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vdev_disk: rename existing functions to vdev_classic_*
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This is just renaming the existing functions we're about to replace and
grouping them together to make the next commits easier to follow.

Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Rob Norris <[email protected]>
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Closes #15533
Closes #15588
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@robn @behlendorf
robn authored and behlendorf committed Mar 25, 2024
1 parent 390b448 commit f3b85d7
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Showing 3 changed files with 120 additions and 102 deletions.
2 changes: 2 additions & 0 deletions include/sys/abd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -220,6 +220,8 @@ void abd_fini(void);

/*
* Linux ABD bio functions
* Note: these are only needed to support vdev_classic. See comment in
* vdev_disk.c.
*/
#if defined(__linux__) && defined(_KERNEL)
unsigned int abd_bio_map_off(struct bio *, abd_t *, unsigned int, size_t);
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5 changes: 5 additions & 0 deletions module/os/linux/zfs/abd_os.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1096,6 +1096,11 @@ abd_iter_page(struct abd_iter *aiter)
aiter->iter_page_dsize = MIN(dsize, page_size(page) - doff);
}

/*
* Note: ABD BIO functions only needed to support vdev_classic. See comments in
* vdev_disk.c.
*/

/*
* bio_nr_pages for ABD.
* @off is the offset in @abd
Expand Down
215 changes: 113 additions & 102 deletions module/os/linux/zfs/vdev_disk.c
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Original file line number Diff line number Diff line change
Expand Up @@ -83,17 +83,6 @@ static uint_t zfs_vdev_open_timeout_ms = 1000;
*/
#define EFI_MIN_RESV_SIZE (16 * 1024)

/*
* Virtual device vector for disks.
*/
typedef struct dio_request {
zio_t *dr_zio; /* Parent ZIO */
atomic_t dr_ref; /* References */
int dr_error; /* Bio error */
int dr_bio_count; /* Count of bio's */
struct bio *dr_bio[]; /* Attached bio's */
} dio_request_t;

/*
* BIO request failfast mask.
*/
Expand Down Expand Up @@ -467,85 +456,6 @@ vdev_disk_close(vdev_t *v)
v->vdev_tsd = NULL;
}

static dio_request_t *
vdev_disk_dio_alloc(int bio_count)
{
dio_request_t *dr = kmem_zalloc(sizeof (dio_request_t) +
sizeof (struct bio *) * bio_count, KM_SLEEP);
atomic_set(&dr->dr_ref, 0);
dr->dr_bio_count = bio_count;
dr->dr_error = 0;

for (int i = 0; i < dr->dr_bio_count; i++)
dr->dr_bio[i] = NULL;

return (dr);
}

static void
vdev_disk_dio_free(dio_request_t *dr)
{
int i;

for (i = 0; i < dr->dr_bio_count; i++)
if (dr->dr_bio[i])
bio_put(dr->dr_bio[i]);

kmem_free(dr, sizeof (dio_request_t) +
sizeof (struct bio *) * dr->dr_bio_count);
}

static void
vdev_disk_dio_get(dio_request_t *dr)
{
atomic_inc(&dr->dr_ref);
}

static void
vdev_disk_dio_put(dio_request_t *dr)
{
int rc = atomic_dec_return(&dr->dr_ref);

/*
* Free the dio_request when the last reference is dropped and
* ensure zio_interpret is called only once with the correct zio
*/
if (rc == 0) {
zio_t *zio = dr->dr_zio;
int error = dr->dr_error;

vdev_disk_dio_free(dr);

if (zio) {
zio->io_error = error;
ASSERT3S(zio->io_error, >=, 0);
if (zio->io_error)
vdev_disk_error(zio);

zio_delay_interrupt(zio);
}
}
}

BIO_END_IO_PROTO(vdev_disk_physio_completion, bio, error)
{
dio_request_t *dr = bio->bi_private;

if (dr->dr_error == 0) {
#ifdef HAVE_1ARG_BIO_END_IO_T
dr->dr_error = BIO_END_IO_ERROR(bio);
#else
if (error)
dr->dr_error = -(error);
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
dr->dr_error = EIO;
#endif
}

/* Drop reference acquired by __vdev_disk_physio */
vdev_disk_dio_put(dr);
}

static inline void
vdev_submit_bio_impl(struct bio *bio)
{
Expand Down Expand Up @@ -697,8 +607,107 @@ vdev_bio_alloc(struct block_device *bdev, gfp_t gfp_mask,
return (bio);
}

/* ========== */

/*
* This is the classic, battle-tested BIO submission code.
*
* These functions have been renamed to vdev_classic_* to make it clear what
* they belong to, but their implementations are unchanged.
*/

/*
* Virtual device vector for disks.
*/
typedef struct dio_request {
zio_t *dr_zio; /* Parent ZIO */
atomic_t dr_ref; /* References */
int dr_error; /* Bio error */
int dr_bio_count; /* Count of bio's */
struct bio *dr_bio[]; /* Attached bio's */
} dio_request_t;

static dio_request_t *
vdev_classic_dio_alloc(int bio_count)
{
dio_request_t *dr = kmem_zalloc(sizeof (dio_request_t) +
sizeof (struct bio *) * bio_count, KM_SLEEP);
atomic_set(&dr->dr_ref, 0);
dr->dr_bio_count = bio_count;
dr->dr_error = 0;

for (int i = 0; i < dr->dr_bio_count; i++)
dr->dr_bio[i] = NULL;

return (dr);
}

static void
vdev_classic_dio_free(dio_request_t *dr)
{
int i;

for (i = 0; i < dr->dr_bio_count; i++)
if (dr->dr_bio[i])
bio_put(dr->dr_bio[i]);

kmem_free(dr, sizeof (dio_request_t) +
sizeof (struct bio *) * dr->dr_bio_count);
}

static void
vdev_classic_dio_get(dio_request_t *dr)
{
atomic_inc(&dr->dr_ref);
}

static void
vdev_classic_dio_put(dio_request_t *dr)
{
int rc = atomic_dec_return(&dr->dr_ref);

/*
* Free the dio_request when the last reference is dropped and
* ensure zio_interpret is called only once with the correct zio
*/
if (rc == 0) {
zio_t *zio = dr->dr_zio;
int error = dr->dr_error;

vdev_classic_dio_free(dr);

if (zio) {
zio->io_error = error;
ASSERT3S(zio->io_error, >=, 0);
if (zio->io_error)
vdev_disk_error(zio);

zio_delay_interrupt(zio);
}
}
}

BIO_END_IO_PROTO(vdev_classic_physio_completion, bio, error)
{
dio_request_t *dr = bio->bi_private;

if (dr->dr_error == 0) {
#ifdef HAVE_1ARG_BIO_END_IO_T
dr->dr_error = BIO_END_IO_ERROR(bio);
#else
if (error)
dr->dr_error = -(error);
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
dr->dr_error = EIO;
#endif
}

/* Drop reference acquired by vdev_classic_physio */
vdev_classic_dio_put(dr);
}

static inline unsigned int
vdev_bio_max_segs(zio_t *zio, int bio_size, uint64_t abd_offset)
vdev_classic_bio_max_segs(zio_t *zio, int bio_size, uint64_t abd_offset)
{
unsigned long nr_segs = abd_nr_pages_off(zio->io_abd,
bio_size, abd_offset);
Expand All @@ -711,7 +720,7 @@ vdev_bio_max_segs(zio_t *zio, int bio_size, uint64_t abd_offset)
}

static int
__vdev_disk_physio(struct block_device *bdev, zio_t *zio,
vdev_classic_physio(struct block_device *bdev, zio_t *zio,
size_t io_size, uint64_t io_offset, int rw, int flags)
{
dio_request_t *dr;
Expand All @@ -736,7 +745,7 @@ __vdev_disk_physio(struct block_device *bdev, zio_t *zio,
}

retry:
dr = vdev_disk_dio_alloc(bio_count);
dr = vdev_classic_dio_alloc(bio_count);

if (!(zio->io_flags & (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)) &&
zio->io_vd->vdev_failfast == B_TRUE) {
Expand Down Expand Up @@ -771,23 +780,23 @@ __vdev_disk_physio(struct block_device *bdev, zio_t *zio,
* this should be rare - see the comment above.
*/
if (dr->dr_bio_count == i) {
vdev_disk_dio_free(dr);
vdev_classic_dio_free(dr);
bio_count *= 2;
goto retry;
}

nr_vecs = vdev_bio_max_segs(zio, bio_size, abd_offset);
nr_vecs = vdev_classic_bio_max_segs(zio, bio_size, abd_offset);
dr->dr_bio[i] = vdev_bio_alloc(bdev, GFP_NOIO, nr_vecs);
if (unlikely(dr->dr_bio[i] == NULL)) {
vdev_disk_dio_free(dr);
vdev_classic_dio_free(dr);
return (SET_ERROR(ENOMEM));
}

/* Matching put called by vdev_disk_physio_completion */
vdev_disk_dio_get(dr);
/* Matching put called by vdev_classic_physio_completion */
vdev_classic_dio_get(dr);

BIO_BI_SECTOR(dr->dr_bio[i]) = bio_offset >> 9;
dr->dr_bio[i]->bi_end_io = vdev_disk_physio_completion;
dr->dr_bio[i]->bi_end_io = vdev_classic_physio_completion;
dr->dr_bio[i]->bi_private = dr;
bio_set_op_attrs(dr->dr_bio[i], rw, flags);

Expand All @@ -801,7 +810,7 @@ __vdev_disk_physio(struct block_device *bdev, zio_t *zio,
}

/* Extra reference to protect dio_request during vdev_submit_bio */
vdev_disk_dio_get(dr);
vdev_classic_dio_get(dr);

if (dr->dr_bio_count > 1)
blk_start_plug(&plug);
Expand All @@ -815,11 +824,13 @@ __vdev_disk_physio(struct block_device *bdev, zio_t *zio,
if (dr->dr_bio_count > 1)
blk_finish_plug(&plug);

vdev_disk_dio_put(dr);
vdev_classic_dio_put(dr);

return (error);
}

/* ========== */

BIO_END_IO_PROTO(vdev_disk_io_flush_completion, bio, error)
{
zio_t *zio = bio->bi_private;
Expand Down Expand Up @@ -1023,7 +1034,7 @@ vdev_disk_io_start(zio_t *zio)
}

zio->io_target_timestamp = zio_handle_io_delay(zio);
error = __vdev_disk_physio(BDH_BDEV(vd->vd_bdh), zio,
error = vdev_classic_physio(BDH_BDEV(vd->vd_bdh), zio,
zio->io_size, zio->io_offset, rw, 0);
rw_exit(&vd->vd_lock);

Expand Down

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