Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934236Ab2HWSpO (ORCPT ); Thu, 23 Aug 2012 14:45:14 -0400 Received: from noserose.net ([66.220.18.76]:39189 "HELO noserose.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S934182Ab2HWSoo (ORCPT ); Thu, 23 Aug 2012 14:44:44 -0400 Message-Id: <268e1bd3b1d3369a68d09425ed5e9bca1ad38262.1345743801.git.ecashin@coraid.com> In-Reply-To: References: From: Ed Cashin Date: Fri, 17 Aug 2012 21:26:29 -0400 Subject: [PATCH 03/14] aoe: become I/O request queue handler for increased user control To: Andrew Morton Cc: linux-kernel@vger.kernel.org, ecashin@coraid.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 24731 Lines: 971 To allow users to choose an elevator algorithm for their particular workloads, change from a make_request-style driver to an I/O-request-queue-handler-style driver. We have to do a couple of things that might be surprising. We manipulate the page _count directly on the assumption that we still have no guarantee that users of the block layer are prohibited from submitting bios containing pages with zero reference counts.[1] If such a prohibition now exists, I can get rid of the _count manipulation. Just as before this patch, we still keep track of the sk_buffs that the network layer still hasn't finished yet and cap the resources we use with a "pool" of skbs.[2] Now that the block layer maintains the disk stats, the aoe driver's diskstats function can go away. 1. https://lkml.org/lkml/2007/3/1/374 2. https://lkml.org/lkml/2007/7/6/241 Signed-off-by: Ed Cashin --- drivers/block/aoe/aoe.h | 26 ++-- drivers/block/aoe/aoeblk.c | 88 ++++---------- drivers/block/aoe/aoechr.c | 1 + drivers/block/aoe/aoecmd.c | 282 +++++++++++++++++++++++++++++++------------ drivers/block/aoe/aoedev.c | 93 ++++++++++----- 5 files changed, 308 insertions(+), 182 deletions(-) diff --git a/drivers/block/aoe/aoe.h b/drivers/block/aoe/aoe.h index 0cd6c0f..8c4f6d9 100644 --- a/drivers/block/aoe/aoe.h +++ b/drivers/block/aoe/aoe.h @@ -90,7 +90,7 @@ enum { MIN_BUFS = 16, NTARGETS = 8, NAOEIFS = 8, - NSKBPOOLMAX = 128, + NSKBPOOLMAX = 256, NFACTIVE = 17, TIMERTICK = HZ / 10, @@ -100,30 +100,26 @@ enum { }; struct buf { - struct list_head bufs; - ulong stime; /* for disk stats */ - ulong flags; ulong nframesout; ulong resid; ulong bv_resid; - ulong bv_off; sector_t sector; struct bio *bio; struct bio_vec *bv; + struct request *rq; }; struct frame { struct list_head head; u32 tag; ulong waited; - struct buf *buf; struct aoetgt *t; /* parent target I belong to */ - char *bufaddr; - ulong bcnt; sector_t lba; struct sk_buff *skb; /* command skb freed on module exit */ struct sk_buff *r_skb; /* response skb for async processing */ + struct buf *buf; struct bio_vec *bv; + ulong bcnt; ulong bv_off; }; @@ -161,6 +157,7 @@ struct aoedev { u16 rttavg; /* round trip average of requests/responses */ u16 mintimer; u16 fw_ver; /* version of blade's firmware */ + ulong ref; struct work_struct work;/* disk create work struct */ struct gendisk *gd; struct request_queue *blkq; @@ -168,11 +165,13 @@ struct aoedev { sector_t ssize; struct timer_list timer; spinlock_t lock; - struct sk_buff_head sendq; struct sk_buff_head skbpool; mempool_t *bufpool; /* for deadlock-free Buf allocation */ - struct list_head bufq; /* queue of bios to work on */ - struct buf *inprocess; /* the one we're currently working on */ + struct { /* pointers to work in progress */ + struct buf *buf; + struct bio *nxbio; + struct request *rq; + } ip; struct aoetgt *targets[NTARGETS]; struct aoetgt **tgt; /* target in use when working */ struct aoetgt *htgt; /* target needing rexmit assistance */ @@ -209,6 +208,8 @@ void aoecmd_exit(void); int aoecmd_init(void); struct sk_buff *aoecmd_ata_id(struct aoedev *); void aoe_freetframe(struct frame *); +void aoe_flush_iocq(void); +void aoe_end_request(struct aoedev *, struct request *, int); int aoedev_init(void); void aoedev_exit(void); @@ -216,7 +217,8 @@ struct aoedev *aoedev_by_aoeaddr(int maj, int min); struct aoedev *aoedev_by_sysminor_m(ulong sysminor); void aoedev_downdev(struct aoedev *d); int aoedev_flush(const char __user *str, size_t size); -void aoe_failbuf(struct aoedev *d, struct buf *buf); +void aoe_failbuf(struct aoedev *, struct buf *); +void aoedev_put(struct aoedev *); int aoenet_init(void); void aoenet_exit(void); diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c index 1471f81..7ec4b8f 100644 --- a/drivers/block/aoe/aoeblk.c +++ b/drivers/block/aoe/aoeblk.c @@ -161,68 +161,22 @@ aoeblk_release(struct gendisk *disk, fmode_t mode) } static void -aoeblk_make_request(struct request_queue *q, struct bio *bio) +aoeblk_request(struct request_queue *q) { - struct sk_buff_head queue; struct aoedev *d; - struct buf *buf; - ulong flags; - - blk_queue_bounce(q, &bio); - - if (bio == NULL) { - printk(KERN_ERR "aoe: bio is NULL\n"); - BUG(); - return; - } - d = bio->bi_bdev->bd_disk->private_data; - if (d == NULL) { - printk(KERN_ERR "aoe: bd_disk->private_data is NULL\n"); - BUG(); - bio_endio(bio, -ENXIO); - return; - } else if (bio->bi_io_vec == NULL) { - printk(KERN_ERR "aoe: bi_io_vec is NULL\n"); - BUG(); - bio_endio(bio, -ENXIO); - return; - } - buf = mempool_alloc(d->bufpool, GFP_NOIO); - if (buf == NULL) { - printk(KERN_INFO "aoe: buf allocation failure\n"); - bio_endio(bio, -ENOMEM); - return; - } - memset(buf, 0, sizeof(*buf)); - INIT_LIST_HEAD(&buf->bufs); - buf->stime = jiffies; - buf->bio = bio; - buf->resid = bio->bi_size; - buf->sector = bio->bi_sector; - buf->bv = &bio->bi_io_vec[bio->bi_idx]; - buf->bv_resid = buf->bv->bv_len; - WARN_ON(buf->bv_resid == 0); - buf->bv_off = buf->bv->bv_offset; - - spin_lock_irqsave(&d->lock, flags); + struct request *rq; + d = q->queuedata; if ((d->flags & DEVFL_UP) == 0) { pr_info_ratelimited("aoe: device %ld.%d is not up\n", d->aoemajor, d->aoeminor); - spin_unlock_irqrestore(&d->lock, flags); - mempool_free(buf, d->bufpool); - bio_endio(bio, -ENXIO); + while ((rq = blk_peek_request(q))) { + blk_start_request(rq); + aoe_end_request(d, rq, 1); + } return; } - - list_add_tail(&buf->bufs, &d->bufq); - aoecmd_work(d); - __skb_queue_head_init(&queue); - skb_queue_splice_init(&d->sendq, &queue); - - spin_unlock_irqrestore(&d->lock, flags); - aoenet_xmit(&queue); } static int @@ -254,34 +208,46 @@ aoeblk_gdalloc(void *vp) { struct aoedev *d = vp; struct gendisk *gd; + mempool_t *mp; + struct request_queue *q; + enum { KB = 1024, MB = KB * KB, READ_AHEAD = 2 * MB, }; ulong flags; gd = alloc_disk(AOE_PARTITIONS); if (gd == NULL) { - printk(KERN_ERR - "aoe: cannot allocate disk structure for %ld.%d\n", + pr_err("aoe: cannot allocate disk structure for %ld.%d\n", d->aoemajor, d->aoeminor); goto err; } - d->bufpool = mempool_create_slab_pool(MIN_BUFS, buf_pool_cache); - if (d->bufpool == NULL) { + mp = mempool_create(MIN_BUFS, mempool_alloc_slab, mempool_free_slab, + buf_pool_cache); + if (mp == NULL) { printk(KERN_ERR "aoe: cannot allocate bufpool for %ld.%d\n", d->aoemajor, d->aoeminor); goto err_disk; } + q = blk_init_queue(aoeblk_request, &d->lock); + if (q == NULL) { + pr_err("aoe: cannot allocate block queue for %ld.%d\n", + d->aoemajor, d->aoeminor); + mempool_destroy(mp); + goto err_disk; + } d->blkq = blk_alloc_queue(GFP_KERNEL); if (!d->blkq) goto err_mempool; - blk_queue_make_request(d->blkq, aoeblk_make_request); d->blkq->backing_dev_info.name = "aoe"; if (bdi_init(&d->blkq->backing_dev_info)) goto err_blkq; spin_lock_irqsave(&d->lock, flags); blk_queue_max_hw_sectors(d->blkq, BLK_DEF_MAX_SECTORS); - d->blkq->backing_dev_info.ra_pages = BLK_DEF_MAX_SECTORS * 1024; - d->blkq->backing_dev_info.ra_pages /= PAGE_CACHE_SIZE; + q->backing_dev_info.ra_pages = READ_AHEAD / PAGE_CACHE_SIZE; + d->bufpool = mp; + d->blkq = gd->queue = q; + q->queuedata = d; + d->gd = gd; gd->major = AOE_MAJOR; gd->first_minor = d->sysminor * AOE_PARTITIONS; gd->fops = &aoe_bdops; @@ -290,8 +256,6 @@ aoeblk_gdalloc(void *vp) snprintf(gd->disk_name, sizeof gd->disk_name, "etherd/e%ld.%d", d->aoemajor, d->aoeminor); - gd->queue = d->blkq; - d->gd = gd; d->flags &= ~DEVFL_GDALLOC; d->flags |= DEVFL_UP; diff --git a/drivers/block/aoe/aoechr.c b/drivers/block/aoe/aoechr.c index f145388..3557f0d 100644 --- a/drivers/block/aoe/aoechr.c +++ b/drivers/block/aoe/aoechr.c @@ -106,6 +106,7 @@ loop: spin_lock_irqsave(&d->lock, flags); goto loop; } + aoedev_put(d); if (skb) { struct sk_buff_head queue; __skb_queue_head_init(&queue); diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c index d0fc53f..e7df343 100644 --- a/drivers/block/aoe/aoecmd.c +++ b/drivers/block/aoe/aoecmd.c @@ -23,6 +23,8 @@ static void ktcomplete(struct frame *, struct sk_buff *); +static struct buf *nextbuf(struct aoedev *); + static int aoe_deadsecs = 60 * 3; module_param(aoe_deadsecs, int, 0644); MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev."); @@ -282,17 +284,20 @@ aoecmd_ata_rw(struct aoedev *d) struct bio_vec *bv; struct aoetgt *t; struct sk_buff *skb; + struct sk_buff_head queue; ulong bcnt, fbcnt; char writebit, extbit; writebit = 0x10; extbit = 0x4; + buf = nextbuf(d); + if (buf == NULL) + return 0; f = newframe(d); if (f == NULL) return 0; t = *d->tgt; - buf = d->inprocess; bv = buf->bv; bcnt = t->ifp->maxbcnt; if (bcnt == 0) @@ -311,7 +316,7 @@ aoecmd_ata_rw(struct aoedev *d) fbcnt -= buf->bv_resid; buf->resid -= buf->bv_resid; if (buf->resid == 0) { - d->inprocess = NULL; + d->ip.buf = NULL; break; } buf->bv++; @@ -363,8 +368,11 @@ aoecmd_ata_rw(struct aoedev *d) skb->dev = t->ifp->nd; skb = skb_clone(skb, GFP_ATOMIC); - if (skb) - __skb_queue_tail(&d->sendq, skb); + if (skb) { + __skb_queue_head_init(&queue); + __skb_queue_tail(&queue, skb); + aoenet_xmit(&queue); + } return 1; } @@ -414,6 +422,7 @@ static void resend(struct aoedev *d, struct frame *f) { struct sk_buff *skb; + struct sk_buff_head queue; struct aoe_hdr *h; struct aoe_atahdr *ah; struct aoetgt *t; @@ -443,7 +452,9 @@ resend(struct aoedev *d, struct frame *f) skb = skb_clone(skb, GFP_ATOMIC); if (skb == NULL) return; - __skb_queue_tail(&d->sendq, skb); + __skb_queue_head_init(&queue); + __skb_queue_tail(&queue, skb); + aoenet_xmit(&queue); } static int @@ -553,7 +564,6 @@ ata_scnt(unsigned char *packet) { static void rexmit_timer(ulong vp) { - struct sk_buff_head queue; struct aoedev *d; struct aoetgt *t, **tt, **te; struct aoeif *ifp; @@ -602,6 +612,12 @@ rexmit_timer(ulong vp) } } + if (!list_empty(&flist)) { /* retransmissions necessary */ + n = d->rttavg <<= 1; + if (n > MAXTIMER) + d->rttavg = MAXTIMER; + } + /* process expired frames */ while (!list_empty(&flist)) { pos = flist.next; @@ -640,45 +656,131 @@ rexmit_timer(ulong vp) resend(d, f); } - if (!skb_queue_empty(&d->sendq)) { - n = d->rttavg <<= 1; - if (n > MAXTIMER) - d->rttavg = MAXTIMER; - } - - if (d->flags & DEVFL_KICKME || d->htgt) { + if ((d->flags & DEVFL_KICKME || d->htgt) && d->blkq) { d->flags &= ~DEVFL_KICKME; - aoecmd_work(d); + d->blkq->request_fn(d->blkq); } - __skb_queue_head_init(&queue); - skb_queue_splice_init(&d->sendq, &queue); - d->timer.expires = jiffies + TIMERTICK; add_timer(&d->timer); spin_unlock_irqrestore(&d->lock, flags); +} - aoenet_xmit(&queue); +static unsigned long +rqbiocnt(struct request *r) +{ + struct bio *bio; + unsigned long n = 0; + + __rq_for_each_bio(bio, r) + n++; + return n; +} + +/* This can be removed if we are certain that no users of the block + * layer will ever use zero-count pages in bios. Otherwise we have to + * protect against the put_page sometimes done by the network layer. + * + * See http://oss.sgi.com/archives/xfs/2007-01/msg00594.html for + * discussion. + * + * We cannot use get_page in the workaround, because it insists on a + * positive page count as a precondition. So we use _count directly. + */ +static void +bio_pageinc(struct bio *bio) +{ + struct bio_vec *bv; + struct page *page; + int i; + + bio_for_each_segment(bv, bio, i) { + page = bv->bv_page; + /* Non-zero page count for non-head members of + * compound pages is no longer allowed by the kernel, + * but this has never been seen here. + */ + if (unlikely(PageCompound(page))) + if (compound_trans_head(page) != page) { + pr_crit("page tail used for block I/O\n"); + BUG(); + } + atomic_inc(&page->_count); + } +} + +static void +bio_pagedec(struct bio *bio) +{ + struct bio_vec *bv; + int i; + + bio_for_each_segment(bv, bio, i) + atomic_dec(&bv->bv_page->_count); +} + +static void +bufinit(struct buf *buf, struct request *rq, struct bio *bio) +{ + struct bio_vec *bv; + + memset(buf, 0, sizeof(*buf)); + buf->rq = rq; + buf->bio = bio; + buf->resid = bio->bi_size; + buf->sector = bio->bi_sector; + bio_pageinc(bio); + buf->bv = bv = &bio->bi_io_vec[bio->bi_idx]; + buf->bv_resid = bv->bv_len; + WARN_ON(buf->bv_resid == 0); +} + +static struct buf * +nextbuf(struct aoedev *d) +{ + struct request *rq; + struct request_queue *q; + struct buf *buf; + struct bio *bio; + + q = d->blkq; + if (q == NULL) + return NULL; /* initializing */ + if (d->ip.buf) + return d->ip.buf; + rq = d->ip.rq; + if (rq == NULL) { + rq = blk_peek_request(q); + if (rq == NULL) + return NULL; + blk_start_request(rq); + d->ip.rq = rq; + d->ip.nxbio = rq->bio; + rq->special = (void *) rqbiocnt(rq); + } + buf = mempool_alloc(d->bufpool, GFP_ATOMIC); + if (buf == NULL) { + pr_err("aoe: nextbuf: unable to mempool_alloc!\n"); + return NULL; + } + bio = d->ip.nxbio; + bufinit(buf, rq, bio); + bio = bio->bi_next; + d->ip.nxbio = bio; + if (bio == NULL) + d->ip.rq = NULL; + return d->ip.buf = buf; } /* enters with d->lock held */ void aoecmd_work(struct aoedev *d) { - struct buf *buf; -loop: if (d->htgt && !sthtith(d)) return; - if (d->inprocess == NULL) { - if (list_empty(&d->bufq)) - return; - buf = container_of(d->bufq.next, struct buf, bufs); - list_del(d->bufq.next); - d->inprocess = buf; - } - if (aoecmd_ata_rw(d)) - goto loop; + while (aoecmd_ata_rw(d)) + ; } /* this function performs work that has been deferred until sleeping is OK @@ -801,25 +903,6 @@ gettgt(struct aoedev *d, char *addr) return NULL; } -static inline void -diskstats(struct gendisk *disk, struct bio *bio, ulong duration, sector_t sector) -{ - unsigned long n_sect = bio->bi_size >> 9; - const int rw = bio_data_dir(bio); - struct hd_struct *part; - int cpu; - - cpu = part_stat_lock(); - part = disk_map_sector_rcu(disk, sector); - - part_stat_inc(cpu, part, ios[rw]); - part_stat_add(cpu, part, ticks[rw], duration); - part_stat_add(cpu, part, sectors[rw], n_sect); - part_stat_add(cpu, part, io_ticks, duration); - - part_stat_unlock(); -} - static void bvcpy(struct bio_vec *bv, ulong off, struct sk_buff *skb, long cnt) { @@ -841,6 +924,43 @@ loop: goto loop; } +void +aoe_end_request(struct aoedev *d, struct request *rq, int fastfail) +{ + struct bio *bio; + int bok; + struct request_queue *q; + + q = d->blkq; + if (rq == d->ip.rq) + d->ip.rq = NULL; + do { + bio = rq->bio; + bok = !fastfail && test_bit(BIO_UPTODATE, &bio->bi_flags); + } while (__blk_end_request(rq, bok ? 0 : -EIO, bio->bi_size)); + + /* cf. http://lkml.org/lkml/2006/10/31/28 */ + if (!fastfail) + q->request_fn(q); +} + +static void +aoe_end_buf(struct aoedev *d, struct buf *buf) +{ + struct request *rq; + unsigned long n; + + if (buf == d->ip.buf) + d->ip.buf = NULL; + rq = buf->rq; + bio_pagedec(buf->bio); + mempool_free(buf, d->bufpool); + n = (unsigned long) rq->special; + rq->special = (void *) --n; + if (n == 0) + aoe_end_request(d, rq, 0); +} + static void ktiocomplete(struct frame *f) { @@ -875,7 +995,7 @@ ktiocomplete(struct frame *f) ahout->cmdstat, ahin->cmdstat, d->aoemajor, d->aoeminor); noskb: if (buf) - buf->flags |= BUFFL_FAIL; + clear_bit(BIO_UPTODATE, &buf->bio->bi_flags); goto badrsp; } @@ -886,7 +1006,7 @@ noskb: if (buf) if (skb->len < n) { pr_err("aoe: runt data size in read. skb->len=%d need=%ld\n", skb->len, n); - buf->flags |= BUFFL_FAIL; + clear_bit(BIO_UPTODATE, &buf->bio->bi_flags); break; } bvcpy(f->bv, f->bv_off, skb, n); @@ -926,18 +1046,13 @@ badrsp: aoe_freetframe(f); - if (buf && --buf->nframesout == 0 && buf->resid == 0) { - struct bio *bio = buf->bio; + if (buf && --buf->nframesout == 0 && buf->resid == 0) + aoe_end_buf(d, buf); - diskstats(d->gd, bio, jiffies - buf->stime, buf->sector); - n = (buf->flags & BUFFL_FAIL) ? -EIO : 0; - mempool_free(buf, d->bufpool); - spin_unlock_irq(&d->lock); - if (n != -EIO) - bio_flush_dcache_pages(buf->bio); - bio_endio(bio, n); - } else - spin_unlock_irq(&d->lock); + aoecmd_work(d); + + spin_unlock_irq(&d->lock); + aoedev_put(d); dev_kfree_skb(skb); } @@ -1068,12 +1183,14 @@ aoecmd_ata_rsp(struct sk_buff *skb) printk(KERN_INFO "aoe: can't find target e%ld.%d:%pm\n", d->aoemajor, d->aoeminor, h->src); spin_unlock_irqrestore(&d->lock, flags); + aoedev_put(d); return skb; } f = getframe(t, n); if (f == NULL) { calc_rttavg(d, -tsince(n)); spin_unlock_irqrestore(&d->lock, flags); + aoedev_put(d); snprintf(ebuf, sizeof ebuf, "%15s e%d.%d tag=%08x@%08lx\n", "unexpected rsp", @@ -1193,8 +1310,10 @@ aoecmd_cfg_rsp(struct sk_buff *skb) struct aoeif *ifp; ulong flags, sysminor, aoemajor; struct sk_buff *sl; + struct sk_buff_head queue; u16 n; + sl = NULL; h = (struct aoe_hdr *) skb_mac_header(skb); ch = (struct aoe_cfghdr *) (h+1); @@ -1231,10 +1350,8 @@ aoecmd_cfg_rsp(struct sk_buff *skb) t = gettgt(d, h->src); if (!t) { t = addtgt(d, h->src, n); - if (!t) { - spin_unlock_irqrestore(&d->lock, flags); - return; - } + if (!t) + goto bail; } ifp = getif(t, skb->dev); if (!ifp) { @@ -1243,8 +1360,7 @@ aoecmd_cfg_rsp(struct sk_buff *skb) printk(KERN_INFO "aoe: device addif failure; " "too many interfaces?\n"); - spin_unlock_irqrestore(&d->lock, flags); - return; + goto bail; } } if (ifp->maxbcnt) { @@ -1265,18 +1381,14 @@ aoecmd_cfg_rsp(struct sk_buff *skb) } /* don't change users' perspective */ - if (d->nopen) { - spin_unlock_irqrestore(&d->lock, flags); - return; + if (d->nopen == 0) { + d->fw_ver = be16_to_cpu(ch->fwver); + sl = aoecmd_ata_id(d); } - d->fw_ver = be16_to_cpu(ch->fwver); - - sl = aoecmd_ata_id(d); - +bail: spin_unlock_irqrestore(&d->lock, flags); - + aoedev_put(d); if (sl) { - struct sk_buff_head queue; __skb_queue_head_init(&queue); __skb_queue_tail(&queue, sl); aoenet_xmit(&queue); @@ -1305,8 +1417,19 @@ aoecmd_cleanslate(struct aoedev *d) } } -static void -flush_iocq(void) +void +aoe_failbuf(struct aoedev *d, struct buf *buf) +{ + if (buf == NULL) + return; + buf->resid = 0; + clear_bit(BIO_UPTODATE, &buf->bio->bi_flags); + if (buf->nframesout == 0) + aoe_end_buf(d, buf); +} + +void +aoe_flush_iocq(void) { struct frame *f; struct aoedev *d; @@ -1332,6 +1455,7 @@ flush_iocq(void) aoe_freetframe(f); spin_unlock_irqrestore(&d->lock, flags); dev_kfree_skb(skb); + aoedev_put(d); } } @@ -1352,5 +1476,5 @@ void aoecmd_exit(void) { aoe_ktstop(&kts); - flush_iocq(); + aoe_flush_iocq(); } diff --git a/drivers/block/aoe/aoedev.c b/drivers/block/aoe/aoedev.c index 40bae1a..635dc98 100644 --- a/drivers/block/aoe/aoedev.c +++ b/drivers/block/aoe/aoedev.c @@ -19,6 +19,17 @@ static void skbpoolfree(struct aoedev *d); static struct aoedev *devlist; static DEFINE_SPINLOCK(devlist_lock); +/* + * Users who grab a pointer to the device with aoedev_by_aoeaddr or + * aoedev_by_sysminor_m 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. + */ struct aoedev * aoedev_by_aoeaddr(int maj, int min) { @@ -28,13 +39,25 @@ aoedev_by_aoeaddr(int maj, int min) spin_lock_irqsave(&devlist_lock, flags); for (d=devlist; d; d=d->next) - if (d->aoemajor == maj && d->aoeminor == min) + if (d->aoemajor == maj && d->aoeminor == min) { + d->ref++; break; + } spin_unlock_irqrestore(&devlist_lock, flags); return d; } +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) { @@ -47,21 +70,26 @@ dummy_timer(ulong vp) add_timer(&d->timer); } -void -aoe_failbuf(struct aoedev *d, struct buf *buf) +static void +aoe_failip(struct aoedev *d) { + struct request *rq; struct bio *bio; + unsigned long n; + + aoe_failbuf(d, d->ip.buf); - if (buf == NULL) + rq = d->ip.rq; + if (rq == NULL) return; - buf->flags |= BUFFL_FAIL; - if (buf->nframesout == 0) { - if (buf == d->inprocess) /* ensure we only process this once */ - d->inprocess = NULL; - bio = buf->bio; - mempool_free(buf, d->bufpool); - bio_endio(bio, -EIO); + 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); } void @@ -70,8 +98,11 @@ aoedev_downdev(struct aoedev *d) struct aoetgt *t, **tt, **te; struct frame *f; struct list_head *head, *pos, *nx; + struct request *rq; int i; + d->flags &= ~DEVFL_UP; + /* clean out active buffers on all targets */ tt = d->targets; te = tt + NTARGETS; @@ -92,22 +123,20 @@ aoedev_downdev(struct aoedev *d) t->nout = 0; } - /* clean out the in-process buffer (if any) */ - aoe_failbuf(d, d->inprocess); - d->inprocess = NULL; + /* clean out the in-process request (if any) */ + aoe_failip(d); d->htgt = NULL; - /* clean out all pending I/O */ - while (!list_empty(&d->bufq)) { - struct buf *buf = container_of(d->bufq.next, struct buf, bufs); - list_del(d->bufq.next); - aoe_failbuf(d, buf); + /* 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); - - d->flags &= ~DEVFL_UP; } static void @@ -120,6 +149,7 @@ aoedev_freedev(struct aoedev *d) aoedisk_rm_sysfs(d); del_gendisk(d->gd); put_disk(d->gd); + blk_cleanup_queue(d->blkq); } t = d->targets; e = t + NTARGETS; @@ -128,7 +158,6 @@ aoedev_freedev(struct aoedev *d) if (d->bufpool) mempool_destroy(d->bufpool); skbpoolfree(d); - blk_cleanup_queue(d->blkq); kfree(d); } @@ -155,7 +184,8 @@ aoedev_flush(const char __user *str, size_t cnt) spin_lock(&d->lock); if ((!all && (d->flags & DEVFL_UP)) || (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE)) - || d->nopen) { + || d->nopen + || d->ref) { spin_unlock(&d->lock); dd = &d->next; continue; @@ -176,12 +206,15 @@ aoedev_flush(const char __user *str, size_t cnt) return 0; } -/* I'm not really sure that this is a realistic problem, but if the -network driver goes gonzo let's just leak memory after complaining. */ +/* 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 = 100, Tms = 3*1000}; + enum { Sms = 250, Tms = 30 * 1000}; int i = Tms / Sms; if (skb == NULL) @@ -222,8 +255,10 @@ aoedev_by_sysminor_m(ulong sysminor) spin_lock_irqsave(&devlist_lock, flags); for (d=devlist; d; d=d->next) - if (d->sysminor == sysminor) + if (d->sysminor == sysminor) { + d->ref++; break; + } if (d) goto out; d = kcalloc(1, sizeof *d, GFP_ATOMIC); @@ -231,7 +266,6 @@ aoedev_by_sysminor_m(ulong sysminor) goto out; INIT_WORK(&d->work, aoecmd_sleepwork); spin_lock_init(&d->lock); - skb_queue_head_init(&d->sendq); skb_queue_head_init(&d->skbpool); init_timer(&d->timer); d->timer.data = (ulong) d; @@ -240,7 +274,7 @@ aoedev_by_sysminor_m(ulong sysminor) add_timer(&d->timer); d->bufpool = NULL; /* defer to aoeblk_gdalloc */ d->tgt = d->targets; - INIT_LIST_HEAD(&d->bufq); + d->ref = 1; d->sysminor = sysminor; d->aoemajor = AOEMAJOR(sysminor); d->aoeminor = AOEMINOR(sysminor); @@ -274,6 +308,7 @@ aoedev_exit(void) struct aoedev *d; ulong flags; + aoe_flush_iocq(); while ((d = devlist)) { devlist = d->next; -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/