aoe: become I/O request queue handler for increased user control
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 <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c
index 3a8f093..7ec4b8f 100644
--- a/drivers/block/aoe/aoeblk.c
+++ b/drivers/block/aoe/aoeblk.c
@@ -161,68 +161,22 @@
}
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;
+ struct request *rq;
- 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);
-
+ 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 @@
{
struct aoedev *d = vp;
struct gendisk *gd;
- enum { KB = 1024, MB = KB * KB, READ_AHEAD = MB, };
+ 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 = READ_AHEAD / 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 @@
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;