block: don't allow multiple bio_iov_iter_get_pages calls per bio

No caller uses bio_iov_iter_get_pages multiple times on a given bio, and that funtionality isn't all that useful. Removing it will make some future changes a little easier and also simplifies the function a bit. Reviewed-by: Ming Lei <[email protected]> Reviewed-by: Bart Van Assche <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Reviewed-by: Johannes Thumshirn <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
CarlFK · Apr 12, 2019 · 14eacf1 · 14eacf1
1 parent a10584c
commit 14eacf1
Showing 1 changed file with 6 additions and 9 deletions.
diff --git a/block/bio.c b/block/bio.c
@@ -958,7 +958,10 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 {
 	const bool is_bvec = iov_iter_is_bvec(iter);
-	unsigned short orig_vcnt = bio->bi_vcnt;
+	int ret;
+
+	if (WARN_ON_ONCE(bio->bi_vcnt))
+		return -EINVAL;
 
 	/*
 	 * If this is a BVEC iter, then the pages are kernel pages. Don't
@@ -968,19 +971,13 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 		bio_set_flag(bio, BIO_NO_PAGE_REF);
 
 	do {
-		int ret;
-
 		if (is_bvec)
 			ret = __bio_iov_bvec_add_pages(bio, iter);
 		else
 			ret = __bio_iov_iter_get_pages(bio, iter);
+	} while (!ret && iov_iter_count(iter) && !bio_full(bio));
 
-		if (unlikely(ret))
-			return bio->bi_vcnt > orig_vcnt ? 0 : ret;
-
-	} while (iov_iter_count(iter) && !bio_full(bio));
-
-	return 0;
+	return bio->bi_vcnt ? 0 : ret;
 }
 
 static void submit_bio_wait_endio(struct bio *bio)