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buffer: Convert block_read_full_folio to bh_submit()

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Avoid an extra indirect function call by using bh_submit() instead of
submit_bh().  Since mark_buffer_async_read() would collapse to a single
function call, inline it into block_read_full_folio() along with its
extensive comment.  Convert end_buffer_async_read_io() to
bh_end_async_read().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-11-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2026-05-28 18:31:23 +01:00 committed by Christian Brauner
parent 44d325ebba
commit 5059fb945c
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 32 additions and 33 deletions
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65
fs/buffer.c
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@ -402,11 +402,13 @@ static void decrypt_bh(struct work_struct *work)
}
/*
* I/O completion handler for block_read_full_folio() - pages
* I/O completion handler for block_read_full_folio() - folios
* which come unlocked at the end of I/O.
*/
static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate)
static void bh_end_async_read(struct bio *bio)
{
struct buffer_head *bh;
bool uptodate = bio_endio_bh(bio, &bh);
struct inode *inode = bh->b_folio->mapping->host;
bool decrypt = fscrypt_inode_uses_fs_layer_crypto(inode);
struct fsverity_info *vi = NULL;
@ -431,7 +433,7 @@ static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate)
}
return;
}
uptodate = 0;
uptodate = false;
}
end_buffer_async_read(bh, uptodate);
}
@ -494,33 +496,6 @@ void bh_end_async_write(struct bio *bio)
}
EXPORT_SYMBOL(bh_end_async_write);
/*
* If a page's buffers are under async readin (end_buffer_async_read
* completion) then there is a possibility that another thread of
* control could lock one of the buffers after it has completed
* but while some of the other buffers have not completed. This
* locked buffer would confuse end_buffer_async_read() into not unlocking
* the page. So the absence of BH_Async_Read tells end_buffer_async_read()
* that this buffer is not under async I/O.
*
* The page comes unlocked when it has no locked buffer_async buffers
* left.
*
* PageLocked prevents anyone starting new async I/O reads any of
* the buffers.
*
* PageWriteback is used to prevent simultaneous writeout of the same
* page.
*
* PageLocked prevents anyone from starting writeback of a page which is
* under read I/O (PageWriteback is only ever set against a locked page).
*/
static void mark_buffer_async_read(struct buffer_head *bh)
{
bh->b_end_io = end_buffer_async_read_io;
set_buffer_async_read(bh);
}
void mark_buffer_async_write(struct buffer_head *bh)
{
bh->b_end_io = end_buffer_async_write;
@ -2497,9 +2472,33 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block)
continue;
}
mark_buffer_async_read(bh);
/*
* If a folio's buffers are under async readin
* (end_buffer_async_read completion) then there is a
* possibility that another thread of control could lock
* one of the buffers after it has completed but while
* some of the other buffers have not completed. This
* locked buffer would confuse end_buffer_async_read()
* into not unlocking the folio. So the absence of
* BH_Async_Read tells end_buffer_async_read() that this
* buffer is not under async I/O.
*
* The folio comes unlocked when it has no locked
* buffer_async buffers left.
*
* The folio lock prevents anyone starting new async
* I/O reads into any of the buffers.
*
* The writeback flag is used to prevent simultaneous
* writeout of the same folio.
*
* The folio lock prevents anyone from starting writeback
* of a folio which is under read I/O (the writeback
* flag is only ever set on a locked folio).
*/
set_buffer_async_read(bh);
if (prev)
submit_bh(REQ_OP_READ, prev);
bh_submit(prev, REQ_OP_READ, bh_end_async_read);
prev = bh;
} while (iblock++, (bh = bh->b_this_page) != head);
@ -2513,7 +2512,7 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block)
* in this folio.
*/
if (prev)
submit_bh(REQ_OP_READ, prev);
bh_submit(prev, REQ_OP_READ, bh_end_async_read);
else
folio_end_read(folio, !page_error);