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-rw-r--r--block/bio.c60
1 files changed, 31 insertions, 29 deletions
diff --git a/block/bio.c b/block/bio.c
index 26853e072cd7..8d516d508ae3 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -665,6 +665,27 @@ static inline bool page_is_mergeable(const struct bio_vec *bv,
return true;
}
+/*
+ * Check if the @page can be added to the current segment(@bv), and make
+ * sure to call it only if page_is_mergeable(@bv, @page) is true
+ */
+static bool can_add_page_to_seg(struct request_queue *q,
+ struct bio_vec *bv, struct page *page, unsigned len,
+ unsigned offset)
+{
+ unsigned long mask = queue_segment_boundary(q);
+ phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset;
+ phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;
+
+ if ((addr1 | mask) != (addr2 | mask))
+ return false;
+
+ if (bv->bv_len + len > queue_max_segment_size(q))
+ return false;
+
+ return true;
+}
+
/**
* __bio_add_pc_page - attempt to add page to passthrough bio
* @q: the target queue
@@ -685,7 +706,6 @@ 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;
/*
@@ -709,6 +729,7 @@ int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
offset == bvec->bv_offset + bvec->bv_len) {
if (put_same_page)
put_page(page);
+ bvec_merge:
bvec->bv_len += len;
bio->bi_iter.bi_size += len;
goto done;
@@ -720,11 +741,18 @@ int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
*/
if (bvec_gap_to_prev(q, bvec, offset))
return 0;
+
+ if (page_is_mergeable(bvec, page, len, offset, false) &&
+ can_add_page_to_seg(q, bvec, page, len, offset))
+ goto bvec_merge;
}
if (bio_full(bio))
return 0;
+ if (bio->bi_phys_segments >= queue_max_segments(q))
+ return 0;
+
/*
* setup the new entry, we might clear it again later if we
* cannot add the page
@@ -734,38 +762,12 @@ int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
bvec->bv_len = len;
bvec->bv_offset = offset;
bio->bi_vcnt++;
- bio->bi_phys_segments++;
bio->bi_iter.bi_size += len;
- /*
- * Perform a recount if the number of segments is greater
- * than queue_max_segments(q).
- */
-
- while (bio->bi_phys_segments > queue_max_segments(q)) {
-
- if (retried_segments)
- goto failed;
-
- retried_segments = 1;
- blk_recount_segments(q, bio);
- }
-
- /* If we may be able to merge these biovecs, force a recount */
- if (bio->bi_vcnt > 1 && biovec_phys_mergeable(q, bvec - 1, bvec))
- bio_clear_flag(bio, BIO_SEG_VALID);
-
done:
+ bio->bi_phys_segments = bio->bi_vcnt;
+ bio_set_flag(bio, BIO_SEG_VALID);
return len;
-
- failed:
- bvec->bv_page = NULL;
- bvec->bv_len = 0;
- bvec->bv_offset = 0;
- bio->bi_vcnt--;
- bio->bi_iter.bi_size -= len;
- blk_recount_segments(q, bio);
- return 0;
}
EXPORT_SYMBOL(__bio_add_pc_page);