Commit fdbe4eee authored Aug 07, 2019 by Alessio Balsini Committed by Jens Axboe Aug 08, 2019

loop: Add LOOP_SET_DIRECT_IO to compat ioctl



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>

parent 79e178f4

drivers/block/loop.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1755,6 +1755,7 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
		case LOOP_SET_FD:
		case LOOP_CHANGE_FD:
		case LOOP_SET_BLOCK_SIZE:
		case LOOP_SET_DIRECT_IO:
		err = lo_ioctl(bdev, mode, cmd, arg);
		break;
		default:

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