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Subject[PATCH 4.14 028/119] loop: Add LOOP_SET_DIRECT_IO to compat ioctl
Date
From: Alessio Balsini <balsini@android.com>

[ Upstream commit fdbe4eeeb1aac219b14f10c0ed31ae5d1123e9b8 ]

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.

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: Sasha Levin <sashal@kernel.org>
---
drivers/block/loop.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 87d7c42affbc4..ec61dd873c93d 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1605,6 +1605,7 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
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:
--
2.20.1


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