[PATCH v2] block: unmap and free user mapped integrity via submitter

[Anuj Gupta]

The user mapped intergity is copied back and unpinned by
bio_integrity_free which is a low-level routine. Do it via the submitter
rather than doing it in the low-level block layer code, to split the
submitter side from the consumer side of the bio.

Signed-off-by: Anuj Gupta <anuj20.g at samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k at samsung.com>
---
Changes in v2:
- create a helper for unmap logic (Keith)
- return if integrity is not user-mapped (Jens)
- v1: https://lore.kernel.org/linux-block/20240510094429.2489-1-anuj20.g@samsung.com/
---
 block/bio-integrity.c     | 26 ++++++++++++++++++++++++--
 drivers/nvme/host/ioctl.c | 15 +++++++++++----
 include/linux/bio.h       |  4 ++++
 3 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 2e3e8e04961e..8b528e12136f 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -144,16 +144,38 @@ void bio_integrity_free(struct bio *bio)
 	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct bio_set *bs = bio->bi_pool;
 
+	if (bip->bip_flags & BIP_INTEGRITY_USER)
+		return;
 	if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
 		kfree(bvec_virt(bip->bip_vec));
-	else if (bip->bip_flags & BIP_INTEGRITY_USER)
-		bio_integrity_unmap_user(bip);
 
 	__bio_integrity_free(bs, bip);
 	bio->bi_integrity = NULL;
 	bio->bi_opf &= ~REQ_INTEGRITY;
 }
 
+/**
+ * bio_integrity_unmap_free_user - Unmap and free bio user integrity payload
+ * @bio:	bio containing bip to be unmapped and freed
+ *
+ * Description: Used to unmap and free the user mapped integrity portion of a
+ * bio. Submitter attaching the user integrity buffer is responsible for
+ * unmapping and freeing it during completion.
+ */
+void bio_integrity_unmap_free_user(struct bio *bio)
+{
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+	struct bio_set *bs = bio->bi_pool;
+
+	if (WARN_ON_ONCE(!(bip->bip_flags & BIP_INTEGRITY_USER)))
+		return;
+	bio_integrity_unmap_user(bip);
+	__bio_integrity_free(bs, bip);
+	bio->bi_integrity = NULL;
+	bio->bi_opf &= ~REQ_INTEGRITY;
+}
+EXPORT_SYMBOL(bio_integrity_unmap_free_user);
+
 /**
  * bio_integrity_add_page - Attach integrity metadata
  * @bio:	bio to update
diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 499a8bb7cac7..2dff5933cae9 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -111,6 +111,13 @@ static struct request *nvme_alloc_user_request(struct request_queue *q,
 	return req;
 }
 
+static void nvme_unmap_bio(struct bio *bio)
+{
+	if (bio_integrity(bio))
+		bio_integrity_unmap_free_user(bio);
+	blk_rq_unmap_user(bio);
+}
+
 static int nvme_map_user_request(struct request *req, u64 ubuffer,
 		unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
 		u32 meta_seed, struct io_uring_cmd *ioucmd, unsigned int flags)
@@ -157,7 +164,7 @@ static int nvme_map_user_request(struct request *req, u64 ubuffer,
 
 out_unmap:
 	if (bio)
-		blk_rq_unmap_user(bio);
+		nvme_unmap_bio(bio);
 out:
 	blk_mq_free_request(req);
 	return ret;
@@ -195,7 +202,7 @@ static int nvme_submit_user_cmd(struct request_queue *q,
 	if (result)
 		*result = le64_to_cpu(nvme_req(req)->result.u64);
 	if (bio)
-		blk_rq_unmap_user(bio);
+		nvme_unmap_bio(bio);
 	blk_mq_free_request(req);
 
 	if (effects)
@@ -406,7 +413,7 @@ static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd,
 	struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
 
 	if (pdu->bio)
-		blk_rq_unmap_user(pdu->bio);
+		nvme_unmap_bio(pdu->bio);
 	io_uring_cmd_done(ioucmd, pdu->status, pdu->result, issue_flags);
 }
 
@@ -432,7 +439,7 @@ static enum rq_end_io_ret nvme_uring_cmd_end_io(struct request *req,
 	 */
 	if (blk_rq_is_poll(req)) {
 		if (pdu->bio)
-			blk_rq_unmap_user(pdu->bio);
+			nvme_unmap_bio(pdu->bio);
 		io_uring_cmd_iopoll_done(ioucmd, pdu->result, pdu->status);
 	} else {
 		io_uring_cmd_do_in_task_lazy(ioucmd, nvme_uring_task_cb);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index d5379548d684..818e93612947 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -731,6 +731,7 @@ static inline bool bioset_initialized(struct bio_set *bs)
 		bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 
 int bio_integrity_map_user(struct bio *bio, void __user *ubuf, ssize_t len, u32 seed);
+void bio_integrity_unmap_free_user(struct bio *bio);
 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 extern bool bio_integrity_prep(struct bio *);
@@ -807,6 +808,9 @@ static inline int bio_integrity_map_user(struct bio *bio, void __user *ubuf,
 {
 	return -EINVAL;
 }
+static inline void bio_integrity_unmap_free_user(struct bio *bio)
+{
+}
 
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 
-- 
2.25.1