This is a note to let you know that I've just added the patch titled
dm: remove special-casing of bio-based immutable singleton target on NVMe
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-remove-special-casing-of-bio-based-immutable-singleton-target-on-nvme.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From snitzer@xxxxxxxxxx Thu Jun 23 17:47:22 2022
From: Mike Snitzer <snitzer@xxxxxxxxxx>
Date: Tue, 21 Jun 2022 12:35:04 -0400
Subject: dm: remove special-casing of bio-based immutable singleton target on NVMe
To: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>, Mike Snitzer <snitzer@xxxxxxxxxx>, keescook@xxxxxxxxxxxx, sarthakkukreti@xxxxxxxxxx, stable@xxxxxxxxxxxxxxx, Oleksandr Tymoshenko <ovt@xxxxxxxxxx>, dm-devel@xxxxxxxxxx, regressions@xxxxxxxxxxxxxxx
Message-ID: <YrHzOGO5fOSFwqdJ@xxxxxxxxxx>
Content-Disposition: inline
From: Mike Snitzer <snitzer@xxxxxxxxxx>
Commit 9c37de297f6590937f95a28bec1b7ac68a38618f upstream.
There is no benefit to DM special-casing NVMe. Remove all code used to
establish DM_TYPE_NVME_BIO_BASED.
Also, remove 3 'struct mapped_device *md' variables in __map_bio() which
masked the same variable that is available within __map_bio()'s scope.
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-table.c | 32 +-----------------
drivers/md/dm.c | 73 ++++--------------------------------------
include/linux/device-mapper.h | 1
3 files changed, 9 insertions(+), 97 deletions(-)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -872,8 +872,7 @@ EXPORT_SYMBOL(dm_consume_args);
static bool __table_type_bio_based(enum dm_queue_mode table_type)
{
return (table_type == DM_TYPE_BIO_BASED ||
- table_type == DM_TYPE_DAX_BIO_BASED ||
- table_type == DM_TYPE_NVME_BIO_BASED);
+ table_type == DM_TYPE_DAX_BIO_BASED);
}
static bool __table_type_request_based(enum dm_queue_mode table_type)
@@ -929,8 +928,6 @@ bool dm_table_supports_dax(struct dm_tab
return true;
}
-static bool dm_table_does_not_support_partial_completion(struct dm_table *t);
-
static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
@@ -960,7 +957,6 @@ static int dm_table_determine_type(struc
goto verify_bio_based;
}
BUG_ON(t->type == DM_TYPE_DAX_BIO_BASED);
- BUG_ON(t->type == DM_TYPE_NVME_BIO_BASED);
goto verify_rq_based;
}
@@ -999,15 +995,6 @@ verify_bio_based:
if (dm_table_supports_dax(t, device_not_dax_capable, &page_size) ||
(list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED)) {
t->type = DM_TYPE_DAX_BIO_BASED;
- } else {
- /* Check if upgrading to NVMe bio-based is valid or required */
- tgt = dm_table_get_immutable_target(t);
- if (tgt && !tgt->max_io_len && dm_table_does_not_support_partial_completion(t)) {
- t->type = DM_TYPE_NVME_BIO_BASED;
- goto verify_rq_based; /* must be stacked directly on NVMe (blk-mq) */
- } else if (list_empty(devices) && live_md_type == DM_TYPE_NVME_BIO_BASED) {
- t->type = DM_TYPE_NVME_BIO_BASED;
- }
}
return 0;
}
@@ -1024,8 +1011,7 @@ verify_rq_based:
* (e.g. request completion process for partial completion.)
*/
if (t->num_targets > 1) {
- DMERR("%s DM doesn't support multiple targets",
- t->type == DM_TYPE_NVME_BIO_BASED ? "nvme bio-based" : "request-based");
+ DMERR("request-based DM doesn't support multiple targets");
return -EINVAL;
}
@@ -1714,20 +1700,6 @@ static int device_is_not_random(struct d
return q && !blk_queue_add_random(q);
}
-static int device_is_partial_completion(struct dm_target *ti, struct dm_dev *dev,
- sector_t start, sector_t len, void *data)
-{
- char b[BDEVNAME_SIZE];
-
- /* For now, NVMe devices are the only devices of this class */
- return (strncmp(bdevname(dev->bdev, b), "nvme", 4) != 0);
-}
-
-static bool dm_table_does_not_support_partial_completion(struct dm_table *t)
-{
- return !dm_table_any_dev_attr(t, device_is_partial_completion, NULL);
-}
-
static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1000,7 +1000,7 @@ static void clone_endio(struct bio *bio)
struct mapped_device *md = tio->io->md;
dm_endio_fn endio = tio->ti->type->end_io;
- if (unlikely(error == BLK_STS_TARGET) && md->type != DM_TYPE_NVME_BIO_BASED) {
+ if (unlikely(error == BLK_STS_TARGET)) {
if (bio_op(bio) == REQ_OP_DISCARD &&
!bio->bi_disk->queue->limits.max_discard_sectors)
disable_discard(md);
@@ -1325,7 +1325,6 @@ static blk_qc_t __map_bio(struct dm_targ
sector = clone->bi_iter.bi_sector;
if (unlikely(swap_bios_limit(ti, clone))) {
- struct mapped_device *md = io->md;
int latch = get_swap_bios();
if (unlikely(latch != md->swap_bios))
__set_swap_bios_limit(md, latch);
@@ -1340,24 +1339,17 @@ static blk_qc_t __map_bio(struct dm_targ
/* the bio has been remapped so dispatch it */
trace_block_bio_remap(clone->bi_disk->queue, clone,
bio_dev(io->orig_bio), sector);
- if (md->type == DM_TYPE_NVME_BIO_BASED)
- ret = direct_make_request(clone);
- else
- ret = generic_make_request(clone);
+ ret = generic_make_request(clone);
break;
case DM_MAPIO_KILL:
- if (unlikely(swap_bios_limit(ti, clone))) {
- struct mapped_device *md = io->md;
+ if (unlikely(swap_bios_limit(ti, clone)))
up(&md->swap_bios_semaphore);
- }
free_tio(tio);
dec_pending(io, BLK_STS_IOERR);
break;
case DM_MAPIO_REQUEUE:
- if (unlikely(swap_bios_limit(ti, clone))) {
- struct mapped_device *md = io->md;
+ if (unlikely(swap_bios_limit(ti, clone)))
up(&md->swap_bios_semaphore);
- }
free_tio(tio);
dec_pending(io, BLK_STS_DM_REQUEUE);
break;
@@ -1732,51 +1724,6 @@ static blk_qc_t __split_and_process_bio(
return ret;
}
-/*
- * Optimized variant of __split_and_process_bio that leverages the
- * fact that targets that use it do _not_ have a need to split bios.
- */
-static blk_qc_t __process_bio(struct mapped_device *md, struct dm_table *map,
- struct bio *bio, struct dm_target *ti)
-{
- struct clone_info ci;
- blk_qc_t ret = BLK_QC_T_NONE;
- int error = 0;
-
- init_clone_info(&ci, md, map, bio);
-
- if (bio->bi_opf & REQ_PREFLUSH) {
- struct bio flush_bio;
-
- /*
- * Use an on-stack bio for this, it's safe since we don't
- * need to reference it after submit. It's just used as
- * the basis for the clone(s).
- */
- bio_init(&flush_bio, NULL, 0);
- flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
- ci.bio = &flush_bio;
- ci.sector_count = 0;
- error = __send_empty_flush(&ci);
- bio_uninit(ci.bio);
- /* dec_pending submits any data associated with flush */
- } else {
- struct dm_target_io *tio;
-
- ci.bio = bio;
- ci.sector_count = bio_sectors(bio);
- if (__process_abnormal_io(&ci, ti, &error))
- goto out;
-
- tio = alloc_tio(&ci, ti, 0, GFP_NOIO);
- ret = __clone_and_map_simple_bio(&ci, tio, NULL);
- }
-out:
- /* drop the extra reference count */
- dec_pending(ci.io, errno_to_blk_status(error));
- return ret;
-}
-
static blk_qc_t dm_process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
@@ -1807,8 +1754,6 @@ static blk_qc_t dm_process_bio(struct ma
/* regular IO is split by __split_and_process_bio */
}
- if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
- return __process_bio(md, map, bio, ti);
return __split_and_process_bio(md, map, bio);
}
@@ -2200,12 +2145,10 @@ static struct dm_table *__bind(struct ma
if (request_based)
dm_stop_queue(q);
- if (request_based || md->type == DM_TYPE_NVME_BIO_BASED) {
+ if (request_based) {
/*
- * Leverage the fact that request-based DM targets and
- * NVMe bio based targets are immutable singletons
- * - used to optimize both dm_request_fn and dm_mq_queue_rq;
- * and __process_bio.
+ * Leverage the fact that request-based DM targets are
+ * immutable singletons - used to optimize dm_mq_queue_rq.
*/
md->immutable_target = dm_table_get_immutable_target(t);
}
@@ -2334,7 +2277,6 @@ int dm_setup_md_queue(struct mapped_devi
break;
case DM_TYPE_BIO_BASED:
case DM_TYPE_DAX_BIO_BASED:
- case DM_TYPE_NVME_BIO_BASED:
dm_init_congested_fn(md);
break;
case DM_TYPE_NONE:
@@ -3070,7 +3012,6 @@ struct dm_md_mempools *dm_alloc_md_mempo
switch (type) {
case DM_TYPE_BIO_BASED:
case DM_TYPE_DAX_BIO_BASED:
- case DM_TYPE_NVME_BIO_BASED:
pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);
front_pad = roundup(per_io_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
io_front_pad = roundup(front_pad, __alignof__(struct dm_io)) + offsetof(struct dm_io, tio);
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -28,7 +28,6 @@ enum dm_queue_mode {
DM_TYPE_BIO_BASED = 1,
DM_TYPE_REQUEST_BASED = 2,
DM_TYPE_DAX_BIO_BASED = 3,
- DM_TYPE_NVME_BIO_BASED = 4,
};
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
Patches currently in stable-queue which might be from snitzer@xxxxxxxxxx are
queue-5.4/dm-remove-special-casing-of-bio-based-immutable-singleton-target-on-nvme.patch
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