| Message ID | 20230919045135.3635437-5-willy@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Finish the create_empty_buffers() transition | expand |
On Tue, Sep 19, 2023 at 4:20 PM Matthew Wilcox (Oracle) wrote: > > Extract this useful helper from nilfs_page_get_nth_block() > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > fs/nilfs2/page.h | 7 +------ > include/linux/buffer_head.h | 22 ++++++++++++++++++++++ > 2 files changed, 23 insertions(+), 6 deletions(-) > > diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h > index 21ddcdd4d63e..344d71942d36 100644 > --- a/fs/nilfs2/page.h > +++ b/fs/nilfs2/page.h > @@ -55,12 +55,7 @@ unsigned long nilfs_find_uncommitted_extent(struct inode *inode, > static inline struct buffer_head * > nilfs_page_get_nth_block(struct page *page, unsigned int count) > { > - struct buffer_head *bh = page_buffers(page); > - > - while (count-- > 0) > - bh = bh->b_this_page; > - get_bh(bh); > - return bh; > + return get_nth_bh(page_buffers(page), count); > } > > #endif /* _NILFS_PAGE_H */ > diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h > index 1001244a8941..9fc615ee17fd 100644 > --- a/include/linux/buffer_head.h > +++ b/include/linux/buffer_head.h > @@ -457,6 +457,28 @@ __bread(struct block_device *bdev, sector_t block, unsigned size) > return __bread_gfp(bdev, block, size, __GFP_MOVABLE); > } > > +/** > + * get_nth_bh - Get a reference on the n'th buffer after this one. > + * @bh: The buffer to start counting from. > + * @count: How many buffers to skip. > + * > + * This is primarily useful for finding the nth buffer in a folio; in > + * that case you pass the head buffer and the byte offset in the folio > + * divided by the block size. It can be used for other purposes, but > + * it will wrap at the end of the folio rather than returning NULL or > + * proceeding to the next folio for you. > + * > + * Return: The requested buffer with an elevated refcount. > + */ > +static inline struct buffer_head *get_nth_bh(struct buffer_head *bh, > + unsigned int count) > +{ > + while (count--) > + bh = bh->b_this_page; > + get_bh(bh); > + return bh; > +} > + > bool block_dirty_folio(struct address_space *mapping, struct folio *folio); > > #ifdef CONFIG_BUFFER_HEAD > -- > 2.40.1 > Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Looks good to me. Thanks, Ryusuke Konishi
diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h index 21ddcdd4d63e..344d71942d36 100644 --- a/fs/nilfs2/page.h +++ b/fs/nilfs2/page.h @@ -55,12 +55,7 @@ unsigned long nilfs_find_uncommitted_extent(struct inode *inode, static inline struct buffer_head * nilfs_page_get_nth_block(struct page *page, unsigned int count) { - struct buffer_head *bh = page_buffers(page); - - while (count-- > 0) - bh = bh->b_this_page; - get_bh(bh); - return bh; + return get_nth_bh(page_buffers(page), count); } #endif /* _NILFS_PAGE_H */ diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 1001244a8941..9fc615ee17fd 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -457,6 +457,28 @@ __bread(struct block_device *bdev, sector_t block, unsigned size) return __bread_gfp(bdev, block, size, __GFP_MOVABLE); } +/** + * get_nth_bh - Get a reference on the n'th buffer after this one. + * @bh: The buffer to start counting from. + * @count: How many buffers to skip. + * + * This is primarily useful for finding the nth buffer in a folio; in + * that case you pass the head buffer and the byte offset in the folio + * divided by the block size. It can be used for other purposes, but + * it will wrap at the end of the folio rather than returning NULL or + * proceeding to the next folio for you. + * + * Return: The requested buffer with an elevated refcount. + */ +static inline struct buffer_head *get_nth_bh(struct buffer_head *bh, + unsigned int count) +{ + while (count--) + bh = bh->b_this_page; + get_bh(bh); + return bh; +} + bool block_dirty_folio(struct address_space *mapping, struct folio *folio); #ifdef CONFIG_BUFFER_HEAD
Extract this useful helper from nilfs_page_get_nth_block() Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- fs/nilfs2/page.h | 7 +------ include/linux/buffer_head.h | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+), 6 deletions(-)