diff mbox

[v3,09/26] block: Remove bi_idx references

Message ID 1348526106-17074-10-git-send-email-koverstreet@google.com (mailing list archive)
State Deferred, archived
Headers show

Commit Message

Kent Overstreet Sept. 24, 2012, 10:34 p.m. UTC 
For immutable bvecs, all bi_idx usage needs to be audited - so here
we're removing all the unnecessary uses.

Most of these are places where it was being initialized on a bio that
was just allocated, a few others are conversions to standard macros.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
 drivers/block/aoe/aoeblk.c | 2 +-
 drivers/block/floppy.c     | 1 -
 drivers/md/dm-verity.c     | 2 +-
 drivers/md/raid10.c        | 1 -
 fs/buffer.c                | 1 -
 fs/jfs/jfs_logmgr.c        | 2 --
 fs/logfs/dev_bdev.c        | 5 -----
 mm/page_io.c               | 1 -
 8 files changed, 2 insertions(+), 13 deletions(-)

Comments

Vivek Goyal Oct. 2, 2012, 7:24 p.m. UTC | #1 
On Mon, Sep 24, 2012 at 03:34:49PM -0700, Kent Overstreet wrote:

[..]
> diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> index 95e52879..24e5cef 100644
> --- a/drivers/block/floppy.c
> +++ b/drivers/block/floppy.c
> @@ -3778,7 +3778,6 @@ static int __floppy_read_block_0(struct block_device *bdev)
>  	bio_vec.bv_len = size;
>  	bio_vec.bv_offset = 0;
>  	bio.bi_vcnt = 1;
> -	bio.bi_idx = 0;

So leaving bio.bi_idx uninitialized is safer than setting it to zero? Can
you explain a bit more that why this change is required? 

Thanks
Vivek

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Kent Overstreet Oct. 2, 2012, 8:16 p.m. UTC | #2 
On Tue, Oct 02, 2012 at 03:24:34PM -0400, Vivek Goyal wrote:
> On Mon, Sep 24, 2012 at 03:34:49PM -0700, Kent Overstreet wrote:
> 
> [..]
> > diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> > index 95e52879..24e5cef 100644
> > --- a/drivers/block/floppy.c
> > +++ b/drivers/block/floppy.c
> > @@ -3778,7 +3778,6 @@ static int __floppy_read_block_0(struct block_device *bdev)
> >  	bio_vec.bv_len = size;
> >  	bio_vec.bv_offset = 0;
> >  	bio.bi_vcnt = 1;
> > -	bio.bi_idx = 0;
> 
> So leaving bio.bi_idx uninitialized is safer than setting it to zero? Can
> you explain a bit more that why this change is required? 

It's not uninitialized, because it just called bio_init() - it was
entirely redundant before.

It's not strictly necessary, but immutable bio vecs require getting rid
of a lot of bi_idx usage, and everything that's left is either
unecessary or better/cleaner done some other way, so it's best to just
get rid of all of them - immutable bvecs changes the semantics of bi_idx
just enough that directly using it tends to be wrong.

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diff mbox

Patch

diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c
index 321de7b..6e4420a 100644
--- a/drivers/block/aoe/aoeblk.c
+++ b/drivers/block/aoe/aoeblk.c
@@ -199,7 +199,7 @@  aoeblk_make_request(struct request_queue *q, struct bio *bio)
 	buf->bio = bio;
 	buf->resid = bio->bi_size;
 	buf->sector = bio->bi_sector;
-	buf->bv = &bio->bi_io_vec[bio->bi_idx];
+	buf->bv = bio_iovec(bio);
 	buf->bv_resid = buf->bv->bv_len;
 	WARN_ON(buf->bv_resid == 0);
 	buf->bv_off = buf->bv->bv_offset;
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 95e52879..24e5cef 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -3778,7 +3778,6 @@  static int __floppy_read_block_0(struct block_device *bdev)
 	bio_vec.bv_len = size;
 	bio_vec.bv_offset = 0;
 	bio.bi_vcnt = 1;
-	bio.bi_idx = 0;
 	bio.bi_size = size;
 	bio.bi_bdev = bdev;
 	bio.bi_sector = 0;
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 8f95664..4431503 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -496,7 +496,7 @@  static int verity_map(struct dm_target *ti, struct bio *bio,
 
 	bio->bi_end_io = verity_end_io;
 	bio->bi_private = io;
-	io->io_vec_size = bio->bi_vcnt - bio->bi_idx;
+	io->io_vec_size = bio_segments(bio);
 	if (io->io_vec_size < DM_VERITY_IO_VEC_INLINE)
 		io->io_vec = io->io_vec_inline;
 	else
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index bbd08f5..6d06d83 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4249,7 +4249,6 @@  read_more:
 	read_bio->bi_flags &= ~(BIO_POOL_MASK - 1);
 	read_bio->bi_flags |= 1 << BIO_UPTODATE;
 	read_bio->bi_vcnt = 0;
-	read_bio->bi_idx = 0;
 	read_bio->bi_size = 0;
 	r10_bio->master_bio = read_bio;
 	r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
diff --git a/fs/buffer.c b/fs/buffer.c
index 58e2e7b..38d8793 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2893,7 +2893,6 @@  int submit_bh(int rw, struct buffer_head * bh)
 	bio->bi_io_vec[0].bv_offset = bh_offset(bh);
 
 	bio->bi_vcnt = 1;
-	bio->bi_idx = 0;
 	bio->bi_size = bh->b_size;
 
 	bio->bi_end_io = end_bio_bh_io_sync;
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 2eb952c..8ae5e35 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -2004,7 +2004,6 @@  static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
 
 	bio->bi_vcnt = 1;
-	bio->bi_idx = 0;
 	bio->bi_size = LOGPSIZE;
 
 	bio->bi_end_io = lbmIODone;
@@ -2145,7 +2144,6 @@  static void lbmStartIO(struct lbuf * bp)
 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
 
 	bio->bi_vcnt = 1;
-	bio->bi_idx = 0;
 	bio->bi_size = LOGPSIZE;
 
 	bio->bi_end_io = lbmIODone;
diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c
index e784a21..550475c 100644
--- a/fs/logfs/dev_bdev.c
+++ b/fs/logfs/dev_bdev.c
@@ -32,7 +32,6 @@  static int sync_request(struct page *page, struct block_device *bdev, int rw)
 	bio_vec.bv_len = PAGE_SIZE;
 	bio_vec.bv_offset = 0;
 	bio.bi_vcnt = 1;
-	bio.bi_idx = 0;
 	bio.bi_size = PAGE_SIZE;
 	bio.bi_bdev = bdev;
 	bio.bi_sector = page->index * (PAGE_SIZE >> 9);
@@ -108,7 +107,6 @@  static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
 		if (i >= max_pages) {
 			/* Block layer cannot split bios :( */
 			bio->bi_vcnt = i;
-			bio->bi_idx = 0;
 			bio->bi_size = i * PAGE_SIZE;
 			bio->bi_bdev = super->s_bdev;
 			bio->bi_sector = ofs >> 9;
@@ -136,7 +134,6 @@  static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
 		unlock_page(page);
 	}
 	bio->bi_vcnt = nr_pages;
-	bio->bi_idx = 0;
 	bio->bi_size = nr_pages * PAGE_SIZE;
 	bio->bi_bdev = super->s_bdev;
 	bio->bi_sector = ofs >> 9;
@@ -202,7 +199,6 @@  static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
 		if (i >= max_pages) {
 			/* Block layer cannot split bios :( */
 			bio->bi_vcnt = i;
-			bio->bi_idx = 0;
 			bio->bi_size = i * PAGE_SIZE;
 			bio->bi_bdev = super->s_bdev;
 			bio->bi_sector = ofs >> 9;
@@ -224,7 +220,6 @@  static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
 		bio->bi_io_vec[i].bv_offset = 0;
 	}
 	bio->bi_vcnt = nr_pages;
-	bio->bi_idx = 0;
 	bio->bi_size = nr_pages * PAGE_SIZE;
 	bio->bi_bdev = super->s_bdev;
 	bio->bi_sector = ofs >> 9;
diff --git a/mm/page_io.c b/mm/page_io.c
index 78eee32..8d3c0c0 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -35,7 +35,6 @@  static struct bio *get_swap_bio(gfp_t gfp_flags,
 		bio->bi_io_vec[0].bv_len = PAGE_SIZE;
 		bio->bi_io_vec[0].bv_offset = 0;
 		bio->bi_vcnt = 1;
-		bio->bi_idx = 0;
 		bio->bi_size = PAGE_SIZE;
 		bio->bi_end_io = end_io;
 	}