Re: [PATCH 0/7] Discard requests, v2

[OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>]

David Woodhouse <dwmw2@infradead.org> writes:

> On Mon, 2008-08-11 at 02:55 +0900, OGAWA Hirofumi wrote:
>> Or another options is caller should do? e.g. (WRITE | (1 <<
>> BIO_RW_DISCARD))
>
> Yeah, I thought about that. Figured it was better just to sort it out in
> submit_bio() rather than relying on the callers. Although admittedly
> there is precisely _one_ caller right now...

Although I don't have strong opinion, however, I've noticed
WRITE_BARRIER seems to be already doing similar thing.  So, I just
imaged it like following...  [I don't know whether blkdev_issue_flush()
really want to use (1 << BIO_RW_BARRIER) or not.]

diff -puN include/linux/fs.h~test include/linux/fs.h
--- linux-2.6/include/linux/fs.h~test	2008-08-11 06:22:38.000000000 +0900
+++ linux-2.6-hirofumi/include/linux/fs.h	2008-08-11 06:24:23.000000000 +0900
@@ -86,7 +86,8 @@ extern int dir_notify_enable;
 #define READ_META	(READ | (1 << BIO_RW_META))
 #define WRITE_SYNC	(WRITE | (1 << BIO_RW_SYNC))
 #define SWRITE_SYNC	(SWRITE | (1 << BIO_RW_SYNC))
-#define WRITE_BARRIER	((1 << BIO_RW) | (1 << BIO_RW_BARRIER))
+#define WRITE_BARRIER	(WRITE | (1 << BIO_RW_BARRIER))
+#define WRITE_DISCARD	(WRITE | (1 << BIO_RW_DISCARD))
 
 #define SEL_IN		1
 #define SEL_OUT		2
diff -puN block/blk-barrier.c~test block/blk-barrier.c
--- linux-2.6/block/blk-barrier.c~test	2008-08-11 06:29:13.000000000 +0900
+++ linux-2.6-hirofumi/block/blk-barrier.c	2008-08-11 06:30:16.000000000 +0900
@@ -293,7 +293,7 @@ int blkdev_issue_flush(struct block_devi
 	bio->bi_end_io = bio_end_empty_barrier;
 	bio->bi_private = &wait;
 	bio->bi_bdev = bdev;
-	submit_bio(1 << BIO_RW_BARRIER, bio);
+	submit_bio(WRITE_BARRIER, bio);
 
 	wait_for_completion(&wait);
 
_
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>