Hi Jinyoung,
can you work a bit on the commit log and especially the subject line?
I'd word this as something like:
"Subject: bio-integrity: create multi-page bvecs in bio_integrity_add_page()
Allow bio_integrity_add_page to create multi-page bvecs, just like
the bio payloads. This simplifies adding larger payloads, and fixes
support for non-tiny workloads with nvme, which stopped using scatterlist
for metadata a while ago"
It should probably also mentioned somewhere that you did an audit to
ensure all drivers and the core code is fine with these multi-page
segments. If it's not, this patch should only be added after that
has been made the case.
I think the extra arguments struct is a bit overcompliated, and mostly
due to me making the existing code to weird things in the low-level
helpers. With the "rationalize the flow in bio_add_page and friends"
series I just sent out, I think we can drop the previous patch and
simplify this one down to:
diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 4533eb49166109..85d70dc723f0ed 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -118,26 +118,44 @@ void bio_integrity_free(struct bio *bio)
* @len: number of bytes of integrity metadata in page
* @offset: start offset within page
*
- * Description: Attach a page containing integrity metadata to bio.
+ * Add a page containing integrity metadata to a bio while respecting
+ * the hardware max_sectors, max_segment and gap limitations.
*/
int bio_integrity_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int offset)
{
+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
struct bio_integrity_payload *bip = bio_integrity(bio);
- if (bip->bip_vcnt >= bip->bip_max_vcnt) {
- printk(KERN_ERR "%s: bip_vec full\n", __func__);
+ if (((bip->bip_iter.bi_size + len) >> SECTOR_SHIFT) >
+ queue_max_hw_sectors(q))
return 0;
- }
- if (bip->bip_vcnt &&
- bvec_gap_to_prev(&bdev_get_queue(bio->bi_bdev)->limits,
- &bip->bip_vec[bip->bip_vcnt - 1], offset))
- return 0;
+ if (bip->bip_vcnt > 0) {
+ struct bio_vec *bv = &bip->bip_vec[bip->bip_vcnt - 1];
+ bool same_page = false;
+
+ if (bvec_try_merge_hw_page(q, bv, page, len, offset,
+ &same_page)) {
+ bip->bip_iter.bi_size += len;
+ return len;
+ }
+
+ if (bip->bip_vcnt >=
+ min(bip->bip_max_vcnt, queue_max_integrity_segments(q)))
+ return 0;
+
+ /*
+ * If the queue doesn't support SG gaps and adding this segment
+ * would create a gap, disallow it.
+ */
+ if (bvec_gap_to_prev(&q->limits, bv, offset))
+ return 0;
+ }
bvec_set_page(&bip->bip_vec[bip->bip_vcnt], page, len, offset);
bip->bip_vcnt++;
-
+ bip->bip_iter.bi_size += len;
return len;
}
EXPORT_SYMBOL(bio_integrity_add_page);
@@ -249,7 +267,6 @@ bool bio_integrity_prep(struct bio *bio)
}
bip->bip_flags |= BIP_BLOCK_INTEGRITY;
- bip->bip_iter.bi_size = len;
bip_set_seed(bip, bio->bi_iter.bi_sector);
if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
diff --git a/block/bio.c b/block/bio.c
index 79e8aa600ddbe2..050b57e09ac362 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -934,7 +934,7 @@ static bool bvec_try_merge_page(struct bio_vec *bv, struct page *page,
* size limit. This is not for normal read/write bios, but for passthrough
* or Zone Append operations that we can't split.
*/
-static bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
+bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
struct page *page, unsigned len, unsigned offset,
bool *same_page)
{
diff --git a/block/blk.h b/block/blk.h
index 45547bcf111938..1e67f738b52191 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -486,4 +486,8 @@ static inline int req_ref_read(struct request *req)
return atomic_read(&req->ref);
}
+bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
+ struct page *page, unsigned len, unsigned offset,
+ bool *same_page);
+
#endif /* BLK_INTERNAL_H */
--
2.39.2
