Re: [PATCH] REQ-flags to/from BIO-flags bugfix

[Matthew Wilcox <matthew@wil.cx>]

On Wed, Dec 12, 2007 at 08:18:14AM -0700, Matthew Wilcox wrote:
> I don't know whether BIO_RW_BARRIER is __REQ_SOFTBARRIER or
> __REQ_HARDBARRIER, so I didn't include that in this patch.  There also
> doesn't seem to be a __REQ equivalent to BIO_RW_AHEAD, but we can do
> the other four bits (and leave gaps for those two).

Hm.  BIO_RW_AHEAD seems unused:

willy@honeydew:~/kernel/linux-2.6$ grep -r BIO_RW_AHEAD *
block/blktrace.c:       (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD))
include/linux/bio.h:#define BIO_RW_AHEAD        1
include/linux/bio.h:#define bio_rw_ahead(bio)   ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
willy@honeydew:~/kernel/linux-2.6$ grep -r bio_rw_ahead *
block/ll_rw_blk.c:      if (bio_rw_ahead(bio) || bio_failfast(bio))
drivers/md/dm-mpath.c:  if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
drivers/md/multipath.c: else if (!bio_rw_ahead(bio)) {
include/linux/bio.h:#define bio_rw_ahead(bio)   ((bio)->bi_rw & (1 << BIO_RW_AHEAD))

BIO_RW_BARRIER seems to be __REQ_HARDBARRIER, but we set it
explicitly in init_request_from_bio().  We could probably simplify
init_request_from_bio() with the patch in the previous message.

-- 
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