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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/block/aoe/aoedev.c
Initial import
Diffstat (limited to 'drivers/block/aoe/aoedev.c')
-rw-r--r--drivers/block/aoe/aoedev.c526
1 files changed, 526 insertions, 0 deletions
diff --git a/drivers/block/aoe/aoedev.c b/drivers/block/aoe/aoedev.c
new file mode 100644
index 000000000..e774c50b6
--- /dev/null
+++ b/drivers/block/aoe/aoedev.c
@@ -0,0 +1,526 @@
+/* Copyright (c) 2013 Coraid, Inc. See COPYING for GPL terms. */
+/*
+ * aoedev.c
+ * AoE device utility functions; maintains device list.
+ */
+
+#include <linux/hdreg.h>
+#include <linux/blkdev.h>
+#include <linux/netdevice.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/bitmap.h>
+#include <linux/kdev_t.h>
+#include <linux/moduleparam.h>
+#include <linux/string.h>
+#include "aoe.h"
+
+static void dummy_timer(ulong);
+static void freetgt(struct aoedev *d, struct aoetgt *t);
+static void skbpoolfree(struct aoedev *d);
+
+static int aoe_dyndevs = 1;
+module_param(aoe_dyndevs, int, 0644);
+MODULE_PARM_DESC(aoe_dyndevs, "Use dynamic minor numbers for devices.");
+
+static struct aoedev *devlist;
+static DEFINE_SPINLOCK(devlist_lock);
+
+/* Because some systems will have one, many, or no
+ * - partitions,
+ * - slots per shelf,
+ * - or shelves,
+ * we need some flexibility in the way the minor numbers
+ * are allocated. So they are dynamic.
+ */
+#define N_DEVS ((1U<<MINORBITS)/AOE_PARTITIONS)
+
+static DEFINE_SPINLOCK(used_minors_lock);
+static DECLARE_BITMAP(used_minors, N_DEVS);
+
+static int
+minor_get_dyn(ulong *sysminor)
+{
+ ulong flags;
+ ulong n;
+ int error = 0;
+
+ spin_lock_irqsave(&used_minors_lock, flags);
+ n = find_first_zero_bit(used_minors, N_DEVS);
+ if (n < N_DEVS)
+ set_bit(n, used_minors);
+ else
+ error = -1;
+ spin_unlock_irqrestore(&used_minors_lock, flags);
+
+ *sysminor = n * AOE_PARTITIONS;
+ return error;
+}
+
+static int
+minor_get_static(ulong *sysminor, ulong aoemaj, int aoemin)
+{
+ ulong flags;
+ ulong n;
+ int error = 0;
+ enum {
+ /* for backwards compatibility when !aoe_dyndevs,
+ * a static number of supported slots per shelf */
+ NPERSHELF = 16,
+ };
+
+ if (aoemin >= NPERSHELF) {
+ pr_err("aoe: %s %d slots per shelf\n",
+ "static minor device numbers support only",
+ NPERSHELF);
+ error = -1;
+ goto out;
+ }
+
+ n = aoemaj * NPERSHELF + aoemin;
+ if (n >= N_DEVS) {
+ pr_err("aoe: %s with e%ld.%d\n",
+ "cannot use static minor device numbers",
+ aoemaj, aoemin);
+ error = -1;
+ goto out;
+ }
+
+ spin_lock_irqsave(&used_minors_lock, flags);
+ if (test_bit(n, used_minors)) {
+ pr_err("aoe: %s %lu\n",
+ "existing device already has static minor number",
+ n);
+ error = -1;
+ } else
+ set_bit(n, used_minors);
+ spin_unlock_irqrestore(&used_minors_lock, flags);
+ *sysminor = n * AOE_PARTITIONS;
+out:
+ return error;
+}
+
+static int
+minor_get(ulong *sysminor, ulong aoemaj, int aoemin)
+{
+ if (aoe_dyndevs)
+ return minor_get_dyn(sysminor);
+ else
+ return minor_get_static(sysminor, aoemaj, aoemin);
+}
+
+static void
+minor_free(ulong minor)
+{
+ ulong flags;
+
+ minor /= AOE_PARTITIONS;
+ BUG_ON(minor >= N_DEVS);
+
+ spin_lock_irqsave(&used_minors_lock, flags);
+ BUG_ON(!test_bit(minor, used_minors));
+ clear_bit(minor, used_minors);
+ spin_unlock_irqrestore(&used_minors_lock, flags);
+}
+
+/*
+ * Users who grab a pointer to the device with aoedev_by_aoeaddr
+ * automatically get a reference count and must be responsible
+ * for performing a aoedev_put. With the addition of async
+ * kthread processing I'm no longer confident that we can
+ * guarantee consistency in the face of device flushes.
+ *
+ * For the time being, we only bother to add extra references for
+ * frames sitting on the iocq. When the kthreads finish processing
+ * these frames, they will aoedev_put the device.
+ */
+
+void
+aoedev_put(struct aoedev *d)
+{
+ ulong flags;
+
+ spin_lock_irqsave(&devlist_lock, flags);
+ d->ref--;
+ spin_unlock_irqrestore(&devlist_lock, flags);
+}
+
+static void
+dummy_timer(ulong vp)
+{
+ struct aoedev *d;
+
+ d = (struct aoedev *)vp;
+ if (d->flags & DEVFL_TKILL)
+ return;
+ d->timer.expires = jiffies + HZ;
+ add_timer(&d->timer);
+}
+
+static void
+aoe_failip(struct aoedev *d)
+{
+ struct request *rq;
+ struct bio *bio;
+ unsigned long n;
+
+ aoe_failbuf(d, d->ip.buf);
+
+ rq = d->ip.rq;
+ if (rq == NULL)
+ return;
+ while ((bio = d->ip.nxbio)) {
+ clear_bit(BIO_UPTODATE, &bio->bi_flags);
+ d->ip.nxbio = bio->bi_next;
+ n = (unsigned long) rq->special;
+ rq->special = (void *) --n;
+ }
+ if ((unsigned long) rq->special == 0)
+ aoe_end_request(d, rq, 0);
+}
+
+static void
+downdev_frame(struct list_head *pos)
+{
+ struct frame *f;
+
+ f = list_entry(pos, struct frame, head);
+ list_del(pos);
+ if (f->buf) {
+ f->buf->nframesout--;
+ aoe_failbuf(f->t->d, f->buf);
+ }
+ aoe_freetframe(f);
+}
+
+void
+aoedev_downdev(struct aoedev *d)
+{
+ struct aoetgt *t, **tt, **te;
+ struct list_head *head, *pos, *nx;
+ struct request *rq;
+ int i;
+
+ d->flags &= ~DEVFL_UP;
+
+ /* clean out active and to-be-retransmitted buffers */
+ for (i = 0; i < NFACTIVE; i++) {
+ head = &d->factive[i];
+ list_for_each_safe(pos, nx, head)
+ downdev_frame(pos);
+ }
+ head = &d->rexmitq;
+ list_for_each_safe(pos, nx, head)
+ downdev_frame(pos);
+
+ /* reset window dressings */
+ tt = d->targets;
+ te = tt + d->ntargets;
+ for (; tt < te && (t = *tt); tt++) {
+ aoecmd_wreset(t);
+ t->nout = 0;
+ }
+
+ /* clean out the in-process request (if any) */
+ aoe_failip(d);
+
+ /* fast fail all pending I/O */
+ if (d->blkq) {
+ while ((rq = blk_peek_request(d->blkq))) {
+ blk_start_request(rq);
+ aoe_end_request(d, rq, 1);
+ }
+ }
+
+ if (d->gd)
+ set_capacity(d->gd, 0);
+}
+
+/* return whether the user asked for this particular
+ * device to be flushed
+ */
+static int
+user_req(char *s, size_t slen, struct aoedev *d)
+{
+ const char *p;
+ size_t lim;
+
+ if (!d->gd)
+ return 0;
+ p = kbasename(d->gd->disk_name);
+ lim = sizeof(d->gd->disk_name);
+ lim -= p - d->gd->disk_name;
+ if (slen < lim)
+ lim = slen;
+
+ return !strncmp(s, p, lim);
+}
+
+static void
+freedev(struct aoedev *d)
+{
+ struct aoetgt **t, **e;
+ int freeing = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&d->lock, flags);
+ if (d->flags & DEVFL_TKILL
+ && !(d->flags & DEVFL_FREEING)) {
+ d->flags |= DEVFL_FREEING;
+ freeing = 1;
+ }
+ spin_unlock_irqrestore(&d->lock, flags);
+ if (!freeing)
+ return;
+
+ del_timer_sync(&d->timer);
+ if (d->gd) {
+ aoedisk_rm_debugfs(d);
+ aoedisk_rm_sysfs(d);
+ del_gendisk(d->gd);
+ put_disk(d->gd);
+ blk_cleanup_queue(d->blkq);
+ }
+ t = d->targets;
+ e = t + d->ntargets;
+ for (; t < e && *t; t++)
+ freetgt(d, *t);
+ if (d->bufpool)
+ mempool_destroy(d->bufpool);
+ skbpoolfree(d);
+ minor_free(d->sysminor);
+
+ spin_lock_irqsave(&d->lock, flags);
+ d->flags |= DEVFL_FREED;
+ spin_unlock_irqrestore(&d->lock, flags);
+}
+
+enum flush_parms {
+ NOT_EXITING = 0,
+ EXITING = 1,
+};
+
+static int
+flush(const char __user *str, size_t cnt, int exiting)
+{
+ ulong flags;
+ struct aoedev *d, **dd;
+ char buf[16];
+ int all = 0;
+ int specified = 0; /* flush a specific device */
+ unsigned int skipflags;
+
+ skipflags = DEVFL_GDALLOC | DEVFL_NEWSIZE | DEVFL_TKILL;
+
+ if (!exiting && cnt >= 3) {
+ if (cnt > sizeof buf)
+ cnt = sizeof buf;
+ if (copy_from_user(buf, str, cnt))
+ return -EFAULT;
+ all = !strncmp(buf, "all", 3);
+ if (!all)
+ specified = 1;
+ }
+
+ flush_scheduled_work();
+ /* pass one: without sleeping, do aoedev_downdev */
+ spin_lock_irqsave(&devlist_lock, flags);
+ for (d = devlist; d; d = d->next) {
+ spin_lock(&d->lock);
+ if (exiting) {
+ /* unconditionally take each device down */
+ } else if (specified) {
+ if (!user_req(buf, cnt, d))
+ goto cont;
+ } else if ((!all && (d->flags & DEVFL_UP))
+ || d->flags & skipflags
+ || d->nopen
+ || d->ref)
+ goto cont;
+
+ aoedev_downdev(d);
+ d->flags |= DEVFL_TKILL;
+cont:
+ spin_unlock(&d->lock);
+ }
+ spin_unlock_irqrestore(&devlist_lock, flags);
+
+ /* pass two: call freedev, which might sleep,
+ * for aoedevs marked with DEVFL_TKILL
+ */
+restart:
+ spin_lock_irqsave(&devlist_lock, flags);
+ for (d = devlist; d; d = d->next) {
+ spin_lock(&d->lock);
+ if (d->flags & DEVFL_TKILL
+ && !(d->flags & DEVFL_FREEING)) {
+ spin_unlock(&d->lock);
+ spin_unlock_irqrestore(&devlist_lock, flags);
+ freedev(d);
+ goto restart;
+ }
+ spin_unlock(&d->lock);
+ }
+
+ /* pass three: remove aoedevs marked with DEVFL_FREED */
+ for (dd = &devlist, d = *dd; d; d = *dd) {
+ struct aoedev *doomed = NULL;
+
+ spin_lock(&d->lock);
+ if (d->flags & DEVFL_FREED) {
+ *dd = d->next;
+ doomed = d;
+ } else {
+ dd = &d->next;
+ }
+ spin_unlock(&d->lock);
+ if (doomed)
+ kfree(doomed->targets);
+ kfree(doomed);
+ }
+ spin_unlock_irqrestore(&devlist_lock, flags);
+
+ return 0;
+}
+
+int
+aoedev_flush(const char __user *str, size_t cnt)
+{
+ return flush(str, cnt, NOT_EXITING);
+}
+
+/* This has been confirmed to occur once with Tms=3*1000 due to the
+ * driver changing link and not processing its transmit ring. The
+ * 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);
+ init_timer(&d->timer);
+ d->timer.data = (ulong) d;
+ d->timer.function = dummy_timer;
+ 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;
+}