On 10/30/19 9:56 AM, Gao Xiang wrote:
Similar to [1] [2], it seems a trivial cleanup since
bio_alloc can handle memory allocation as mentioned in
fs/direct-io.c (also see fs/block_dev.c, fs/buffer.c, ..)
AFAIU, the reason is that, bio_alloc with __GFP_DIRECT_RECLAIM
flags guarantees bio allocation under some given restrictions,
as stated in fs/direct-io.c
So here it is ok to not check for NULL value from bio_alloc.
I think we can update above info too in your commit msg.
[1] https://lore.kernel.org/r/20191030035518.65477-1-gaoxiang25@xxxxxxxxxx
[2] https://lore.kernel.org/r/20190830162812.GA10694@xxxxxxxxxxxxx
Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx>
---
fs/ext4/page-io.c | 11 +++--------
fs/ext4/readpage.c | 2 --
2 files changed, 3 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 12ceadef32c5..f1f7b6601780 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -358,14 +358,12 @@ void ext4_io_submit_init(struct ext4_io_submit *io,
io->io_end = NULL;
}
-static int io_submit_init_bio(struct ext4_io_submit *io,
- struct buffer_head *bh)
+static void io_submit_init_bio(struct ext4_io_submit *io,
+ struct buffer_head *bh)
{
struct bio *bio;
bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
- if (!bio)
- return -ENOMEM;
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio_set_dev(bio, bh->b_bdev);
bio->bi_end_io = ext4_end_bio;
@@ -373,7 +371,6 @@ static int io_submit_init_bio(struct ext4_io_submit *io,
io->io_bio = bio;
io->io_next_block = bh->b_blocknr;
wbc_init_bio(io->io_wbc, bio);
- return 0;
}
static int io_submit_add_bh(struct ext4_io_submit *io,
@@ -388,9 +385,7 @@ static int io_submit_add_bh(struct ext4_io_submit *io,
ext4_io_submit(io);
}
if (io->io_bio == NULL) {
- ret = io_submit_init_bio(io, bh);
- if (ret)
- return ret;
+ io_submit_init_bio(io, bh);
io->io_bio->bi_write_hint = inode->i_write_hint;
}
ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
Also we can further simplify it like below. Please check.
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index f1f7b6601780..a3a2edeb3bbf 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -373,7 +373,7 @@ static void io_submit_init_bio(struct ext4_io_submit
*io,
wbc_init_bio(io->io_wbc, bio);
}
-static int io_submit_add_bh(struct ext4_io_submit *io,
+static void io_submit_add_bh(struct ext4_io_submit *io,
struct inode *inode,
struct page *page,
struct buffer_head *bh)
@@ -393,7 +393,6 @@ static int io_submit_add_bh(struct ext4_io_submit *io,
goto submit_and_retry;
wbc_account_cgroup_owner(io->io_wbc, page, bh->b_size);
io->io_next_block++;
- return 0;
}
int ext4_bio_write_page(struct ext4_io_submit *io,
@@ -495,30 +494,23 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
do {
if (!buffer_async_write(bh))
continue;
- ret = io_submit_add_bh(io, inode, bounce_page ?: page, bh);
- if (ret) {
- /*
- * We only get here on ENOMEM. Not much else
- * we can do but mark the page as dirty, and
- * better luck next time.
- */
- break;
- }
+ io_submit_add_bh(io, inode, bounce_page ?: page, bh);
nr_submitted++;
clear_buffer_dirty(bh);
} while ((bh = bh->b_this_page) != head);
- /* Error stopped previous loop? Clean up buffers... */
- if (ret) {
- out:
- fscrypt_free_bounce_page(bounce_page);
- printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
- redirty_page_for_writepage(wbc, page);
- do {
- clear_buffer_async_write(bh);
- bh = bh->b_this_page;
- } while (bh != head);
- }
+ goto unlock;
+
+out:
+ fscrypt_free_bounce_page(bounce_page);
+ printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
+ redirty_page_for_writepage(wbc, page);
+ do {
+ clear_buffer_async_write(bh);
+ bh = bh->b_this_page;
+ } while (bh != head);
+
+unlock:
unlock_page(page);
/* Nothing submitted - we have to end page writeback */
if (!nr_submitted)
-ritesh
