block: remove the BIO_USER_MAPPED flag

Just check if there is private data, in which case the bio must have
originated from bio_copy_user_iov.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-map.c

@@ -109,7 +109,7 @@ static int bio_uncopy_user(struct bio *bio)
 	struct bio_map_data *bmd = bio->bi_private;
 	int ret = 0;
 
-	if (!bmd || !bmd->is_null_mapped) {
+	if (!bmd->is_null_mapped) {
 		/*
 		 * if we're in a workqueue, the request is orphaned, so
 		 * don't copy into a random user address space, just free
@@ -307,8 +307,6 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
 			break;
 	}
 
-	bio_set_flag(bio, BIO_USER_MAPPED);
-
 	/*
 	 * Subtle: if we end up needing to bounce a bio, it would normally
 	 * disappear when its bi_end_io is run.  However, we need the original
@@ -654,12 +652,12 @@ int blk_rq_unmap_user(struct bio *bio)
 		if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
 			mapped_bio = bio->bi_private;
 
-		if (bio_flagged(mapped_bio, BIO_USER_MAPPED)) {
-			bio_unmap_user(mapped_bio);
-		} else {
+		if (bio->bi_private) {
 			ret2 = bio_uncopy_user(mapped_bio);
 			if (ret2 && !ret)
 				ret = ret2;
+		} else {
+			bio_unmap_user(mapped_bio);
 		}
 
 		mapped_bio = bio;

include/linux/blk_types.h

@@ -256,7 +256,6 @@ enum {
 	BIO_NO_PAGE_REF,	/* don't put release vec pages */
 	BIO_CLONED,		/* doesn't own data */
 	BIO_BOUNCED,		/* bio is a bounce bio */
-	BIO_USER_MAPPED,	/* contains user pages */
 	BIO_WORKINGSET,		/* contains userspace workingset pages */
 	BIO_QUIET,		/* Make BIO Quiet */
 	BIO_CHAIN,		/* chained bio, ->bi_remaining in effect */