[PATCH V10 11/19] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()

2018-11-15 Thread Ming Lei 
bch_bio_alloc_pages() is always called on one new bio, so it is safe
to access the bvec table directly. Given it is the only kind of this
case, open code the bvec table access since bio_for_each_segment_all()
will be changed to support for iterating over multipage bvec.

Cc: Dave Chinner 
Cc: Kent Overstreet 
Acked-by: Coly Li 
Cc: Mike Snitzer 
Cc: dm-de...@redhat.com
Cc: Alexander Viro 
Cc: linux-fsde...@vger.kernel.org
Cc: Shaohua Li 
Cc: linux-r...@vger.kernel.org
Cc: linux-er...@lists.ozlabs.org
Cc: David Sterba 
Cc: linux-btrfs@vger.kernel.org
Cc: Darrick J. Wong 
Cc: linux-...@vger.kernel.org
Cc: Gao Xiang 
Cc: Christoph Hellwig 
Cc: Theodore Ts'o 
Cc: linux-e...@vger.kernel.org
Cc: Coly Li 
Cc: linux-bca...@vger.kernel.org
Cc: Boaz Harrosh 
Cc: Bob Peterson 
Cc: cluster-de...@redhat.com
Signed-off-by: Ming Lei 
---
 drivers/md/bcache/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index 20eddeac1531..8517aebcda2d 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -270,7 +270,7 @@ int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
int i;
struct bio_vec *bv;
 
-   bio_for_each_segment_all(bv, bio, i) {
+   for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++) {
bv->bv_page = alloc_page(gfp_mask);
if (!bv->bv_page) {
while (--bv >= bio->bi_io_vec)
-- 
2.9.5

Re: [PATCH V10 11/19] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()

2018-11-19 Thread Ming Lei 
On Thu, Nov 15, 2018 at 04:44:02PM -0800, Omar Sandoval wrote:
> On Thu, Nov 15, 2018 at 04:52:58PM +0800, Ming Lei wrote:
> > bch_bio_alloc_pages() is always called on one new bio, so it is safe
> > to access the bvec table directly. Given it is the only kind of this
> > case, open code the bvec table access since bio_for_each_segment_all()
> > will be changed to support for iterating over multipage bvec.
> > 
> > Cc: Dave Chinner 
> > Cc: Kent Overstreet 
> > Acked-by: Coly Li 
> > Cc: Mike Snitzer 
> > Cc: dm-de...@redhat.com
> > Cc: Alexander Viro 
> > Cc: linux-fsde...@vger.kernel.org
> > Cc: Shaohua Li 
> > Cc: linux-r...@vger.kernel.org
> > Cc: linux-er...@lists.ozlabs.org
> > Cc: David Sterba 
> > Cc: linux-btrfs@vger.kernel.org
> > Cc: Darrick J. Wong 
> > Cc: linux-...@vger.kernel.org
> > Cc: Gao Xiang 
> > Cc: Christoph Hellwig 
> > Cc: Theodore Ts'o 
> > Cc: linux-e...@vger.kernel.org
> > Cc: Coly Li 
> > Cc: linux-bca...@vger.kernel.org
> > Cc: Boaz Harrosh 
> > Cc: Bob Peterson 
> > Cc: cluster-de...@redhat.com
> > Signed-off-by: Ming Lei 
> > ---
> >  drivers/md/bcache/util.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
> > index 20eddeac1531..8517aebcda2d 100644
> > --- a/drivers/md/bcache/util.c
> > +++ b/drivers/md/bcache/util.c
> > @@ -270,7 +270,7 @@ int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
> > int i;
> > struct bio_vec *bv;
> >  
> > -   bio_for_each_segment_all(bv, bio, i) {
> > +   for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++) {
> 
> This is missing an i++.

Good catch, will fix it in next version.

thanks,
Ming

Re: [PATCH V10 11/19] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()

2018-11-19 Thread Ming Lei 
On Fri, Nov 16, 2018 at 02:46:45PM +0100, Christoph Hellwig wrote:
> > -   bio_for_each_segment_all(bv, bio, i) {
> > +   for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++) {
> 
> This really needs a comment.  Otherwise it looks fine to me.

OK, will do it in next version.

Thanks,
Ming

Re: [PATCH V10 11/19] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()

2018-11-15 Thread Omar Sandoval 
On Thu, Nov 15, 2018 at 04:52:58PM +0800, Ming Lei wrote:
> bch_bio_alloc_pages() is always called on one new bio, so it is safe
> to access the bvec table directly. Given it is the only kind of this
> case, open code the bvec table access since bio_for_each_segment_all()
> will be changed to support for iterating over multipage bvec.
> 
> Cc: Dave Chinner 
> Cc: Kent Overstreet 
> Acked-by: Coly Li 
> Cc: Mike Snitzer 
> Cc: dm-de...@redhat.com
> Cc: Alexander Viro 
> Cc: linux-fsde...@vger.kernel.org
> Cc: Shaohua Li 
> Cc: linux-r...@vger.kernel.org
> Cc: linux-er...@lists.ozlabs.org
> Cc: David Sterba 
> Cc: linux-btrfs@vger.kernel.org
> Cc: Darrick J. Wong 
> Cc: linux-...@vger.kernel.org
> Cc: Gao Xiang 
> Cc: Christoph Hellwig 
> Cc: Theodore Ts'o 
> Cc: linux-e...@vger.kernel.org
> Cc: Coly Li 
> Cc: linux-bca...@vger.kernel.org
> Cc: Boaz Harrosh 
> Cc: Bob Peterson 
> Cc: cluster-de...@redhat.com
> Signed-off-by: Ming Lei 
> ---
>  drivers/md/bcache/util.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
> index 20eddeac1531..8517aebcda2d 100644
> --- a/drivers/md/bcache/util.c
> +++ b/drivers/md/bcache/util.c
> @@ -270,7 +270,7 @@ int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
>   int i;
>   struct bio_vec *bv;
>  
> - bio_for_each_segment_all(bv, bio, i) {
> + for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++) {

This is missing an i++.

Re: [PATCH V10 11/19] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()

2018-11-16 Thread Christoph Hellwig 
> - bio_for_each_segment_all(bv, bio, i) {
> + for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++) {

This really needs a comment.  Otherwise it looks fine to me.