block: return on congested block device

[mirror_ubuntu-artful-kernel.git] / include / linux / blk_types.h

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index dcd45b15a3a5d670fcc7253eca615bef0860f154..e210da6d14b8fb55716e261724c9f623c8240e8f 100644 (file)
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -36,6 +36,8 @@ typedef u8 __bitwise blk_status_t;
 /* hack for device mapper, don't use elsewhere: */
 #define BLK_STS_DM_REQUEUE    ((__force blk_status_t)11)
 
+#define BLK_STS_AGAIN          ((__force blk_status_t)12)
+
 struct blk_issue_stat {
        u64 stat;
 };
@@ -224,6 +226,7 @@ enum req_flag_bits {
        /* command specific flags for REQ_OP_WRITE_ZEROES: */
        __REQ_NOUNMAP,          /* do not free blocks when zeroing */
 
+       __REQ_NOWAIT,           /* Don't wait if request will block */
        __REQ_NR_BITS,          /* stops here */
 };
 
@@ -242,6 +245,7 @@ enum req_flag_bits {
 #define REQ_BACKGROUND         (1ULL << __REQ_BACKGROUND)
 
 #define REQ_NOUNMAP            (1ULL << __REQ_NOUNMAP)
+#define REQ_NOWAIT             (1ULL << __REQ_NOWAIT)
 
 #define REQ_FAILFAST_MASK \
        (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)