2024-01-24 11:43:27

by John Garry

Subject: [PATCH v3 05/15] block: Add REQ_ATOMIC flag

From: Himanshu Madhani <[email protected]>

Add flag REQ_ATOMIC, meaning an atomic operation. This should only be
used in conjunction with REQ_OP_WRITE.

We will not add a special "request atomic write" operation, as to try to
avoid maintenance effort for an operation which is almost the same as
REQ_OP_WRITE.

Signed-off-by: Himanshu Madhani <[email protected]>
Signed-off-by: John Garry <[email protected]>
---
include/linux/blk_types.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index f288c94374b3..cd7cceb8565d 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -422,6 +422,7 @@ enum req_flag_bits {
__REQ_DRV, /* for driver use */
__REQ_FS_PRIVATE, /* for file system (submitter) use */

+ __REQ_ATOMIC, /* for atomic write operations */
/*
* Command specific flags, keep last:
*/
@@ -448,6 +449,7 @@ enum req_flag_bits {
#define REQ_RAHEAD (__force blk_opf_t)(1ULL << __REQ_RAHEAD)
#define REQ_BACKGROUND (__force blk_opf_t)(1ULL << __REQ_BACKGROUND)
#define REQ_NOWAIT (__force blk_opf_t)(1ULL << __REQ_NOWAIT)
+#define REQ_ATOMIC (__force blk_opf_t)(1ULL << __REQ_ATOMIC)
#define REQ_POLLED (__force blk_opf_t)(1ULL << __REQ_POLLED)
#define REQ_ALLOC_CACHE (__force blk_opf_t)(1ULL << __REQ_ALLOC_CACHE)
#define REQ_SWAP (__force blk_opf_t)(1ULL << __REQ_SWAP)
--
2.31.1

2024-02-13 06:24:49

by Christoph Hellwig

Subject: Re: [PATCH v3 05/15] block: Add REQ_ATOMIC flag

On Wed, Jan 24, 2024 at 11:38:31AM +0000, John Garry wrote:
> From: Himanshu Madhani <[email protected]>
>
> Add flag REQ_ATOMIC, meaning an atomic operation. This should only be
> used in conjunction with REQ_OP_WRITE.
>
> We will not add a special "request atomic write" operation, as to try to
> avoid maintenance effort for an operation which is almost the same as
> REQ_OP_WRITE.

I'd also merge this into the main atomic writes block layer patch..