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dm mpath: changes from initial m->flags locking audit

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Fix locking in slow-paths where m->lock should be taken.

Signed-off-by: Mike Snitzer <snitzer@rredhat.com>
This commit is contained in:
Mike Snitzer 2020-06-10 15:02:37 -04:00
parent 11ba468877
commit 69cea0d45a
1 changed files with 13 additions and 3 deletions
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16
drivers/md/dm-mpath.c
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@ -335,6 +335,8 @@ static int pg_init_all_paths(struct multipath *m)
static void __switch_pg(struct multipath *m, struct priority_group *pg)
{
lockdep_assert_held(&m->lock);
m->current_pg = pg;
/* Must we initialise the PG first, and queue I/O till it's ready? */
@ -382,7 +384,9 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
unsigned bypassed = 1;
if (!atomic_read(&m->nr_valid_paths)) {
spin_lock_irqsave(&m->lock, flags);
clear_bit(MPATHF_QUEUE_IO, &m->flags);
spin_unlock_irqrestore(&m->lock, flags);
goto failed;
}
@ -422,8 +426,11 @@ check_current_pg:
continue;
pgpath = choose_path_in_pg(m, pg, nr_bytes);
if (!IS_ERR_OR_NULL(pgpath)) {
if (!bypassed)
if (!bypassed) {
spin_lock_irqsave(&m->lock, flags);
set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
spin_unlock_irqrestore(&m->lock, flags);
}
return pgpath;
}
}
@ -1662,9 +1669,9 @@ static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone,
spin_lock_irqsave(&m->lock, flags);
bio_list_add(&m->queued_bios, clone);
spin_unlock_irqrestore(&m->lock, flags);
if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
queue_work(kmultipathd, &m->process_queued_bios);
spin_unlock_irqrestore(&m->lock, flags);
r = DM_ENDIO_INCOMPLETE;
done:
@ -1938,6 +1945,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
{
struct multipath *m = ti->private;
struct pgpath *current_pgpath;
unsigned long flags;
int r;
current_pgpath = READ_ONCE(m->current_pgpath);
@ -1965,8 +1973,10 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
/* Path status changed, redo selection */
(void) choose_pgpath(m, 0);
}
spin_lock_irqsave(&m->lock, flags);
if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
pg_init_all_paths(m);
(void) __pg_init_all_paths(m);
spin_unlock_irqrestore(&m->lock, flags);
dm_table_run_md_queue_async(m->ti->table);
process_queued_io_list(m);
}