@@ -283,6 +283,24 @@ out:
* @sdev: SCSI device associated with LUN.
* @lli: LUN destined for capacity request.
*
+ * The READ_CAP16 can take quite a while to complete. Should an EEH occur while
+ * in scsi_execute(), the EEH handler will attempt to recover. As part of the
+ * recovery, the handler drains all currently running ioctls, waiting until they
+ * have completed before proceeding with a reset. As this routine is used on the
+ * ioctl path, this can create a condition where the EEH handler becomes stuck,
+ * infinitely waiting for this ioctl thread. To avoid this behavior, temporarily
+ * unmark this thread as an ioctl thread by releasing the ioctl read semaphore.
+ * This will allow the EEH handler to proceed with a recovery while this thread
+ * is still running. Once the scsi_execute() returns, reacquire the ioctl read
+ * semaphore and check the adapter state in case it changed while inside of
+ * scsi_execute(). The state check will wait if the adapter is still being
+ * recovered or return a failure if the recovery failed. In the event that the
+ * adapter reset failed, simply return the failure as the ioctl would be unable
+ * to continue.
+ *
+ * Note that the above puts a requirement on this routine to only be called on
+ * an ioctl thread.
+ *
* Return: 0 on success, -errno on failure
*/
static int read_cap16(struct scsi_device *sdev, struct llun_info *lli)
@@ -314,8 +332,18 @@ retry:
dev_dbg(dev, "%s: %ssending cmd(0x%x)\n", __func__,
retry_cnt ? "re" : "", scsi_cmd[0]);
+ /* Drop the ioctl read semahpore across lengthy call */
+ up_read(&cfg->ioctl_rwsem);
result = scsi_execute(sdev, scsi_cmd, DMA_FROM_DEVICE, cmd_buf,
CMD_BUFSIZE, sense_buf, to, CMD_RETRIES, 0, NULL);
+ down_read(&cfg->ioctl_rwsem);
+ rc = check_state(cfg);
+ if (rc) {
+ dev_err(dev, "%s: Failed state! result=0x08%X\n",
+ __func__, result);
+ rc = -ENODEV;
+ goto out;
+ }
if (driver_byte(result) == DRIVER_SENSE) {
result &= ~(0xFF<<24); /* DRIVER_SENSE is not an error */
@@ -1221,7 +1249,7 @@ static const struct file_operations null_fops = {
*
* Return: 0 on success, -errno on failure
*/
-static int check_state(struct cxlflash_cfg *cfg)
+int check_state(struct cxlflash_cfg *cfg)
{
struct device *dev = &cfg->dev->dev;
int rc = 0;
@@ -147,4 +147,6 @@ void cxlflash_ba_terminate(struct ba_lun *);
int cxlflash_manage_lun(struct scsi_device *, struct dk_cxlflash_manage_lun *);
+int check_state(struct cxlflash_cfg *);
+
#endif /* ifndef _CXLFLASH_SUPERPIPE_H */
@@ -400,6 +400,24 @@ static int init_vlun(struct llun_info *lli)
* @lba: Logical block address to start write same.
* @nblks: Number of logical blocks to write same.
*
+ * The SCSI WRITE_SAME16 can take quite a while to complete. Should an EEH occur
+ * while in scsi_execute(), the EEH handler will attempt to recover. As part of
+ * the recovery, the handler drains all currently running ioctls, waiting until
+ * they have completed before proceeding with a reset. As this routine is used
+ * on the ioctl path, this can create a condition where the EEH handler becomes
+ * stuck, infinitely waiting for this ioctl thread. To avoid this behavior,
+ * temporarily unmark this thread as an ioctl thread by releasing the ioctl read
+ * semaphore. This will allow the EEH handler to proceed with a recovery while
+ * this thread is still running. Once the scsi_execute() returns, reacquire the
+ * ioctl read semaphore and check the adapter state in case it changed while
+ * inside of scsi_execute(). The state check will wait if the adapter is still
+ * being recovered or return a failure if the recovery failed. In the event that
+ * the adapter reset failed, simply return the failure as the ioctl would be
+ * unable to continue.
+ *
+ * Note that the above puts a requirement on this routine to only be called on
+ * an ioctl thread.
+ *
* Return: 0 on success, -errno on failure
*/
static int write_same16(struct scsi_device *sdev,
@@ -433,9 +451,20 @@ static int write_same16(struct scsi_device *sdev,
put_unaligned_be32(ws_limit < left ? ws_limit : left,
&scsi_cmd[10]);
+ /* Drop the ioctl read semahpore across lengthy call */
+ up_read(&cfg->ioctl_rwsem);
result = scsi_execute(sdev, scsi_cmd, DMA_TO_DEVICE, cmd_buf,
CMD_BUFSIZE, sense_buf, to, CMD_RETRIES,
0, NULL);
+ down_read(&cfg->ioctl_rwsem);
+ rc = check_state(cfg);
+ if (rc) {
+ dev_err(dev, "%s: Failed state! result=0x08%X\n",
+ __func__, result);
+ rc = -ENODEV;
+ goto out;
+ }
+
if (result) {
dev_err_ratelimited(dev, "%s: command failed for "
"offset %lld result=0x%x\n",