vdev_disk: use bio_chain() to submit multiple BIOs

Simplifies our code a lot, so we don't have to wait for each and
reassemble them.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Closes 
Closes 
This commit is contained in:
Rob Norris 2024-02-21 11:07:21 +11:00 committed by Brian Behlendorf
parent df2169d141
commit 72fd834c47
1 changed files with 92 additions and 163 deletions
module/os/linux/zfs

View File

@ -454,10 +454,9 @@ vdev_disk_close(vdev_t *v)
if (v->vdev_reopening || vd == NULL) if (v->vdev_reopening || vd == NULL)
return; return;
if (vd->vd_bdh != NULL) { if (vd->vd_bdh != NULL)
vdev_blkdev_put(vd->vd_bdh, spa_mode(v->vdev_spa), vdev_blkdev_put(vd->vd_bdh, spa_mode(v->vdev_spa),
zfs_vdev_holder); zfs_vdev_holder);
}
rw_destroy(&vd->vd_lock); rw_destroy(&vd->vd_lock);
kmem_free(vd, sizeof (vdev_disk_t)); kmem_free(vd, sizeof (vdev_disk_t));
@ -663,9 +662,6 @@ typedef struct {
abd_t *vbio_abd; /* abd carrying borrowed linear buf */ abd_t *vbio_abd; /* abd carrying borrowed linear buf */
atomic_t vbio_ref; /* bio refcount */
int vbio_error; /* error from failed bio */
uint_t vbio_max_segs; /* max segs per bio */ uint_t vbio_max_segs; /* max segs per bio */
uint_t vbio_max_bytes; /* max bytes per bio */ uint_t vbio_max_bytes; /* max bytes per bio */
@ -674,43 +670,52 @@ typedef struct {
uint64_t vbio_offset; /* start offset of next bio */ uint64_t vbio_offset; /* start offset of next bio */
struct bio *vbio_bio; /* pointer to the current bio */ struct bio *vbio_bio; /* pointer to the current bio */
struct bio *vbio_bios; /* list of all bios */ int vbio_flags; /* bio flags */
} vbio_t; } vbio_t;
static vbio_t * static vbio_t *
vbio_alloc(zio_t *zio, struct block_device *bdev) vbio_alloc(zio_t *zio, struct block_device *bdev, int flags)
{ {
vbio_t *vbio = kmem_zalloc(sizeof (vbio_t), KM_SLEEP); vbio_t *vbio = kmem_zalloc(sizeof (vbio_t), KM_SLEEP);
vbio->vbio_zio = zio; vbio->vbio_zio = zio;
vbio->vbio_bdev = bdev; vbio->vbio_bdev = bdev;
atomic_set(&vbio->vbio_ref, 0); vbio->vbio_abd = NULL;
vbio->vbio_max_segs = vdev_bio_max_segs(bdev); vbio->vbio_max_segs = vdev_bio_max_segs(bdev);
vbio->vbio_max_bytes = vdev_bio_max_bytes(bdev); vbio->vbio_max_bytes = vdev_bio_max_bytes(bdev);
vbio->vbio_lbs_mask = ~(bdev_logical_block_size(bdev)-1); vbio->vbio_lbs_mask = ~(bdev_logical_block_size(bdev)-1);
vbio->vbio_offset = zio->io_offset; vbio->vbio_offset = zio->io_offset;
vbio->vbio_bio = NULL;
vbio->vbio_flags = flags;
return (vbio); return (vbio);
} }
BIO_END_IO_PROTO(vbio_completion, bio, error);
static int static int
vbio_add_page(vbio_t *vbio, struct page *page, uint_t size, uint_t offset) vbio_add_page(vbio_t *vbio, struct page *page, uint_t size, uint_t offset)
{ {
struct bio *bio; struct bio *bio = vbio->vbio_bio;
uint_t ssize; uint_t ssize;
while (size > 0) { while (size > 0) {
bio = vbio->vbio_bio;
if (bio == NULL) { if (bio == NULL) {
/* New BIO, allocate and set up */ /* New BIO, allocate and set up */
bio = vdev_bio_alloc(vbio->vbio_bdev, GFP_NOIO, bio = vdev_bio_alloc(vbio->vbio_bdev, GFP_NOIO,
vbio->vbio_max_segs); vbio->vbio_max_segs);
if (unlikely(bio == NULL)) VERIFY(bio);
return (SET_ERROR(ENOMEM));
BIO_BI_SECTOR(bio) = vbio->vbio_offset >> 9;
bio->bi_next = vbio->vbio_bios; BIO_BI_SECTOR(bio) = vbio->vbio_offset >> 9;
vbio->vbio_bios = vbio->vbio_bio = bio; bio_set_op_attrs(bio,
vbio->vbio_zio->io_type == ZIO_TYPE_WRITE ?
WRITE : READ, vbio->vbio_flags);
if (vbio->vbio_bio) {
bio_chain(vbio->vbio_bio, bio);
vdev_submit_bio(vbio->vbio_bio);
}
vbio->vbio_bio = bio;
} }
/* /*
@ -735,157 +740,97 @@ vbio_add_page(vbio_t *vbio, struct page *page, uint_t size, uint_t offset)
vbio->vbio_offset += BIO_BI_SIZE(bio); vbio->vbio_offset += BIO_BI_SIZE(bio);
/* Signal new BIO allocation wanted */ /* Signal new BIO allocation wanted */
vbio->vbio_bio = NULL; bio = NULL;
} }
return (0); return (0);
} }
BIO_END_IO_PROTO(vdev_disk_io_rw_completion, bio, error); /* Iterator callback to submit ABD pages to the vbio. */
static void vbio_put(vbio_t *vbio); static int
vbio_fill_cb(struct page *page, size_t off, size_t len, void *priv)
static void
vbio_submit(vbio_t *vbio, int flags)
{ {
ASSERT(vbio->vbio_bios); vbio_t *vbio = priv;
struct bio *bio = vbio->vbio_bios; return (vbio_add_page(vbio, page, len, off));
vbio->vbio_bio = vbio->vbio_bios = NULL;
/*
* We take a reference for each BIO as we submit it, plus one to
* protect us from BIOs completing before we're done submitting them
* all, causing vbio_put() to free vbio out from under us and/or the
* zio to be returned before all its IO has completed.
*/
atomic_set(&vbio->vbio_ref, 1);
/*
* If we're submitting more than one BIO, inform the block layer so
* it can batch them if it wants.
*/
struct blk_plug plug;
boolean_t do_plug = (bio->bi_next != NULL);
if (do_plug)
blk_start_plug(&plug);
/* Submit all the BIOs */
while (bio != NULL) {
atomic_inc(&vbio->vbio_ref);
struct bio *next = bio->bi_next;
bio->bi_next = NULL;
bio->bi_end_io = vdev_disk_io_rw_completion;
bio->bi_private = vbio;
bio_set_op_attrs(bio,
vbio->vbio_zio->io_type == ZIO_TYPE_WRITE ?
WRITE : READ, flags);
vdev_submit_bio(bio);
bio = next;
}
/* Finish the batch */
if (do_plug)
blk_finish_plug(&plug);
/* Release the extra reference */
vbio_put(vbio);
} }
/* Create some BIOs, fill them with data and submit them */
static void static void
vbio_return_abd(vbio_t *vbio) vbio_submit(vbio_t *vbio, abd_t *abd, uint64_t size)
{ {
ASSERT(vbio->vbio_bdev);
/*
* We plug so we can submit the BIOs as we go and only unplug them when
* they are fully created and submitted. This is important; if we don't
* plug, then the kernel may start executing earlier BIOs while we're
* still creating and executing later ones, and if the device goes
* away while that's happening, older kernels can get confused and
* trample memory.
*/
struct blk_plug plug;
blk_start_plug(&plug);
(void) abd_iterate_page_func(abd, 0, size, vbio_fill_cb, vbio);
ASSERT(vbio->vbio_bio);
vbio->vbio_bio->bi_end_io = vbio_completion;
vbio->vbio_bio->bi_private = vbio;
vdev_submit_bio(vbio->vbio_bio);
blk_finish_plug(&plug);
vbio->vbio_bio = NULL;
vbio->vbio_bdev = NULL;
}
/* IO completion callback */
BIO_END_IO_PROTO(vbio_completion, bio, error)
{
vbio_t *vbio = bio->bi_private;
zio_t *zio = vbio->vbio_zio; zio_t *zio = vbio->vbio_zio;
if (vbio->vbio_abd == NULL)
return; ASSERT(zio);
/* Capture and log any errors */
#ifdef HAVE_1ARG_BIO_END_IO_T
zio->io_error = BIO_END_IO_ERROR(bio);
#else
zio->io_error = 0;
if (error)
zio->io_error = -(error);
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
zio->io_error = EIO;
#endif
ASSERT3U(zio->io_error, >=, 0);
if (zio->io_error)
vdev_disk_error(zio);
/* Return the BIO to the kernel */
bio_put(bio);
/* /*
* If we copied the ABD before issuing it, clean up and return the copy * If we copied the ABD before issuing it, clean up and return the copy
* to the ADB, with changes if appropriate. * to the ADB, with changes if appropriate.
*/ */
void *buf = abd_to_buf(vbio->vbio_abd); if (vbio->vbio_abd != NULL) {
abd_free(vbio->vbio_abd); void *buf = abd_to_buf(vbio->vbio_abd);
vbio->vbio_abd = NULL; abd_free(vbio->vbio_abd);
vbio->vbio_abd = NULL;
if (zio->io_type == ZIO_TYPE_READ) if (zio->io_type == ZIO_TYPE_READ)
abd_return_buf_copy(zio->io_abd, buf, zio->io_size); abd_return_buf_copy(zio->io_abd, buf, zio->io_size);
else else
abd_return_buf(zio->io_abd, buf, zio->io_size); abd_return_buf(zio->io_abd, buf, zio->io_size);
} }
static void
vbio_free(vbio_t *vbio)
{
VERIFY0(atomic_read(&vbio->vbio_ref));
vbio_return_abd(vbio);
/* Final cleanup */
kmem_free(vbio, sizeof (vbio_t)); kmem_free(vbio, sizeof (vbio_t));
}
static void
vbio_put(vbio_t *vbio)
{
if (atomic_dec_return(&vbio->vbio_ref) > 0)
return;
/*
* This was the last reference, so the entire IO is completed. Clean
* up and submit it for processing.
*/
/*
* Get any data buf back to the original ABD, if necessary. We do this
* now so we can get the ZIO into the pipeline as quickly as possible,
* and then do the remaining cleanup after.
*/
vbio_return_abd(vbio);
zio_t *zio = vbio->vbio_zio;
/*
* Set the overall error. If multiple BIOs returned an error, only the
* first will be taken; the others are dropped (see
* vdev_disk_io_rw_completion()). Its pretty much impossible for
* multiple IOs to the same device to fail with different errors, so
* there's no real risk.
*/
zio->io_error = vbio->vbio_error;
if (zio->io_error)
vdev_disk_error(zio);
/* All done, submit for processing */ /* All done, submit for processing */
zio_delay_interrupt(zio); zio_delay_interrupt(zio);
/* Finish cleanup */
vbio_free(vbio);
}
BIO_END_IO_PROTO(vdev_disk_io_rw_completion, bio, error)
{
vbio_t *vbio = bio->bi_private;
if (vbio->vbio_error == 0) {
#ifdef HAVE_1ARG_BIO_END_IO_T
vbio->vbio_error = BIO_END_IO_ERROR(bio);
#else
if (error)
vbio->vbio_error = -(error);
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
vbio->vbio_error = EIO;
#endif
}
/*
* Destroy the BIO. This is safe to do; the vbio owns its data and the
* kernel won't touch it again after the completion function runs.
*/
bio_put(bio);
/* Drop this BIOs reference acquired by vbio_submit() */
vbio_put(vbio);
} }
/* /*
@ -948,14 +893,6 @@ vdev_disk_check_pages(abd_t *abd, uint64_t size, struct block_device *bdev)
return (B_TRUE); return (B_TRUE);
} }
/* Iterator callback to submit ABD pages to the vbio. */
static int
vdev_disk_fill_vbio_cb(struct page *page, size_t off, size_t len, void *priv)
{
vbio_t *vbio = priv;
return (vbio_add_page(vbio, page, len, off));
}
static int static int
vdev_disk_io_rw(zio_t *zio) vdev_disk_io_rw(zio_t *zio)
{ {
@ -1018,20 +955,12 @@ vdev_disk_io_rw(zio_t *zio)
} }
/* Allocate vbio, with a pointer to the borrowed ABD if necessary */ /* Allocate vbio, with a pointer to the borrowed ABD if necessary */
int error = 0; vbio_t *vbio = vbio_alloc(zio, bdev, flags);
vbio_t *vbio = vbio_alloc(zio, bdev);
if (abd != zio->io_abd) if (abd != zio->io_abd)
vbio->vbio_abd = abd; vbio->vbio_abd = abd;
/* Fill it with pages */ /* Fill it with data pages and submit it to the kernel */
error = abd_iterate_page_func(abd, 0, zio->io_size, vbio_submit(vbio, abd, zio->io_size);
vdev_disk_fill_vbio_cb, vbio);
if (error != 0) {
vbio_free(vbio);
return (error);
}
vbio_submit(vbio, flags);
return (0); return (0);
} }