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scsi: ufs: Request sense data asynchronously 

Clearing a unit attention synchronously from inside the UFS error handler
may trigger the following deadlock:

 - ufshcd_err_handler() calls ufshcd_err_handling_unprepare() and the
   latter function calls ufshcd_clear_ua_wluns().

 - ufshcd_clear_ua_wluns() submits a REQUEST SENSE command and that command
   activates the SCSI error handler.

 - The SCSI error handler calls ufshcd_host_reset_and_restore().

 - ufshcd_host_reset_and_restore() executes the following code:
   ufshcd_schedule_eh_work(hba); flush_work(&hba->eh_work);

This sequence results in a deadlock (circular wait). Fix this by requesting
sense data asynchronously.

Link: https://lore.kernel.org/r/20210722033439.26550-16-bvanassche@acm.org
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Can Guo <cang@codeaurora.org>
Cc: Asutosh Das <asutoshd@codeaurora.org>
Cc: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bart Van Assche 2021-07-21 20:34:36 -07:00 committed by Martin K. Petersen
parent 6418074260
commit ac1bc2ba06
1 changed files with 33 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
drivers/scsi/ufs/ufshcd.c
View File

@ -7880,8 +7880,39 @@ out:
return ret; return ret;
} }
static void ufshcd_request_sense_done(struct request *rq, blk_status_t error)
{
if (error != BLK_STS_OK)
pr_err("%s: REQUEST SENSE failed (%d)", __func__, error);
blk_put_request(rq);
}
static int static int
ufshcd_send_request_sense(struct ufs_hba *hba, struct scsi_device *sdp); ufshcd_request_sense_async(struct ufs_hba *hba, struct scsi_device *sdev)
{
/*
* From SPC-6: the REQUEST SENSE command with any allocation length
* clears the sense data.
*/
static const u8 cmd[6] = {REQUEST_SENSE, 0, 0, 0, 0, 0};
struct scsi_request *rq;
struct request *req;
req = blk_get_request(sdev->request_queue, REQ_OP_DRV_IN, /*flags=*/0);
if (IS_ERR(req))
return PTR_ERR(req);
rq = scsi_req(req);
rq->cmd_len = ARRAY_SIZE(cmd);
memcpy(rq->cmd, cmd, rq->cmd_len);
rq->retries = 3;
req->timeout = 1 * HZ;
req->rq_flags |= RQF_PM | RQF_QUIET;
blk_execute_rq_nowait(/*bd_disk=*/NULL, req, /*at_head=*/true,
ufshcd_request_sense_done);
return 0;
}
static int ufshcd_clear_ua_wlun(struct ufs_hba *hba, u8 wlun) static int ufshcd_clear_ua_wlun(struct ufs_hba *hba, u8 wlun)
{ {
@ -7909,7 +7940,7 @@ static int ufshcd_clear_ua_wlun(struct ufs_hba *hba, u8 wlun)
if (ret) if (ret)
goto out_err; goto out_err;
ret = ufshcd_send_request_sense(hba, sdp); ret = ufshcd_request_sense_async(hba, sdp);
scsi_device_put(sdp); scsi_device_put(sdp);
out_err: out_err:
if (ret) if (ret)
@ -8509,35 +8540,6 @@ static void ufshcd_hba_exit(struct ufs_hba *hba)
} }
} }
static int
ufshcd_send_request_sense(struct ufs_hba *hba, struct scsi_device *sdp)
{
unsigned char cmd[6] = {REQUEST_SENSE,
0,
0,
0,
UFS_SENSE_SIZE,
0};
char *buffer;
int ret;
buffer = kzalloc(UFS_SENSE_SIZE, GFP_KERNEL);
if (!buffer) {
ret = -ENOMEM;
goto out;
}
ret = scsi_execute(sdp, cmd, DMA_FROM_DEVICE, buffer,
UFS_SENSE_SIZE, NULL, NULL,
msecs_to_jiffies(1000), 3, 0, RQF_PM, NULL);
if (ret)
pr_err("%s: failed with err %d\n", __func__, ret);
kfree(buffer);
out:
return ret;
}
/** /**
* ufshcd_set_dev_pwr_mode - sends START STOP UNIT command to set device * ufshcd_set_dev_pwr_mode - sends START STOP UNIT command to set device
* power mode * power mode