block: don't free submitter owned integrity payload on I/O completion

Currently __bio_integrity_endio frees the integrity payload unless it is
explicitly marked as user-mapped.  This means in-kernel callers that
allocate their own integrity payload never get to see it on I/O
completion.  The current two users don't need it as they just pre-mapped
PI tuples received over the network, but this limits uses of integrity
data lot.

Change bio_integrity_endio to call __bio_integrity_endio for block layer
generated integrity data only, and leave freeing of submitter
allocated integrity data to bio_uninit which also gets called from
the final bio_put.  This requires that unmapping user mapped or copied
integrity data is now always done by the caller, and the special
BIP_INTEGRITY_USER flag can go away.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Reviewed-by: Kanchan Joshi <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Christoph Hellwig

block/bio-integrity.c

@@ -22,9 +22,17 @@ void blk_flush_integrity(void)
 	flush_workqueue(kintegrityd_wq);
 }
 
-static void __bio_integrity_free(struct bio_set *bs,
-				 struct bio_integrity_payload *bip)
+/**
+ * bio_integrity_free - Free bio integrity payload
+ * @bio:	bio containing bip to be freed
+ *
+ * Description: Free the integrity portion of a bio.
+ */
+void bio_integrity_free(struct bio *bio)
 {
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+	struct bio_set *bs = bio->bi_pool;
+
 	if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
 		if (bip->bip_vec)
 			bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
@@ -33,6 +41,8 @@ static void __bio_integrity_free(struct bio_set *bs,
 	} else {
 		kfree(bip);
 	}
+	bio->bi_integrity = NULL;
+	bio->bi_opf &= ~REQ_INTEGRITY;
 }
 
 /**
@@ -86,7 +96,10 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 
 	return bip;
 err:
-	__bio_integrity_free(bs, bip);
+	if (bs && mempool_initialized(&bs->bio_integrity_pool))
+		mempool_free(bip, &bs->bio_integrity_pool);
+	else
+		kfree(bip);
 	return ERR_PTR(-ENOMEM);
 }
 EXPORT_SYMBOL(bio_integrity_alloc);
@@ -132,28 +145,6 @@ static void bio_integrity_unmap_user(struct bio_integrity_payload *bip)
 	bio_integrity_unpin_bvec(bip->bip_vec, bip->bip_max_vcnt, dirty);
 }
 
-/**
- * bio_integrity_free - Free bio integrity payload
- * @bio:	bio containing bip to be freed
- *
- * Description: Used to free the integrity portion of a bio. Usually
- * called from bio_free().
- */
-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));
-
-	__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
@@ -165,14 +156,9 @@ void bio_integrity_free(struct bio *bio)
 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;
+	bio_integrity_free(bio);
 }
 
 /**
@@ -273,7 +259,7 @@ static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
 		goto free_bip;
 	}
 
-	bip->bip_flags |= BIP_INTEGRITY_USER | BIP_COPY_USER;
+	bip->bip_flags |= BIP_COPY_USER;
 	bip->bip_iter.bi_sector = seed;
 	bip->bip_vcnt = nr_vecs;
 	return 0;
@@ -294,7 +280,6 @@ static int bio_integrity_init_user(struct bio *bio, struct bio_vec *bvec,
 		return PTR_ERR(bip);
 
 	memcpy(bip->bip_vec, bvec, nr_vecs * sizeof(*bvec));
-	bip->bip_flags |= BIP_INTEGRITY_USER;
 	bip->bip_iter.bi_sector = seed;
 	bip->bip_iter.bi_size = len;
 	bip->bip_vcnt = nr_vecs;
@@ -502,6 +487,8 @@ static void bio_integrity_verify_fn(struct work_struct *work)
 	struct bio *bio = bip->bip_bio;
 
 	blk_integrity_verify(bio);
+
+	kfree(bvec_virt(bip->bip_vec));
 	bio_integrity_free(bio);
 	bio_endio(bio);
 }
@@ -522,13 +509,13 @@ bool __bio_integrity_endio(struct bio *bio)
 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 	struct bio_integrity_payload *bip = bio_integrity(bio);
 
-	if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
-	    (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->csum_type) {
+	if (bio_op(bio) == REQ_OP_READ && !bio->bi_status && bi->csum_type) {
 		INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
 		queue_work(kintegrityd_wq, &bip->bip_work);
 		return false;
 	}
 
+	kfree(bvec_virt(bip->bip_vec));
 	bio_integrity_free(bio);
 	return true;
 }

block/blk.h

@@ -202,11 +202,20 @@ static inline unsigned int blk_queue_get_max_sectors(struct request *rq)
 
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 void blk_flush_integrity(void);
-bool __bio_integrity_endio(struct bio *);
 void bio_integrity_free(struct bio *bio);
+
+/*
+ * Integrity payloads can either be owned by the submitter, in which case
+ * bio_uninit will free them, or owned and generated by the block layer,
+ * in which case we'll verify them here (for reads) and free them before
+ * the bio is handed back to the submitted.
+ */
+bool __bio_integrity_endio(struct bio *bio);
 static inline bool bio_integrity_endio(struct bio *bio)
 {
-	if (bio_integrity(bio))
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+
+	if (bip && (bip->bip_flags & BIP_BLOCK_INTEGRITY))
 		return __bio_integrity_endio(bio);
 	return true;
 }

include/linux/bio-integrity.h

@@ -10,8 +10,7 @@ enum bip_flags {
 	BIP_CTRL_NOCHECK	= 1 << 2, /* disable HBA integrity checking */
 	BIP_DISK_NOCHECK	= 1 << 3, /* disable disk integrity checking */
 	BIP_IP_CHECKSUM		= 1 << 4, /* IP checksum */
-	BIP_INTEGRITY_USER	= 1 << 5, /* Integrity payload is user address */
-	BIP_COPY_USER		= 1 << 6, /* Kernel bounce buffer in use */
+	BIP_COPY_USER		= 1 << 5, /* Kernel bounce buffer in use */
 };
 
 struct bio_integrity_payload {