[PATCH/RFC] Allowing REQ_FAILFAST to be set from SG_IO

[Hannes Reinecke <hare@suse.de>]

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Hi all,

this patch allows to set the REQ_FAILFAST flag to be set from SG_IO
commands. With it one can send generic SCSI commands which behave
exactly like normal requests send via the block layer.

Comments etc welcome.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke			hare@suse.de
SuSE Linux Products GmbH		S390 & zSeries
Maxfeldstraße 5				+49 911 74053 688
90409 Nürnberg				http://www.suse.de

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Allow FAILFAST flag to be set for SG_IO commands

This patch allows the FAILFAST flag to be set for SG_IO commands.

Signed-off-by: Hannes Reinecke <hare@suse.de>

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index b33eda2..658b1b5 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -295,6 +295,8 @@ static int sg_io(struct file *file, requ
 	rq->sense_len = 0;
 
 	rq->flags |= REQ_BLOCK_PC;
+	if (hdr->flags & SG_FLAGS_FAILFAST)
+		rq->flags |= REQ_FAILFAST;
 	bio = rq->bio;
 
 	/*
diff --git a/include/scsi/sg.h b/include/scsi/sg.h
index 0a487fe..9cc466a 100644
--- a/include/scsi/sg.h
+++ b/include/scsi/sg.h
@@ -142,6 +142,7 @@ typedef struct sg_io_hdr
 #define SG_FLAG_UNUSED_LUN_INHIBIT 2   /* default is overwrite lun in SCSI */
 				/* command block (when <= SCSI_2) */
 #define SG_FLAG_MMAP_IO 4       /* request memory mapped IO */
+#define SG_FLAG_FAILFAST 8      /* request should set FAILFAST flag */
 #define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */
 				/* user space (debug indirect IO) */