[PATCH] drivers/block/loop.c: don't return garbage if LOOP_SET_STATUS not called

While writing a version of losetup, I ran into the problem that the loop
device was returning total garbage.

It turns out the problem was that this losetup was only issuing the
LOOP_SET_FD ioctl and not issuing a subsequent LOOP_SET_STATUS ioctl.  This
losetup didn't have any special status to set, so it left out the call.

The deeper cause is that loop_set_fd sets the transfer function to NULL,
which causes no transfer to happen lo_do_transfer.

This patch fixes the problem by setting transfer to transfer_none in
loop_set_fd.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 9c3b94e8f03baa7d4138802e01b87e27e511c159..3c74ea729fc79529ed766b98f3e1d2b78bb3da57 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -818,7 +818,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
        lo->lo_device = bdev;
        lo->lo_flags = lo_flags;
        lo->lo_backing_file = file;
-       lo->transfer = NULL;
+       lo->transfer = transfer_none;
        lo->ioctl = NULL;
        lo->lo_sizelimit = 0;
        lo->old_gfp_mask = mapping_gfp_mask(mapping);