From fdbe4eeeb1aac219b14f10c0ed31ae5d1123e9b8 Mon Sep 17 00:00:00 2001
From: Alessio Balsini <balsini@android.com>
Date: Wed, 7 Aug 2019 01:48:28 +0100
Subject: [PATCH] loop: Add LOOP_SET_DIRECT_IO to compat ioctl
Git-commit: fdbe4eeeb1aac219b14f10c0ed31ae5d1123e9b8
Patch-mainline: v5.4-rc1
References: git-fixes

Enabling Direct I/O with loop devices helps reducing memory usage by
avoiding double caching.  32 bit applications running on 64 bits systems
are currently not able to request direct I/O because is missing from the
lo_compat_ioctl.

This patch fixes the compatibility issue mentioned above by exporting
LOOP_SET_DIRECT_IO as additional lo_compat_ioctl() entry.
The input argument for this ioctl is a single long converted to a 1-bit
boolean, so compatibility is preserved.

(Coly Li: rebased for Linux v4.12 based SUSE kernel)

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/block/loop.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1639,6 +1639,7 @@ static int lo_compat_ioctl(struct block_
 		arg = (unsigned long) compat_ptr(arg);
 	case LOOP_SET_FD:
 	case LOOP_CHANGE_FD:
+	case LOOP_SET_DIRECT_IO:
 		err = lo_ioctl(bdev, mode, cmd, arg);
 		break;
 	default: