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block: move same page handling from __bio_add_pc_page to the callers 

Hiding page refcount manipulation inside a low-level bio helper is
somewhat awkward.  Instead return the same page information to the
callers, where it fits in much better.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2019-08-12 17:39:58 +02:00 committed by Jens Axboe
parent 384209cd5b
commit d1916c86cc
1 changed files with 10 additions and 10 deletions
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20
block/bio.c
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@ -669,7 +669,7 @@ static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *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
* @same_page: return if the merge happen inside the same 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
@ -680,10 +680,9 @@ static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio,
*/
static 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)
bool *same_page)
{
struct bio_vec *bvec;
bool same_page = false;
/*
* cloned bio must not modify vec list
@ -695,12 +694,8 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
return 0;
if (bio->bi_vcnt > 0) {
if (bio_try_merge_pc_page(q, bio, page, len, offset,
&same_page)) {
if (put_same_page && same_page)
put_page(page);
if (bio_try_merge_pc_page(q, bio, page, len, offset, same_page))
return len;
}
/*
* If the queue doesn't support SG gaps and adding this segment
@ -729,7 +724,8 @@ static int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
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 same_page = false;
return __bio_add_pc_page(q, bio, page, len, offset, &same_page);
}
EXPORT_SYMBOL(bio_add_pc_page);
@ -1373,13 +1369,17 @@ 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;
bool same_page = false;
if (n > bytes)
n = bytes;
if (!__bio_add_pc_page(q, bio, page, n, offs,
true))
&same_page)) {
if (same_page)
put_page(page);
break;
}
added += n;
bytes -= n;