On 4/27/20 1:31 PM, Johannes Thumshirn wrote:
From: Christoph Hellwig <hch@xxxxxx>
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@xxxxxx>
[ jth: rebased and made public for blk-map.c ]
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Reviewed-by: Daniel Wagner <dwagner@xxxxxxx>
---
block/bio.c | 60 +++++++++++++++++++++++++++----------------------
block/blk-map.c | 5 +++--
block/blk.h | 4 ++--
3 files changed, 38 insertions(+), 31 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 21cbaa6a1c20..0f0e337e46b4 100644
--- 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);
@@ -764,39 +769,24 @@ static bool bio_try_merge_pc_page(struct request_queue *q, struct bio *bio,
return __bio_try_merge_page(bio, page, len, offset, same_page);
}
-/**
- * __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.
- *
- * 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.
*/
Why did you drop to kerneldoc ?
If that's an internal function why isn't is marked as 'static'?
And if it's an exported one it certainly would warrant a kerneldoc
style comment ...
-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 +813,27 @@ 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 b6fa343fea9f..e3e4ac48db45 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -257,6 +257,7 @@ static struct bio *bio_copy_user_iov(struct request_queue *q,
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 73bd3b1c6938..1ae3279df712 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -453,8 +453,8 @@ 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 */
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
