULL;
|
||
|
|
goto out;
|
||
|
|
}
|
||
|
|
d->ntargets = NTARGETS;
|
||
|
|
INIT_WORK(&d->work, aoecmd_sleepwork);
|
||
|
|
spin_lock_init(&d->lock);
|
||
|
|
skb_queue_head_init(&d->skbpool);
|
||
|
|
timer_setup(&d->timer, dummy_timer, 0);
|
||
|
|
d->timer.expires = jiffies + HZ;
|
||
|
|
add_timer(&d->timer);
|
||
|
|
d->bufpool = NULL; /* defer to aoeblk_gdalloc */
|
||
|
|
d->tgt = d->targets;
|
||
|
|
d->ref = 1;
|
||
|
|
for (i = 0; i < NFACTIVE; i++)
|
||
|
|
INIT_LIST_HEAD(&d->factive[i]);
|
||
|
|
INIT_LIST_HEAD(&d->rexmitq);
|
||
|
|
d->sysminor = sysminor;
|
||
|
|
d->aoemajor = maj;
|
||
|
|
d->aoeminor = min;
|
||
|
|
d->rttavg = RTTAVG_INIT;
|
||
|
|
d->rttdev = RTTDEV_INIT;
|
||
|
|
d->next = devlist;
|
||
|
|
devlist = d;
|
||
|
|
out:
|
||
|
|
spin_unlock_irqrestore(&devlist_lock, flags);
|
||
|
|
return d;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
freetgt(struct aoedev *d, struct aoetgt *t)
|
||
|
|
{
|
||
|
|
struct frame *f;
|
||
|
|
struct list_head *pos, *nx, *head;
|
||
|
|
struct aoeif *ifp;
|
||
|
|
|
||
|
|
for (ifp = t->ifs; ifp < &t->ifs[NAOEIFS]; ++ifp) {
|
||
|
|
if (!ifp->nd)
|
||
|
|
break;
|
||
|
|
dev_put(ifp->nd);
|
||
|
|
}
|
||
|
|
|
||
|
|
head = &t->ffree;
|
||
|
|
list_for_each_safe(pos, nx, head) {
|
||
|
|
list_del(pos);
|
||
|
|
f = list_entry(pos, struct frame, head);
|
||
|
|
skbfree(f->skb);
|
||
|
|
kfree(f);
|
||
|
|
}
|
||
|
|
kfree(t);
|
||
|
|
}
|
||
|
|
|
||
|
|
void
|
||
|
|
aoedev_exit(void)
|
||
|
|
{
|
||
|
|
flush_scheduled_work();
|
||
|
|
flush(NULL, 0, EXITING);
|
||
|
|
}
|
||
|
|
|
||
|
|
int __init
|
||
|
|
aoedev_init(void)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|