From bdd44337d5822fab04d53658c511630ca1c05fa0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 20 May 2025 15:54:20 +0200 Subject: [PATCH] UPSTREAM: loop: don't require ->write_iter for writable files in loop_configure [ 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 Change-Id: Ie3d17da68cb81076f5841f83901a37753f8e10ee Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250520135420.1177312-1-hch@lst.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin (cherry picked from commit cd7f022296972daf35b750c3fa71a6bc9ebc0abf) Signed-off-by: Greg Kroah-Hartman --- drivers/block/loop.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 6398fd2c18a8..a4bec161b32b 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -976,9 +976,6 @@ 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;