Revert "bio: limit bio max size"

This reverts commit cd2c7545ae.

Alex reports that the commit causes corruption with LUKS on ext4. Revert
it for now so that this can be investigated properly.

Link: https://lore.kernel.org/linux-block/1620493841.bxdq8r5haw.none@localhost/
Reported-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bio.c

@@ -255,13 +255,6 @@ void bio_init(struct bio *bio, struct bio_vec *table,
 }
 EXPORT_SYMBOL(bio_init);
 
-unsigned int bio_max_size(struct bio *bio)
-{
-	struct block_device *bdev = bio->bi_bdev;
-
-	return bdev ? bdev->bd_disk->queue->limits.bio_max_bytes : UINT_MAX;
-}
-
 /**
  * bio_reset - reinitialize a bio
  * @bio:	bio to reset
@@ -873,7 +866,7 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
 		struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
 
 		if (page_is_mergeable(bv, page, len, off, same_page)) {
-			if (bio->bi_iter.bi_size > bio_max_size(bio) - len) {
+			if (bio->bi_iter.bi_size > UINT_MAX - len) {
 				*same_page = false;
 				return false;
 			}
@@ -1002,7 +995,6 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 {
 	unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
 	unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
-	unsigned int bytes_left = bio_max_size(bio) - bio->bi_iter.bi_size;
 	struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
 	struct page **pages = (struct page **)bv;
 	bool same_page = false;
@@ -1018,8 +1010,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 	BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
 	pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
 
-	size = iov_iter_get_pages(iter, pages, bytes_left, nr_pages,
-				  &offset);
+	size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
 	if (unlikely(size <= 0))
 		return size ? size : -EFAULT;
 

block/blk-settings.c

@@ -31,7 +31,6 @@ EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
  */
 void blk_set_default_limits(struct queue_limits *lim)
 {
-	lim->bio_max_bytes = UINT_MAX;
 	lim->max_segments = BLK_MAX_SEGMENTS;
 	lim->max_discard_segments = 1;
 	lim->max_integrity_segments = 0;
@@ -140,10 +139,6 @@ void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_secto
 				 limits->logical_block_size >> SECTOR_SHIFT);
 	limits->max_sectors = max_sectors;
 
-	if (check_shl_overflow(max_sectors, SECTOR_SHIFT,
-				&limits->bio_max_bytes))
-		limits->bio_max_bytes = UINT_MAX;
-
 	q->backing_dev_info->io_pages = max_sectors >> (PAGE_SHIFT - 9);
 }
 EXPORT_SYMBOL(blk_queue_max_hw_sectors);

include/linux/bio.h

@@ -106,8 +106,6 @@ static inline void *bio_data(struct bio *bio)
 	return NULL;
 }
 
-extern unsigned int bio_max_size(struct bio *bio);
-
 /**
  * bio_full - check if the bio is full
  * @bio:	bio to check
@@ -121,7 +119,7 @@ static inline bool bio_full(struct bio *bio, unsigned len)
 	if (bio->bi_vcnt >= bio->bi_max_vecs)
 		return true;
 
-	if (bio->bi_iter.bi_size > bio_max_size(bio) - len)
+	if (bio->bi_iter.bi_size > UINT_MAX - len)
 		return true;
 
 	return false;

include/linux/blkdev.h

@@ -327,8 +327,6 @@ enum blk_bounce {
 };
 
 struct queue_limits {
-	unsigned int		bio_max_bytes;
-
 	enum blk_bounce		bounce;
 	unsigned long		seg_boundary_mask;
 	unsigned long		virt_boundary_mask;