Re: [PATCH 2/2] iomap: simplify iomap_add_to_ioend
From: Matthew Wilcox <willy@infradead.org>
Date: 2021-07-20 12:10:38
On Tue, Jul 20, 2021 at 10:43:20AM +0200, Christoph Hellwig wrote:
Now that the outstanding writes are counted in bytes, there is no need to use the low-level __bio_try_merge_page API, we can switch back to always using bio_add_page and simply iomap_add_to_ioend again.
These two callers were the only external users of __bio_try_merge_page(), so it can now be made static to block/bio.c. From f3599f22b9e107c7a6cb0ace813ca505843316ce Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" <willy@infradead.org> Date: Tue, 20 Jul 2021 08:04:29 -0400 Subject: [PATCH] block: Make __bio_try_merge_page static iomap was the only external user of __bio_try_merge_page(). Make it static (and move it above a caller so it doesn't need to be declared in advance). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- block/bio.c | 77 ++++++++++++++++++++++----------------------- include/linux/bio.h | 2 -- 2 files changed, 38 insertions(+), 41 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 1fab762e079b..d36a4d3d3cd5 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -709,6 +709,44 @@ static inline bool page_is_mergeable(const struct bio_vec *bv, return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE); } +/** + * __bio_try_merge_page - try appending data to an existing bvec. + * @bio: destination bio + * @page: start page to add + * @len: length of the data to add + * @off: offset of the data relative to @page + * @same_page: return if the segment has been merged inside the same page + * + * Try to add the data at @page + @off to the last bvec of @bio. This is a + * useful optimisation for file systems with a block size smaller than the + * page size. + * + * Warn if (@len, @off) crosses pages in case that @same_page is true. + * + * Return %true on success or %false on failure. + */ +static bool __bio_try_merge_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int off, bool *same_page) +{ + if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) + return false; + + if (bio->bi_vcnt > 0) { + struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; + + if (page_is_mergeable(bv, page, len, off, same_page)) { + if (bio->bi_iter.bi_size > UINT_MAX - len) { + *same_page = false; + return false; + } + bv->bv_len += len; + bio->bi_iter.bi_size += len; + return true; + } + } + return false; +} + /* * Try to merge a page into a segment, while obeying the hardware segment * size limit. This is not for normal read/write bios, but for passthrough
@@ -840,45 +878,6 @@ int bio_add_zone_append_page(struct bio *bio, struct page *page, } EXPORT_SYMBOL_GPL(bio_add_zone_append_page); -/** - * __bio_try_merge_page - try appending data to an existing bvec. - * @bio: destination bio - * @page: start page to add - * @len: length of the data to add - * @off: offset of the data relative to @page - * @same_page: return if the segment has been merged inside the same page - * - * Try to add the data at @page + @off to the last bvec of @bio. This is a - * useful optimisation for file systems with a block size smaller than the - * page size. - * - * Warn if (@len, @off) crosses pages in case that @same_page is true. - * - * Return %true on success or %false on failure. - */ -bool __bio_try_merge_page(struct bio *bio, struct page *page, - unsigned int len, unsigned int off, bool *same_page) -{ - if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) - return false; - - if (bio->bi_vcnt > 0) { - struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; - - if (page_is_mergeable(bv, page, len, off, same_page)) { - if (bio->bi_iter.bi_size > UINT_MAX - len) { - *same_page = false; - return false; - } - bv->bv_len += len; - bio->bi_iter.bi_size += len; - return true; - } - } - return false; -} -EXPORT_SYMBOL_GPL(__bio_try_merge_page); - /** * __bio_add_page - add page(s) to a bio in a new segment * @bio: destination bio
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 2203b686e1f0..c779e0e3140a 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h@@ -467,8 +467,6 @@ extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, unsigned int, unsigned int); int bio_add_zone_append_page(struct bio *bio, struct page *page, unsigned int len, unsigned int offset); -bool __bio_try_merge_page(struct bio *bio, struct page *page, - unsigned int len, unsigned int off, bool *same_page); void __bio_add_page(struct bio *bio, struct page *page, unsigned int len, unsigned int off); int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
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2.30.2