[PATCH v2 03/12] scsi: ufs: fix multiple ufs spec violation

From: Subhash Jadavani
Date: Tue Dec 13 2016 - 14:50:55 EST

From: Dolev Raviv <draviv@xxxxxxxxxxxxxx>

When a command to a W-LU is timed out via scsi, error handling
will treat it as any other LU and send commands such as
START_STOP with wrong format or task abort. Those commands are
illegal for W-LU according to the UFS spec.
To solve it, when an error is recognized those steps are skipped
and the last step, reset and restore process, is initiated.

Signed-off-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx>
Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
drivers/scsi/ufs/ufshcd.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 73c5937..f4cf66a 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -218,6 +218,7 @@ enum {
static void ufshcd_tmc_handler(struct ufs_hba *hba);
static void ufshcd_async_scan(void *data, async_cookie_t cookie);
static int ufshcd_reset_and_restore(struct ufs_hba *hba);
+static int ufshcd_eh_host_reset_handler(struct scsi_cmnd *cmd);
static int ufshcd_clear_tm_cmd(struct ufs_hba *hba, int tag);
static void ufshcd_hba_exit(struct ufs_hba *hba);
static int ufshcd_probe_hba(struct ufs_hba *hba);
@@ -4771,6 +4772,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
host = cmd->device->host;
hba = shost_priv(host);
tag = cmd->request->tag;
+ lrbp = &hba->lrb[tag];
if (!ufshcd_valid_tag(hba, tag)) {
"%s: invalid command tag %d: cmd=0x%p, cmd->request=0x%p",
@@ -4778,6 +4780,16 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)

+ /*
+ * Task abort to the device W-LUN is illegal. When this command
+ * will fail, due to spec violation, scsi err handling next step
+ * will be to send LU reset which, again, is a spec violation.
+ * To avoid these unnecessary/illegal step we skip to the last error
+ * handling stage: reset and restore.
+ */
+ if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN)
+ return ufshcd_eh_host_reset_handler(cmd);
ufshcd_hold(hba, false);
reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
/* If command is already aborted/completed, return SUCCESS */
@@ -4801,7 +4813,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
ufshcd_print_trs(hba, 1 << tag, true);

- lrbp = &hba->lrb[tag];
for (poll_cnt = 100; poll_cnt; poll_cnt--) {
err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
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