block: rename __bio_add_pc_page to bio_add_hw_page

Rename __bio_add_pc_page() to bio_add_hw_page() and explicitly pass in a
max_sectors argument.

This max_sectors argument can be used to specify constraints from the
hardware.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[ jth: rebased and made public for blk-map.c ]
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bio.c b/block/bio.c
index 21cbaa6..aad0a6d 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -748,9 +748,14 @@ static inline bool page_is_mergeable(const struct bio_vec *bv,
        return true;
 }
 
-static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio,
-               struct page *page, unsigned len, unsigned offset,
-               bool *same_page)
+/*
+ * 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
+ * or Zone Append operations that we can't split.
+ */
+static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio,
+                                struct page *page, unsigned len,
+                                unsigned offset, bool *same_page)
 {
        struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
        unsigned long mask = queue_segment_boundary(q);
@@ -765,38 +770,32 @@ static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio,
 }
 
 /**
- *     __bio_add_pc_page       - attempt to add page to passthrough bio
- *     @q: the target queue
- *     @bio: destination bio
- *     @page: page to add
- *     @len: vec entry length
- *     @offset: vec entry offset
- *     @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
- *     limitations. The target block device must allow bio's up to PAGE_SIZE,
- *     so it is always possible to add a single page to an empty bio.
+ * bio_add_hw_page - attempt to add a page to a bio with hw constraints
+ * @q: the target queue
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ * @max_sectors: maximum number of sectors that can be added
+ * @same_page: return if the segment has been merged inside the same page
  *
- *     This should only be used by passthrough bios.
+ * Add a page to a bio while respecting the hardware max_sectors, max_segment
+ * and gap limitations.
  */
-int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
+int bio_add_hw_page(struct request_queue *q, struct bio *bio,
                struct page *page, unsigned int len, unsigned int offset,
-               bool *same_page)
+               unsigned int max_sectors, bool *same_page)
 {
        struct bio_vec *bvec;
 
-       /*
-        * cloned bio must not modify vec list
-        */
-       if (unlikely(bio_flagged(bio, BIO_CLONED)))
+       if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
                return 0;
 
-       if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
+       if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
                return 0;
 
        if (bio->bi_vcnt > 0) {
-               if (bio_try_merge_pc_page(q, bio, page, len, offset, same_page))
+               if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page))
                        return len;
 
                /*
@@ -823,11 +822,27 @@ int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
        return len;
 }
 
+/**
+ * bio_add_pc_page     - attempt to add page to passthrough bio
+ * @q: the target queue
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ *
+ * 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
+ * limitations. The target block device must allow bio's up to PAGE_SIZE,
+ * so it is always possible to add a single page to an empty bio.
+ *
+ * This should only be used by passthrough bios.
+ */
 int bio_add_pc_page(struct request_queue *q, struct bio *bio,
                struct page *page, unsigned int len, unsigned int offset)
 {
        bool same_page = false;
-       return __bio_add_pc_page(q, bio, page, len, offset, &same_page);
+       return bio_add_hw_page(q, bio, page, len, offset,
+                       queue_max_hw_sectors(q), &same_page);
 }
 EXPORT_SYMBOL(bio_add_pc_page);
 

diff --git a/block/blk-map.c b/block/blk-map.c
index b6fa343..e3e4ac4 100644 (file)
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -257,6 +257,7 @@ out_bmd:
 static struct bio *bio_map_user_iov(struct request_queue *q,
                struct iov_iter *iter, gfp_t gfp_mask)
 {
+       unsigned int max_sectors = queue_max_hw_sectors(q);
        int j;
        struct bio *bio;
        int ret;
@@ -294,8 +295,8 @@ static struct bio *bio_map_user_iov(struct request_queue *q,
                                if (n > bytes)
                                        n = bytes;
 
-                               if (!__bio_add_pc_page(q, bio, page, n, offs,
-                                               &same_page)) {
+                               if (!bio_add_hw_page(q, bio, page, n, offs,
+                                                    max_sectors, &same_page)) {
                                        if (same_page)
                                                put_page(page);
                                        break;

diff --git a/block/blk.h b/block/blk.h
index 8c3f557..e5cd350 100644 (file)
--- a/block/blk.h
+++ b/block/blk.h
@@ -452,8 +452,8 @@ static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
 
 struct request_queue *__blk_alloc_queue(int node_id);
 
-int __bio_add_pc_page(struct request_queue *q, struct bio *bio,
+int bio_add_hw_page(struct request_queue *q, struct bio *bio,
                struct page *page, unsigned int len, unsigned int offset,
-               bool *same_page);
+               unsigned int max_sectors, bool *same_page);
 
 #endif /* BLK_INTERNAL_H */