On 2012-07-30 23:39 Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Wrote: >On Mon, Jul 30, 2012 at 03:14:28PM +0800, majianpeng wrote: >> When exec bio_alloc, the bi_rw is zero.But after calling bio_add_page, > >What about submit_bio? That sets the bi_rw as well? >> it will use bi_rw. >> Fox example, in functiion __bio_add_page,it will call merge_bvec_fn(). > >function. >> The merge_bvec_fn of raid456 will use the bi_rw to judge the merge. >> >> if ((bvm->bi_rw & 1) == WRITE) >> >> return biovec->bv_len; /* always allow writes to be mergeable */ > >So what does that mean? Without this patch what happens? > Because bio_alloc, the bi_rw is zero default.But in __bio_add_page, it used bi_rw. For example: if merge_bvce_fn used bi_rw, but the bi_rw is wrong(if bi_rw is not zero). So the result may be error. >> >> >> Jianpeng Ma (8): > >Can you collapse all of this in just one patch? Sorry, I think those files are not a subsystem.So i should send separately. > >> Evalue bio->bi_rw after calling bio_alloc() and before calling > >It is 'evaluate' >> bio_add_page(). >> Evalue bio->bi_rw after calling bio_alloc() and before calling >> bio_add_page(). >> Evalue bio->bi_rw after calling bio_alloc() and before calling >> bio_add_page(). >> Evalue bio->bi_rw after calling bio_alloc() and before calling >> bio_add_page(). >> Evalue bio->bi_rw after calling bio_alloc() and before calling >> bio_add_page(). >> Evalue bio->bi_rw after calling bio_alloc() and before calling >> bio_add_page(). >> Evalue bio->bi_rw after calling bio_alloc() and before calling >> bio_add_page(). >> Evalue bio->bi_rw after calling bio_alloc() and before calling >> bio_add_page(). >> >> block/blk-lib.c | 1 + >> drivers/block/xen-blkback/blkback.c | 1 + > >I am not really sure if that is correct. Does 'submit_bio' not do the >job properly? Before call submit_bio, it call bio_add_page. > >> fs/btrfs/check-integrity.c | 1 + >> fs/direct-io.c | 1 + >> fs/ext4/page-io.c | 1 + >> fs/jfs/jfs_metapage.c | 1 + >> fs/ocfs2/cluster/heartbeat.c | 8 +++++--- >> fs/xfs/xfs_aops.c | 2 ++ >> fs/xfs/xfs_buf.c | 1 + >> 9 files changed, 14 insertions(+), 3 deletions(-) >> >> -- >> 1.7.9.5 _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
