From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:36758 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727421AbeGSMpw (ORCPT ); Thu, 19 Jul 2018 08:45:52 -0400 Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 2169BAEDB for ; Thu, 19 Jul 2018 12:03:00 +0000 (UTC) Subject: Re: [PATCH 6/7] btrfs: drop extent_io_ops::merge_bio_hook callback To: David Sterba , linux-btrfs@vger.kernel.org References: <0e2c838370aab0b2da788a4c88174ec50979fc4c.1531996240.git.dsterba@suse.com> From: Nikolay Borisov Message-ID: Date: Thu, 19 Jul 2018 15:02:58 +0300 MIME-Version: 1.0 In-Reply-To: <0e2c838370aab0b2da788a4c88174ec50979fc4c.1531996240.git.dsterba@suse.com> Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 19.07.2018 14:05, David Sterba wrote: > The data and metadata callback implementation both use the same > function. We can remove the call indirection completely. > > Signed-off-by: David Sterba > --- > fs/btrfs/compression.c | 10 +++------- > fs/btrfs/disk-io.c | 2 -- > fs/btrfs/extent_io.c | 4 ++-- > fs/btrfs/extent_io.h | 3 --- > fs/btrfs/inode.c | 5 ++--- > 5 files changed, 7 insertions(+), 17 deletions(-) > > diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c > index 70dace47258b..9bfa66592aa7 100644 > --- a/fs/btrfs/compression.c > +++ b/fs/btrfs/compression.c > @@ -299,7 +299,6 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, > struct bio *bio = NULL; > struct compressed_bio *cb; > unsigned long bytes_left; > - struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > int pg_index = 0; > struct page *page; > u64 first_byte = disk_start; > @@ -338,9 +337,7 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, > page = compressed_pages[pg_index]; > page->mapping = inode->i_mapping; > if (bio->bi_iter.bi_size) > - submit = io_tree->ops->merge_bio_hook(page, 0, > - PAGE_SIZE, > - bio, 0); > + submit = btrfs_merge_bio_hook(page, 0, PAGE_SIZE, bio, 0); > > page->mapping = NULL; > if (submit || bio_add_page(bio, page, PAGE_SIZE, 0) < > @@ -622,9 +619,8 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, > page->index = em_start >> PAGE_SHIFT; > > if (comp_bio->bi_iter.bi_size) > - submit = tree->ops->merge_bio_hook(page, 0, > - PAGE_SIZE, > - comp_bio, 0); > + submit = btrfs_merge_bio_hook(page, 0, PAGE_SIZE, > + comp_bio, 0); > > page->mapping = NULL; > if (submit || bio_add_page(comp_bio, page, PAGE_SIZE, 0) < > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index d6c04933abbc..31ab764cf4e3 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -4527,8 +4527,6 @@ static const struct extent_io_ops btree_extent_io_ops = { > /* mandatory callbacks */ > .submit_bio_hook = btree_submit_bio_hook, > .readpage_end_io_hook = btree_readpage_end_io_hook, > - /* note we're sharing with inode.c for the merge bio hook */ > - .merge_bio_hook = btrfs_merge_bio_hook, > .readpage_io_failed_hook = btree_io_failed_hook, > .set_range_writeback = btrfs_set_range_writeback, > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index f7a138278f16..55a845621f85 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -2784,8 +2784,8 @@ static int submit_extent_page(unsigned int opf, struct extent_io_tree *tree, > else > contig = bio_end_sector(bio) == sector; > > - if (tree->ops && tree->ops->merge_bio_hook(page, offset, > - page_size, bio, bio_flags)) > + if (tree->ops && btrfs_merge_bio_hook(page, offset, page_size, > + bio, bio_flags)) While this is correct I dislike having the if (tree->ops ) check. So under what conditions do we NOT have the tree->ops set? Looking at the code it seems we are setting it everytime we create an inode in btrfs_create. We also set it for symlinks (btrfs_symlink) and a tmp file (btrfs_tmpfile). Strangely enough in btrfs_read_locked_inode we only set it for regular files (S_IFREG). submit_extent_page seems to be called for both metadata but as we no longer distinguish between eb merge_hook and data merge_hook perhaps the tree->ops could be killed as well ? > can_merge = false; > > if (prev_bio_flags != bio_flags || !contig || !can_merge || > diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h > index 6edbe01fd09d..ec7c4a2982d0 100644 > --- a/fs/btrfs/extent_io.h > +++ b/fs/btrfs/extent_io.h > @@ -101,9 +101,6 @@ struct extent_io_ops { > int (*readpage_end_io_hook)(struct btrfs_io_bio *io_bio, u64 phy_offset, > struct page *page, u64 start, u64 end, > int mirror); > - int (*merge_bio_hook)(struct page *page, unsigned long offset, > - size_t size, struct bio *bio, > - unsigned long bio_flags); > int (*readpage_io_failed_hook)(struct page *page, int failed_mirror); > void (*set_range_writeback)(void *private_data, u64 start, u64 end); > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 1614551cf953..845621a71468 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -1893,8 +1893,8 @@ static void btrfs_clear_bit_hook(void *private_data, > } > > /* > - * extent_io.c merge_bio_hook, this must check the chunk tree to make sure > - * we don't create bios that span stripes or chunks > + * Merge bio hook, this must check the chunk tree to make sure we don't create > + * bios that span stripes or chunks > * > * return 1 if page cannot be merged to bio > * return 0 if page can be merged to bio > @@ -10540,7 +10540,6 @@ static const struct extent_io_ops btrfs_extent_io_ops = { > /* mandatory callbacks */ > .submit_bio_hook = btrfs_submit_bio_hook, > .readpage_end_io_hook = btrfs_readpage_end_io_hook, > - .merge_bio_hook = btrfs_merge_bio_hook, > .readpage_io_failed_hook = btrfs_readpage_io_failed_hook, > .set_range_writeback = btrfs_set_range_writeback, > >