scsi: Silence unnecessary warnings about ioctl to partition

commit 6d9359280753d2955f86d6411047516a9431eb51 upstream.

Sometimes, warnings about ioctls to partition happen often enough that they
form majority of the warnings in the kernel log and users complain. In some
cases warnings are about ioctls such as SG_IO so it's not good to get rid of
the warnings completely as they can ease debugging of userspace problems
when ioctl is refused.

Since I have seen warnings from lots of commands, including some proprietary
userspace applications, I don't think disallowing the ioctls for processes
with CAP_SYS_RAWIO will happen in the near future if ever. So lets just
stop warning for processes with CAP_SYS_RAWIO for which ioctl is allowed.

CC: Paolo Bonzini <pbonzini@redhat.com>
CC: James Bottomley <JBottomley@parallels.com>
CC: linux-scsi@vger.kernel.org
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[bwh: Backported to 3.2: use ENOTTY, not ENOIOCTLCMD]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 688be8a48b0d627d9fa7d04d7475f4c5b0ecba22..9e76a32740590307c4c515b1ec2e7573e698bd3c 100644 (file)
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -721,11 +721,14 @@ int scsi_verify_blk_ioctl(struct block_device *bd, unsigned int cmd)
                break;
        }
 
+       if (capable(CAP_SYS_RAWIO))
+               return 0;
+
        /* In particular, rule out all resets and host-specific ioctls.  */
        printk_ratelimited(KERN_WARNING
                           "%s: sending ioctl %x to a partition!\n", current->comm, cmd);
 
-       return capable(CAP_SYS_RAWIO) ? 0 : -ENOTTY;
+       return -ENOTTY;
 }
 EXPORT_SYMBOL(scsi_verify_blk_ioctl);