Re: [PATCH v2] mmc: core: don't set limits.discard_granularity as 0

[Coly Li]

On 2020/10/1 15:13, Adrian Hunter wrote:
> On 1/10/20 9:59 am, Coly Li 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 explored after commit b35fd7422c2f ("block: check queue's
> 
> explored -> exposed
> 
>> limits.discard_granularity in __blkdev_issue_discard()"), therefore add
>> a "Fixes:" tag for the commit to make sure people won't miss this patch
>> after applying the change of __blkdev_issue_discard().
>>
>> Fixes: b35fd7422c2f ("block: check queue's limits.discard_granularity in __blkdev_issue_discard()").
> 
> I thought you would keep the other fixes tag also
> 
>> Reported-by: Vicente Bergas <vicencb@xxxxxxxxx>
>> Signed-off-by: Coly Li <colyli@xxxxxxx>
>> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> 
> Otherwise:
> 
> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

Copied, and thanks for your comments.

Coly Li