From 69cea0d45a618ad4ae74f36386ef1af5128b2b19 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Wed, 10 Jun 2020 15:02:37 -0400
Subject: [PATCH] dm mpath: changes from initial m->flags locking audit
Git-commit: 69cea0d45a618ad4ae74f36386ef1af5128b2b19
Patch-mainline: v5.9-rc1
References: bsc#1175995, jsc#SLE-15608
Fix locking in slow-paths where m->lock should be taken.
Signed-off-by: Mike Snitzer <snitzer@rredhat.com>
Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/dm-mpath.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 78cff42d987e..d7bb74bded8c 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -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 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
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);
}
--
2.26.2