[PATCH v5 1/3] scsi: scsi_ioctl: export __scsi_result_to_blk_status()

[mwilck@xxxxxxxx]

From: Martin Wilck <mwilck@xxxxxxxx>

This makes it possible to use scsi_result_to_blk_status() from
code that shouldn't depend on scsi_mod (e.g. device mapper).

scsi_ioctl.c is selected by CONFIG_BLK_SCSI_REQUEST, which is automatically
selected by CONFIG_SCSI.

Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
---
 block/scsi_ioctl.c      | 47 +++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/scsi_lib.c | 24 +--------------------
 include/linux/blkdev.h  |  1 +
 3 files changed, 49 insertions(+), 23 deletions(-)

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index fa6df11b8bdd..19b63b64ecbc 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -882,6 +882,53 @@ void scsi_req_init(struct scsi_request *req)
 }
 EXPORT_SYMBOL(scsi_req_init);
 
+/* See set_host_byte() in include/scsi/scsi_cmnd.h */
+static void __set_host_byte(int *result, char status)
+{
+	*result = (*result & 0xff00ffff) | (status << 16);
+}
+
+/**
+ * __scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
+ * @cmd:	SCSI command
+ * @cmd_result: pointer to scsi cmnd result code to be possibly changed
+ *
+ * Translate a SCSI result code into a blk_status_t value. May reset the host
+ * byte of @cmd_result.
+ */
+blk_status_t __scsi_result_to_blk_status(int *cmd_result, int result)
+{
+	switch (host_byte(result)) {
+	case DID_OK:
+		/*
+		 * Also check the other bytes than the status byte in result
+		 * to handle the case when a SCSI LLD sets result to
+		 * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
+		 */
+		if (scsi_status_is_good(result))
+			return BLK_STS_OK;
+		return BLK_STS_IOERR;
+	case DID_TRANSPORT_FAILFAST:
+	case DID_TRANSPORT_MARGINAL:
+		return BLK_STS_TRANSPORT;
+	case DID_TARGET_FAILURE:
+		__set_host_byte(cmd_result, DID_OK);
+		return BLK_STS_TARGET;
+	case DID_NEXUS_FAILURE:
+		__set_host_byte(cmd_result, DID_OK);
+		return BLK_STS_NEXUS;
+	case DID_ALLOC_FAILURE:
+		__set_host_byte(cmd_result, DID_OK);
+		return BLK_STS_NOSPC;
+	case DID_MEDIUM_ERROR:
+		__set_host_byte(cmd_result, DID_OK);
+		return BLK_STS_MEDIUM;
+	default:
+		return BLK_STS_IOERR;
+	}
+}
+EXPORT_SYMBOL(__scsi_result_to_blk_status);
+
 static int __init blk_scsi_ioctl_init(void)
 {
 	blk_set_cmd_filter_defaults(&blk_default_cmd_filter);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6b994baf87c2..2c0eca3693af 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -589,29 +589,7 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
  */
 static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
 {
-	switch (host_byte(result)) {
-	case DID_OK:
-		if (scsi_status_is_good(result))
-			return BLK_STS_OK;
-		return BLK_STS_IOERR;
-	case DID_TRANSPORT_FAILFAST:
-	case DID_TRANSPORT_MARGINAL:
-		return BLK_STS_TRANSPORT;
-	case DID_TARGET_FAILURE:
-		set_host_byte(cmd, DID_OK);
-		return BLK_STS_TARGET;
-	case DID_NEXUS_FAILURE:
-		set_host_byte(cmd, DID_OK);
-		return BLK_STS_NEXUS;
-	case DID_ALLOC_FAILURE:
-		set_host_byte(cmd, DID_OK);
-		return BLK_STS_NOSPC;
-	case DID_MEDIUM_ERROR:
-		set_host_byte(cmd, DID_OK);
-		return BLK_STS_MEDIUM;
-	default:
-		return BLK_STS_IOERR;
-	}
+	return __scsi_result_to_blk_status(&cmd->result, result);
 }
 
 /* Helper for scsi_io_completion() when "reprep" action required. */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1255823b2bc0..48497a77428d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -2021,4 +2021,5 @@ int fsync_bdev(struct block_device *bdev);
 int freeze_bdev(struct block_device *bdev);
 int thaw_bdev(struct block_device *bdev);
 
+blk_status_t __scsi_result_to_blk_status(int *cmd_result, int result);
 #endif /* _LINUX_BLKDEV_H */
-- 
2.32.0