In mmc_queue_setup_discard() the mmc driver queue's discard_granularity
might be set as 0 (when card->pref_erase > max_discard) while the mmc
device still declares to support discard operation. This is buggy and
triggered the following kernel warning message,
WARNING: CPU: 0 PID: 135 at __blkdev_issue_discard+0x200/0x294
CPU: 0 PID: 135 Comm: f2fs_discard-17 Not tainted 5.9.0-rc6 #1
Hardware name: Google Kevin (DT)
pstate: 00000005 (nzcv daif -PAN -UAO BTYPE=--)
pc : __blkdev_issue_discard+0x200/0x294
lr : __blkdev_issue_discard+0x54/0x294
sp : ffff800011dd3b10
x29: ffff800011dd3b10 x28: 0000000000000000 x27: ffff800011dd3cc4 x26: ffff800011dd3e18 x25: 000000000004e69b x24: 0000000000000c40 x23: ffff0000f1deaaf0 x22: ffff0000f2849200 x21: 00000000002734d8 x20: 0000000000000008 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000394 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 00000000000008b0 x9 : ffff800011dd3cb0 x8 : 000000000004e69b x7 : 0000000000000000 x6 : ffff0000f1926400 x5 : ffff0000f1940800 x4 : 0000000000000000 x3 : 0000000000000c40 x2 : 0000000000000008 x1 : 00000000002734d8 x0 : 0000000000000000 Call trace:
__blkdev_issue_discard+0x200/0x294
__submit_discard_cmd+0x128/0x374
__issue_discard_cmd_orderly+0x188/0x244
__issue_discard_cmd+0x2e8/0x33c
issue_discard_thread+0xe8/0x2f0
kthread+0x11c/0x120
ret_from_fork+0x10/0x1c
---[ end trace e4c8023d33dfe77a ]---
This patch fixes the issue by setting discard_granularity as SECTOR_SIZE
instead of 0 when (card->pref_erase > max_discard) is true. Now no more
complain from __blkdev_issue_discard() for the improper value of discard
granularity.
This issue is exposed after commit b35fd7422c2f ("block: check queue's
limits.discard_granularity in __blkdev_issue_discard()"), a "Fixes:" tag
is also added for the commit to make sure people won't miss this patch
after applying the change of __blkdev_issue_discard().
Fixes: e056a1b5b67b ("mmc: queue: let host controllers specify maximum discard timeout")
Fixes: b35fd7422c2f ("block: check queue's limits.discard_granularity in __blkdev_issue_discard()").
Reported-and-tested-by: Vicente Bergas <[email protected]>
Signed-off-by: Coly Li <[email protected]>
Acked-by: Adrian Hunter <[email protected]>
Cc: Ulf Hansson <[email protected]>
---
Changelog,
v4, update to Reported-and-tested-by tag for Vicente Bergas.
v3, add Fixes tag for both commits.
v2, change commit id of the Fixes tag.
v1, initial version.
drivers/mmc/core/queue.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 6c022ef0f84d..350d0cc4ee62 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -190,7 +190,7 @@ static void mmc_queue_setup_discard(struct request_queue *q,
q->limits.discard_granularity = card->pref_erase << 9;
/* granularity must not be greater than max. discard */
if (card->pref_erase > max_discard)
- q->limits.discard_granularity = 0;
+ q->limits.discard_granularity = SECTOR_SIZE;
if (mmc_can_secure_erase_trim(card))
blk_queue_flag_set(QUEUE_FLAG_SECERASE, q);
}
--
2.26.2
Coly,
> diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
> index 6c022ef0f84d..350d0cc4ee62 100644
> --- a/drivers/mmc/core/queue.c
> +++ b/drivers/mmc/core/queue.c
> @@ -190,7 +190,7 @@ static void mmc_queue_setup_discard(struct request_queue *q,
> q->limits.discard_granularity = card->pref_erase << 9;
> /* granularity must not be greater than max. discard */
> if (card->pref_erase > max_discard)
> - q->limits.discard_granularity = 0;
> + q->limits.discard_granularity = SECTOR_SIZE;
> if (mmc_can_secure_erase_trim(card))
> blk_queue_flag_set(QUEUE_FLAG_SECERASE, q);
> }
The granularity should probably be set to the logical block size instead
of SECTOR_SIZE. However, looking at mmc_setup_queue() it doesn't appear
the logical block size is read from the CSD until after discard has been
configured. So that will require a bit of code shuffling.
--
Martin K. Petersen Oracle Linux Engineering
On 2020/10/2 20:57, Martin K. Petersen wrote:
>
> Coly,
>
>> diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
>> index 6c022ef0f84d..350d0cc4ee62 100644
>> --- a/drivers/mmc/core/queue.c
>> +++ b/drivers/mmc/core/queue.c
>> @@ -190,7 +190,7 @@ static void mmc_queue_setup_discard(struct request_queue *q,
>> q->limits.discard_granularity = card->pref_erase << 9;
>> /* granularity must not be greater than max. discard */
>> if (card->pref_erase > max_discard)
>> - q->limits.discard_granularity = 0;
>> + q->limits.discard_granularity = SECTOR_SIZE;
>> if (mmc_can_secure_erase_trim(card))
>> blk_queue_flag_set(QUEUE_FLAG_SECERASE, q);
>> }
>
Hi Martin,
> The granularity should probably be set to the logical block size instead
> of SECTOR_SIZE. However, looking at mmc_setup_queue() it doesn't appear
> the logical block size is read from the CSD until after discard has been
> configured. So that will require a bit of code shuffling.
>
Copied, then let me try to modify mmc_setup_queue() too, and set the
discard_granularity from SECTOR_SIZE to logical block size.
Thanks for the hint.
Coly Li
On Fri, 2 Oct 2020 at 03:39, Coly Li <[email protected]> wrote:
>
> In mmc_queue_setup_discard() the mmc driver queue's discard_granularity
> might be set as 0 (when card->pref_erase > max_discard) while the mmc
> device still declares to support discard operation. This is buggy and
> triggered the following kernel warning message,
>
> WARNING: CPU: 0 PID: 135 at __blkdev_issue_discard+0x200/0x294
> CPU: 0 PID: 135 Comm: f2fs_discard-17 Not tainted 5.9.0-rc6 #1
> Hardware name: Google Kevin (DT)
> pstate: 00000005 (nzcv daif -PAN -UAO BTYPE=--)
> pc : __blkdev_issue_discard+0x200/0x294
> lr : __blkdev_issue_discard+0x54/0x294
> sp : ffff800011dd3b10
> x29: ffff800011dd3b10 x28: 0000000000000000 x27: ffff800011dd3cc4 x26: ffff800011dd3e18 x25: 000000000004e69b x24: 0000000000000c40 x23: ffff0000f1deaaf0 x22: ffff0000f2849200 x21: 00000000002734d8 x20: 0000000000000008 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000394 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 00000000000008b0 x9 : ffff800011dd3cb0 x8 : 000000000004e69b x7 : 0000000000000000 x6 : ffff0000f1926400 x5 : ffff0000f1940800 x4 : 0000000000000000 x3 : 0000000000000c40 x2 : 0000000000000008 x1 : 00000000002734d8 x0 : 0000000000000000 Call trace:
> __blkdev_issue_discard+0x200/0x294
> __submit_discard_cmd+0x128/0x374
> __issue_discard_cmd_orderly+0x188/0x244
> __issue_discard_cmd+0x2e8/0x33c
> issue_discard_thread+0xe8/0x2f0
> kthread+0x11c/0x120
> ret_from_fork+0x10/0x1c
> ---[ end trace e4c8023d33dfe77a ]---
>
> This patch fixes the issue by setting discard_granularity as SECTOR_SIZE
> instead of 0 when (card->pref_erase > max_discard) is true. Now no more
> complain from __blkdev_issue_discard() for the improper value of discard
> granularity.
>
> This issue is exposed after commit b35fd7422c2f ("block: check queue's
> limits.discard_granularity in __blkdev_issue_discard()"), a "Fixes:" tag
> is also added for the commit to make sure people won't miss this patch
> after applying the change of __blkdev_issue_discard().
>
> Fixes: e056a1b5b67b ("mmc: queue: let host controllers specify maximum discard timeout")
> Fixes: b35fd7422c2f ("block: check queue's limits.discard_granularity in __blkdev_issue_discard()").
> Reported-and-tested-by: Vicente Bergas <[email protected]>
> Signed-off-by: Coly Li <[email protected]>
> Acked-by: Adrian Hunter <[email protected]>
> Cc: Ulf Hansson <[email protected]>
While waiting for a new version that uses the logical block size, I
instead decided to apply this for fixes as is, thanks!
Please base the new version on top of this one instead.
Kind regards
Uffe
> ---
> Changelog,
> v4, update to Reported-and-tested-by tag for Vicente Bergas.
> v3, add Fixes tag for both commits.
> v2, change commit id of the Fixes tag.
> v1, initial version.
>
> drivers/mmc/core/queue.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
> index 6c022ef0f84d..350d0cc4ee62 100644
> --- a/drivers/mmc/core/queue.c
> +++ b/drivers/mmc/core/queue.c
> @@ -190,7 +190,7 @@ static void mmc_queue_setup_discard(struct request_queue *q,
> q->limits.discard_granularity = card->pref_erase << 9;
> /* granularity must not be greater than max. discard */
> if (card->pref_erase > max_discard)
> - q->limits.discard_granularity = 0;
> + q->limits.discard_granularity = SECTOR_SIZE;
> if (mmc_can_secure_erase_trim(card))
> blk_queue_flag_set(QUEUE_FLAG_SECERASE, q);
> }
> --
> 2.26.2
>