6.14-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
[ Upstream commit 355341e4359b2d5edf0ed5e117f7e9e7a0a5dac0 ]
Block devices can be opened read-write even if they can't be written to for historic reasons. Remove the check requiring file->f_op->write_iter when the block devices was opened in loop_configure. The call to loop_check_backing_file just below ensures the ->write_iter is present for backing files opened for writing, which is the only check that is actually needed.
Fixes: f5c84eff634b ("loop: Add sanity check for read/write_iter") Reported-by: Christian Hesse mail@eworm.de Signed-off-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20250520135420.1177312-1-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/loop.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index f68f86e9cb716..0b135d1ca25ea 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -973,9 +973,6 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode, if (!file) return -EBADF;
- if ((mode & BLK_OPEN_WRITE) && !file->f_op->write_iter) - return -EINVAL; - error = loop_check_backing_file(file); if (error) return error;