[PATCH 1/3] block: Add error codes for common PR failures

[Mike Christie <michael.christie@oracle.com>]

If a PR operation fails we can return a device specific error which is
impossible to handle in some cases because we could have a mix of devices
when DM is used, or future users like lio only know it's interacting with
a block device so it doesn't know the type.

This patch adds a new pr_status enum so drivers can convert errors to a
common type which can be handled by the caller.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 include/uapi/linux/pr.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/include/uapi/linux/pr.h b/include/uapi/linux/pr.h
index ccc78cbf1221..16b856fb8053 100644
--- a/include/uapi/linux/pr.h
+++ b/include/uapi/linux/pr.h
@@ -4,6 +4,30 @@
 
 #include <linux/types.h>
 
+enum pr_status {
+	PR_STS_SUCCESS			= 0x0,
+	/*
+	 * These error codes have no mappings to existing SCSI errors.
+	 */
+	/* The request is not supported. */
+	PR_STS_OP_NOT_SUPP		= 0x7fffffff,
+	/* The request is invalid/illegal. */
+	PR_STS_OP_INVALID		= 0x7ffffffe,
+	/*
+	 * The following error codes are based on SCSI, because the interface
+	 * was originally created for it and has existing users.
+	 */
+	/* Generic device failure. */
+	PR_STS_IOERR			= 0x2,
+	PR_STS_RESERVATION_CONFLICT	= 0x18,
+	/* Temporary path failure that can be retried. */
+	PR_STS_RETRY_PATH_FAILURE	= 0xe0000,
+	/* The request was failed due to a fast failure timer. */
+	PR_STS_PATH_FAST_FAILED		= 0xf0000,
+	/* The path cannot be reached and has been marked as failed. */
+	PR_STS_PATH_FAILED		= 0x10000,
+};
+
 enum pr_type {
 	PR_WRITE_EXCLUSIVE		= 1,
 	PR_EXCLUSIVE_ACCESS		= 2,
-- 
2.25.1