When the added page is merged to last same page in bio_add_pc_page(),
the user may need to put this page for avoiding page leak.
bio_map_user_iov() needs this kind of handling, and now it deals with
it by itself in hack style.
Moves the handling of put page into __bio_add_pc_page(), so
bio_map_user_iov() may be simplified a bit, and maybe more users
can benefit from this change.
Cc: Omar Sandoval <osandov@xxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/bio.c | 23 ++++++++++-------------
include/linux/bio.h | 12 ++++++++++--
2 files changed, 20 insertions(+), 15 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 62411877224c..95ec5e893265 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -666,12 +666,13 @@ page_is_mergeable(const struct bio_vec *bv, struct page *page,
}
/**
- * bio_add_pc_page - attempt to add page to bio
+ * __bio_add_pc_page - attempt to add page to bio
* @q: the target queue
* @bio: destination bio
* @page: page to add
* @len: vec entry length
* @offset: vec entry offset
+ * @put_same_page: put the page if it is same with last added page
*
* Attempt to add a page to the bio_vec maplist. This can fail for a
* number of reasons, such as the bio being full or target block device
@@ -680,8 +681,9 @@ page_is_mergeable(const struct bio_vec *bv, struct page *page,
*
* This should only be used by REQ_PC bios.
*/
-int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
- *page, unsigned int len, unsigned int offset)
+int __bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
+ *page, unsigned int len, unsigned int offset,
+ bool put_same_page)
{
int retried_segments = 0;
struct bio_vec *bvec;
@@ -705,6 +707,8 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
if (page == prev->bv_page &&
offset == prev->bv_offset + prev->bv_len) {
+ if (put_same_page)
+ put_page(page);
prev->bv_len += len;
bio->bi_iter.bi_size += len;
goto done;
@@ -763,7 +767,7 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
blk_recount_segments(q, bio);
return 0;
}
-EXPORT_SYMBOL(bio_add_pc_page);
+EXPORT_SYMBOL(__bio_add_pc_page);
/**
* __bio_try_merge_page - try appending data to an existing bvec.
@@ -1394,21 +1398,14 @@ struct bio *bio_map_user_iov(struct request_queue *q,
for (j = 0; j < npages; j++) {
struct page *page = pages[j];
unsigned int n = PAGE_SIZE - offs;
- unsigned short prev_bi_vcnt = bio->bi_vcnt;
if (n > bytes)
n = bytes;
- if (!bio_add_pc_page(q, bio, page, n, offs))
+ if (!__bio_add_pc_page(q, bio, page, n, offs,
+ true))
break;
- /*
- * check if vector was merged with previous
- * drop page reference if needed
- */
- if (bio->bi_vcnt == prev_bi_vcnt)
- put_page(page);
-
added += n;
bytes -= n;
offs = 0;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index bb6090aa165d..28b8c46de11c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -430,8 +430,16 @@ extern void bio_reset(struct bio *);
void bio_chain(struct bio *, struct bio *);
extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
-extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
- unsigned int, unsigned int);
+extern int __bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
+ unsigned int, unsigned int, bool);
+
+static inline int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
+ *page, unsigned int len, unsigned int offset)
+{
+ return __bio_add_pc_page(q, bio, page, len, offset, false);
+}
+
+
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,
--
2.9.5
