[PATCH/RESEND v8 2/4] block: Extend cmd_flags in struct request

From: Tanya Brokhman
Date: Sun Jun 09 2013 - 06:39:15 EST


At the moment no new request flags can be added to enum rq_flag_bits
due to cmd_flags field size limitation. This commit adds a new filed to be used as
an extensions to cmd_flags.

Signed-off-by: Tanya Brokhman <tlinder@xxxxxxxxxxxxxx>

diff --git a/block/blk-core.c b/block/blk-core.c
index fe3683c..3a14987 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3226,6 +3226,8 @@ int __init blk_dev_init(void)
{
BUILD_BUG_ON(__REQ_NR_BITS > 8 *
sizeof(((struct request *)0)->cmd_flags));
+ BUILD_BUG_ON(__REQ_EXT_NR_BITS > 8 *
+ sizeof(((struct request *)0)->cmd_flags_ext));

/* used for unplugging and affects IO latency/throughput - HIGHPRI */
kblockd_workqueue = alloc_workqueue("kblockd",
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index fa1abeb..40a921f 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -181,6 +181,11 @@ enum rq_flag_bits {
__REQ_NR_BITS, /* stops here */
};

+/* Request flags. For use in the cmd_flags_ext field of struct request */
+enum ext_rq_flag_bits {
+ __REQ_EXT_NR_BITS, /* stops here */
+};
+
#define REQ_WRITE (1 << __REQ_WRITE)
#define REQ_FAILFAST_DEV (1 << __REQ_FAILFAST_DEV)
#define REQ_FAILFAST_TRANSPORT (1 << __REQ_FAILFAST_TRANSPORT)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 968720f..aa36278 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -100,6 +100,7 @@ struct request {
struct request_queue *q;

unsigned int cmd_flags;
+ unsigned int cmd_flags_ext;
enum rq_cmd_type_bits cmd_type;
unsigned long atomic_flags;

--
1.7.6

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