From: Bart Van Assche bvanassche@acm.org
[ Upstream commit ac1bc2ba060f9609972fb486073ebd9eab1ef3b6 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/ufs/ufshcd.c | 64 ++++++++++++++++++++------------------- 1 file changed, 33 insertions(+), 31 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 469a7be270d6..1f0980a70e3f 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -7784,8 +7784,39 @@ static int ufshcd_add_lus(struct ufs_hba *hba) 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 -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) { @@ -7813,7 +7844,7 @@ static int ufshcd_clear_ua_wlun(struct ufs_hba *hba, u8 wlun) if (ret) goto out_err;
- ret = ufshcd_send_request_sense(hba, sdp); + ret = ufshcd_request_sense_async(hba, sdp); scsi_device_put(sdp); out_err: if (ret) @@ -8407,35 +8438,6 @@ 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 * power mode