[PATCH] mmc: Fix tag set memory leak

From: Raul E Rangel
Date: Thu May 02 2019 - 15:07:47 EST

The tag set is allocated in mmc_init_queue but never freed. This results
in a memory leak. This change makes sure we free the tag set when the
queue is also freed.

Signed-off-by: Raul E Rangel <rrangel@xxxxxxxxxxxx>
I found this using kmemleak and plugging and unplugging an SD card in a
few times.

Here is an example of the output of kmemleak:
unreferenced object 0xffff888125be4ce8 (size 8):
comm "kworker/1:0", pid 17, jiffies 4294901575 (age 204.773s)
hex dump (first 8 bytes):
00 00 00 00 00 00 00 00 ........
[<0000000061cb8887>] blk_mq_alloc_tag_set+0xe9/0x234
[<00000000cf532a0f>] mmc_init_queue+0xa9/0x2f0
[<000000001e085171>] mmc_blk_alloc_req+0x125/0x2f9
[<00000000eae1bd01>] mmc_blk_probe+0x1e2/0x6c1
[<00000000a0b4a87d>] really_probe+0x1bd/0x3b0
[<00000000e58f3eb9>] driver_probe_device+0xe1/0x115
[<00000000358f3b3c>] bus_for_each_drv+0x89/0xac
[<00000000ef52ccbe>] __device_attach+0xb0/0x14a
[<00000000c9daafa7>] bus_probe_device+0x33/0x9f
[<0000000008ac5779>] device_add+0x34b/0x5e2
[<00000000b42623cc>] mmc_add_card+0x1f5/0x20d
[<00000000f114ebc3>] mmc_attach_sd+0xc5/0x14b
[<000000006e915e0d>] mmc_rescan+0x261/0x2b6
[<00000000e5b49c26>] process_one_work+0x1d3/0x31f
[<0000000068c8cd3c>] worker_thread+0x1cd/0x2bf
[<00000000326e2e22>] kthread+0x14f/0x157

Once I applied this patch the leak went away.

p.s., I included a small white space fix. Hope that's ok.

drivers/mmc/core/queue.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 7c364a9c4eeb..176a08748cf1 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -402,7 +402,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card)

mq->card = card;
mq->use_cqe = host->cqe_enabled;

memset(&mq->tag_set, 0, sizeof(mq->tag_set));
@@ -472,6 +472,7 @@ void mmc_cleanup_queue(struct mmc_queue *mq)

+ blk_mq_free_tag_set(&mq->tag_set);

* A request can be completed before the next request, potentially