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authorLinus Torvalds <torvalds@linux-foundation.org>2012-01-05 15:40:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-05 15:40:12 -0800
commit07d106d0a33d6063d2061305903deb02489eba20 (patch)
tree6f257f877a9c2e653ca0515253e930fa6606239a /block
parent805a6af8dba5dfdd35ec35dc52ec0122400b2610 (diff)
downloadlinux-linaro-stable-07d106d0a33d6063d2061305903deb02489eba20.tar.gz
vfs: fix up ENOIOCTLCMD error handling
We're doing some odd things there, which already messes up various users (see the net/socket.c code that this removes), and it was going to add yet more crud to the block layer because of the incorrect error code translation. ENOIOCTLCMD is not an error return that should be returned to user mode from the "ioctl()" system call, but it should *not* be translated as EINVAL ("Invalid argument"). It should be translated as ENOTTY ("Inappropriate ioctl for device"). That EINVAL confusion has apparently so permeated some code that the block layer actually checks for it, which is sad. We continue to do so for now, but add a big comment about how wrong that is, and we should remove it entirely eventually. In the meantime, this tries to keep the changes localized to just the EINVAL -> ENOTTY fix, and removing code that makes it harder to do the right thing. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'block')
-rw-r--r--block/ioctl.c26
1 files changed, 22 insertions, 4 deletions
diff --git a/block/ioctl.c b/block/ioctl.c
index ca939fc1030f..d510c2a4eff8 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -180,6 +180,26 @@ int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
/*
+ * Is it an unrecognized ioctl? The correct returns are either
+ * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
+ * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
+ * code before returning.
+ *
+ * Confused drivers sometimes return EINVAL, which is wrong. It
+ * means "I understood the ioctl command, but the parameters to
+ * it were wrong".
+ *
+ * We should aim to just fix the broken drivers, the EINVAL case
+ * should go away.
+ */
+static inline int is_unrecognized_ioctl(int ret)
+{
+ return ret == -EINVAL ||
+ ret == -ENOTTY ||
+ ret == -ENOIOCTLCMD;
+}
+
+/*
* always keep this in sync with compat_blkdev_ioctl()
*/
int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
@@ -196,8 +216,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
return -EACCES;
ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
- /* -EINVAL to handle old uncorrected drivers */
- if (ret != -EINVAL && ret != -ENOTTY)
+ if (!is_unrecognized_ioctl(ret))
return ret;
fsync_bdev(bdev);
@@ -206,8 +225,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
case BLKROSET:
ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
- /* -EINVAL to handle old uncorrected drivers */
- if (ret != -EINVAL && ret != -ENOTTY)
+ if (!is_unrecognized_ioctl(ret))
return ret;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;