[PATCH 1/9] block: Convert various code to bio_for_each_segment()

Kent Overstreet
2013-11-04T23:36:47Z

With immutable biovecs we don't want code accessing bi_io_vec directly -
the uses this patch changes weren't incorrect since they all own the
bio, but it makes the code harder to audit for no good reason - also,
this will help with multipage bvecs later.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/btrfs/compression.c | 10 ++++------
fs/btrfs/disk-io.c | 11 ++++-------
fs/btrfs/extent_io.c | 37 ++++++++++++++-----------------------
fs/btrfs/inode.c | 15 ++++++---------
fs/f2fs/data.c | 13 +++++--------
fs/f2fs/segment.c | 12 +++++-------
fs/logfs/dev_bdev.c | 18 +++++++-----------
fs/mpage.c | 17 ++++++++---------
fs/nfs/blocklayout/blocklayout.c | 34 +++++++++++++---------------------
9 files changed, 66 insertions(+), 101 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 06ab821..52e7848 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -203,18 +203,16 @@ csum_failed:
if (cb->errors) {
bio_io_error(cb->orig_bio);
} else {
- int bio_index = 0;
- struct bio_vec *bvec = cb->orig_bio->bi_io_vec;
+ int i;
+ struct bio_vec *bvec;

/*
* we have verified the checksum already, set page
* checked so the end_io handlers know about it
*/
- while (bio_index < cb->orig_bio->bi_vcnt) {
+ bio_for_each_segment_all(bvec, cb->orig_bio, i)
SetPageChecked(bvec->bv_page);
- bvec++;
- bio_index++;
- }
+
bio_endio(cb->orig_bio, 0);
}

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 62176ad..733182e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -850,20 +850,17 @@ int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,

static int btree_csum_one_bio(struct bio *bio)
{
- struct bio_vec *bvec = bio->bi_io_vec;
- int bio_index = 0;
+ struct bio_vec *bvec;
struct btrfs_root *root;
- int ret = 0;
+ int i, ret = 0;

- WARN_ON(bio->bi_vcnt <= 0);
- while (bio_index < bio->bi_vcnt) {
+ bio_for_each_segment_all(bvec, bio, i) {
root = BTRFS_I(bvec->bv_page->mapping->host)->root;
ret = csum_dirty_buffer(root, bvec->bv_page);
if (ret)
break;
- bio_index++;
- bvec++;
}
+
return ret;
}

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0df176a..ea5a08b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2014,7 +2014,7 @@ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
}
bio->bi_bdev = dev->bdev;
bio_add_page(bio, page, length, start - page_offset(page));
- btrfsic_submit_bio(WRITE_SYNC, bio);
+ btrfsic_submit_bio(WRITE_SYNC, bio); /* XXX: submit_bio_wait() */
wait_for_completion(&compl);

if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
@@ -2340,12 +2340,13 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
*/
static void end_bio_extent_writepage(struct bio *bio, int err)
{
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct bio_vec *bvec;
struct extent_io_tree *tree;
u64 start;
u64 end;
+ int i;

- do {
+ bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;
tree = &BTRFS_I(page->mapping->host)->io_tree;

@@ -2363,14 +2364,11 @@ static void end_bio_extent_writepage(struct bio *bio, int err)
start = page_offset(page);
end = start + bvec->bv_offset + bvec->bv_len - 1;

- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
-
if (end_extent_writepage(page, err, start, end))
continue;

end_page_writeback(page);
- } while (bvec >= bio->bi_io_vec);
+ }

bio_put(bio);
}
@@ -2400,9 +2398,8 @@ endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
*/
static void end_bio_extent_readpage(struct bio *bio, int err)
{
+ struct bio_vec *bvec;
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
- struct bio_vec *bvec = bio->bi_io_vec;
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
struct extent_io_tree *tree;
u64 offset = 0;
@@ -2413,11 +2410,12 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
u64 extent_len = 0;
int mirror;
int ret;
+ int i;

if (err)
uptodate = 0;

- do {
+ bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;
struct inode *inode = page->mapping->host;

@@ -2441,9 +2439,6 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
end = start + bvec->bv_offset + bvec->bv_len - 1;
len = bvec->bv_len;

- if (++bvec <= bvec_end)
- prefetchw(&bvec->bv_page->flags);
-
mirror = io_bio->mirror_num;
if (likely(uptodate && tree->ops &&
tree->ops->readpage_end_io_hook)) {
@@ -2524,7 +2519,7 @@ readpage_ok:
extent_start = start;
extent_len = end + 1 - start;
}
- } while (bvec <= bvec_end);
+ }

if (extent_len)
endio_readpage_release_extent(tree, extent_start, extent_len,
@@ -2555,7 +2550,6 @@ btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
}

if (bio) {
- bio->bi_iter.bi_size = 0;
bio->bi_bdev = bdev;
bio->bi_iter.bi_sector = first_sector;
btrfs_bio = btrfs_io_bio(bio);
@@ -3418,20 +3412,18 @@ static void end_extent_buffer_writeback(struct extent_buffer *eb)

static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
{
- int uptodate = err == 0;
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct bio_vec *bvec;
struct extent_buffer *eb;
- int done;
+ int i, done;

- do {
+ bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;

- bvec--;
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
done = atomic_dec_and_test(&eb->io_pages);

- if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
+ if (err || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
ClearPageUptodate(page);
SetPageError(page);
@@ -3443,10 +3435,9 @@ static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
continue;

end_extent_buffer_writeback(eb);
- } while (bvec >= bio->bi_io_vec);
+ }

bio_put(bio);
-
}

static int write_one_eb(struct extent_buffer *eb,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6f5a64d..b7209a6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6765,17 +6765,16 @@ unlock_err:
static void btrfs_endio_direct_read(struct bio *bio, int err)
{
struct btrfs_dio_private *dip = bio->bi_private;
- struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
- struct bio_vec *bvec = bio->bi_io_vec;
+ struct bio_vec *bvec;
struct inode *inode = dip->inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct bio *dio_bio;
u32 *csums = (u32 *)dip->csum;
- int index = 0;
u64 start;
+ int i;

start = dip->logical_offset;
- do {
+ bio_for_each_segment_all(bvec, bio, i) {
if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
struct page *page = bvec->bv_page;
char *kaddr;
@@ -6791,18 +6790,16 @@ static void btrfs_endio_direct_read(struct bio *bio, int err)
local_irq_restore(flags);

flush_dcache_page(bvec->bv_page);
- if (csum != csums[index]) {
+ if (csum != csums[i]) {
btrfs_err(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
btrfs_ino(inode), start, csum,
- csums[index]);
+ csums[i]);
err = -EIO;
}
}

start += bvec->bv_len;
- bvec++;
- index++;
- } while (bvec <= bvec_end);
+ }

unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
dip->logical_offset + dip->bytes - 1);
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 97d8b34..dd02271 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -357,23 +357,20 @@ repeat:

static void read_end_io(struct bio *bio, int err)
{
- const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct bio_vec *bvec;
+ int i;

- do {
+ bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;

- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
-
- if (uptodate) {
+ if (!err) {
SetPageUptodate(page);
} else {
ClearPageUptodate(page);
SetPageError(page);
}
unlock_page(page);
- } while (bvec >= bio->bi_io_vec);
+ }
bio_put(bio);
}

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 9d77ce1..4382c90 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -575,16 +575,14 @@ static const struct segment_allocation default_salloc_ops = {

static void f2fs_end_io_write(struct bio *bio, int err)
{
- const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct bio_private *p = bio->bi_private;
+ struct bio_vec *bvec;
+ int i;

- do {
+ bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;

- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
- if (!uptodate) {
+ if (err) {
SetPageError(page);
if (page->mapping)
set_bit(AS_EIO, &page->mapping->flags);
@@ -593,7 +591,7 @@ static void f2fs_end_io_write(struct bio *bio, int err)
}
end_page_writeback(page);
dec_page_count(p->sbi, F2FS_WRITEBACK);
- } while (bvec >= bio->bi_io_vec);
+ }

if (p->is_sync)
complete(p->wait);
diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c
index a1b161f..ca42715 100644
--- a/fs/logfs/dev_bdev.c
+++ b/fs/logfs/dev_bdev.c
@@ -67,22 +67,18 @@ static DECLARE_WAIT_QUEUE_HEAD(wq);
static void writeseg_end_io(struct bio *bio, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct bio_vec *bvec;
+ int i;
struct super_block *sb = bio->bi_private;
struct logfs_super *super = logfs_super(sb);
- struct page *page;

BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */
BUG_ON(err);
- BUG_ON(bio->bi_vcnt == 0);
- do {
- page = bvec->bv_page;
- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
-
- end_page_writeback(page);
- page_cache_release(page);
- } while (bvec >= bio->bi_io_vec);
+
+ bio_for_each_segment_all(bvec, bio, i) {
+ end_page_writeback(bvec->bv_page);
+ page_cache_release(bvec->bv_page);
+ }
bio_put(bio);
if (atomic_dec_and_test(&super->s_pending_writes))
wake_up(&wq);
diff --git a/fs/mpage.c b/fs/mpage.c
index 92b125f..4979ffa 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -43,16 +43,14 @@
*/
static void mpage_end_io(struct bio *bio, int err)
{
- const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct bio_vec *bv;
+ int i;

- do {
- struct page *page = bvec->bv_page;
+ bio_for_each_segment_all(bv, bio, i) {
+ struct page *page = bv->bv_page;

- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
if (bio_data_dir(bio) == READ) {
- if (uptodate) {
+ if (!err) {
SetPageUptodate(page);
} else {
ClearPageUptodate(page);
@@ -60,14 +58,15 @@ static void mpage_end_io(struct bio *bio, int err)
}
unlock_page(page);
} else { /* bio_data_dir(bio) == WRITE */
- if (!uptodate) {
+ if (err) {
SetPageError(page);
if (page->mapping)
set_bit(AS_EIO, &page->mapping->flags);
}
end_page_writeback(page);
}
- } while (bvec >= bio->bi_io_vec);
+ }
+
bio_put(bio);
}

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index af73896..56ff823 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -202,18 +202,14 @@ static struct bio *bl_add_page_to_bio(struct bio *bio, int npg, int rw,
static void bl_end_io_read(struct bio *bio, int err)
{
struct parallel_io *par = bio->bi_private;
- const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+ struct bio_vec *bvec;
+ int i;

- do {
- struct page *page = bvec->bv_page;
+ if (!err)
+ bio_for_each_segment_all(bvec, bio, i)
+ SetPageUptodate(bvec->bv_page);

- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
- if (uptodate)
- SetPageUptodate(page);
- } while (bvec >= bio->bi_io_vec);
- if (!uptodate) {
+ if (err) {
struct nfs_read_data *rdata = par->data;
struct nfs_pgio_header *header = rdata->header;

@@ -384,20 +380,16 @@ static void mark_extents_written(struct pnfs_block_layout *bl,
static void bl_end_io_write_zero(struct bio *bio, int err)
{
struct parallel_io *par = bio->bi_private;
- const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
- struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-
- do {
- struct page *page = bvec->bv_page;
+ struct bio_vec *bvec;
+ int i;

- if (--bvec >= bio->bi_io_vec)
- prefetchw(&bvec->bv_page->flags);
+ bio_for_each_segment_all(bvec, bio, i) {
/* This is the zeroing page we added */
- end_page_writeback(page);
- page_cache_release(page);
- } while (bvec >= bio->bi_io_vec);
+ end_page_writeback(bvec->bv_page);
+ page_cache_release(bvec->bv_page);
+ }

- if (unlikely(!uptodate)) {
+ if (unlikely(err)) {
struct nfs_write_data *data = par->data;
struct nfs_pgio_header *header = data->header;

--
1.8.4.rc3