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dm: simplify dm_sumbit_bio_remap interface

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Remove the from_wq argument from dm_sumbit_bio_remap(). Eliminates the
need for dm_sumbit_bio_remap() callers to know whether they are
calling for a workqueue or from the original dm_submit_bio().

Add map_task to dm_io struct, record the map_task in alloc_io and
clear it after all target ->map() calls have completed. Update
dm_sumbit_bio_remap to check if 'current' matches io->map_task rather
than rely on passed 'from_rq' argument.

This change really simplifies the chore of porting each DM target to
using dm_sumbit_bio_remap() because there is no longer the risk of
programming error by not completely knowing all the different contexts
a particular method that calls dm_sumbit_bio_remap() might be used in.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2022-03-10 11:45:58 -05:00
parent a92512819b
commit b7f8dff098
6 changed files with 12 additions and 11 deletions
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1
drivers/md/dm-core.h
View File

@ -237,6 +237,7 @@ struct dm_io {
unsigned long start_time;
void *data;
struct hlist_node node;
struct task_struct *map_task;
spinlock_t endio_lock;
struct dm_stats_aux stats_aux;
/* last member of dm_target_io is 'struct bio' */

6
drivers/md/dm-crypt.c
View File

@ -1857,7 +1857,7 @@ static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
return 1;
}
dm_submit_bio_remap(io->base_bio, clone, (gfp != CRYPT_MAP_READ_GFP));
dm_submit_bio_remap(io->base_bio, clone);
return 0;
}
@ -1883,7 +1883,7 @@ static void kcryptd_io_write(struct dm_crypt_io *io)
{
struct bio *clone = io->ctx.bio_out;
dm_submit_bio_remap(io->base_bio, clone, true);
dm_submit_bio_remap(io->base_bio, clone);
}
#define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node)
@ -1962,7 +1962,7 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
if ((likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) ||
test_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags)) {
dm_submit_bio_remap(io->base_bio, clone, true);
dm_submit_bio_remap(io->base_bio, clone);
return;
}

2
drivers/md/dm-delay.c
View File

@ -72,7 +72,7 @@ static void flush_bios(struct bio *bio)
while (bio) {
n = bio->bi_next;
bio->bi_next = NULL;
dm_submit_bio_remap(bio, NULL, true);
dm_submit_bio_remap(bio, NULL);
bio = n;
}
}

4
drivers/md/dm-thin.c
View File

@ -755,7 +755,7 @@ static void issue(struct thin_c *tc, struct bio *bio)
struct pool *pool = tc->pool;
if (!bio_triggers_commit(tc, bio)) {
dm_submit_bio_remap(bio, NULL, true);
dm_submit_bio_remap(bio, NULL);
return;
}
@ -2383,7 +2383,7 @@ static void process_deferred_bios(struct pool *pool)
if (bio->bi_opf & REQ_PREFLUSH)
bio_endio(bio);
else
dm_submit_bio_remap(bio, NULL, true);
dm_submit_bio_remap(bio, NULL);
}
}

8
drivers/md/dm.c
View File

@ -574,6 +574,7 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
this_cpu_inc(*md->pending_io);
io->orig_bio = NULL;
io->md = md;
io->map_task = current;
spin_lock_init(&io->endio_lock);
io->start_time = jiffies;
@ -1189,15 +1190,13 @@ static inline void __dm_submit_bio_remap(struct bio *clone,
/*
* @clone: clone bio that DM core passed to target's .map function
* @tgt_clone: clone of @clone bio that target needs submitted
* @from_wq: caller is a workqueue thread managed by DM target
*
* Targets should use this interface to submit bios they take
* ownership of when returning DM_MAPIO_SUBMITTED.
*
* Target should also enable ti->accounts_remapped_io
*/
void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone,
bool from_wq)
void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
{
struct dm_target_io *tio = clone_to_tio(clone);
struct dm_io *io = tio->io;
@ -1212,7 +1211,7 @@ void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone,
* Account io->origin_bio to DM dev on behalf of target
* that took ownership of IO with DM_MAPIO_SUBMITTED.
*/
if (!from_wq) {
if (io->map_task == current) {
/* Still in target's map function */
io->start_io_acct = true;
} else {
@ -1568,6 +1567,7 @@ static void dm_split_and_process_bio(struct mapped_device *md,
}
error = __split_and_process_bio(&ci);
ci.io->map_task = NULL;
if (error || !ci.sector_count)
goto out;

2
include/linux/device-mapper.h
View File

@ -471,7 +471,7 @@ int dm_suspended(struct dm_target *ti);
int dm_post_suspending(struct dm_target *ti);
int dm_noflush_suspending(struct dm_target *ti);
void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone, bool from_wq);
void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone);
union map_info *dm_get_rq_mapinfo(struct request *rq);
#ifdef CONFIG_BLK_DEV_ZONED