From: Alessio Balsini <balsini@android.com>
To: gregkh@linuxfoundation.org
Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@android.com, Jens Axboe <axboe@kernel.dk>,
Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH 4.4 4.9 4.14] loop: Add LOOP_SET_DIRECT_IO to compat ioctl
Date: Wed, 23 Oct 2019 18:22:44 +0100 [thread overview]
Message-ID: <20191023172244.GA164146@google.com> (raw)
In-Reply-To: <20191023171736.161697-1-balsini@android.com>
Ops, please forgive the wrong in-reply-to messge id :)
Cheers,
Alessio
On Wed, Oct 23, 2019 at 06:17:36PM +0100, Alessio Balsini wrote:
> [ 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 da3902ac16c86..8aadd4d0c3a88 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1557,6 +1557,7 @@ 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:
> --
> 2.23.0.866.gb869b98d4c-goog
>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com.
>
next prev parent reply other threads:[~2019-10-23 17:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190805115309.GJ2349@hirez.programming.kicks-ass.net>
2019-10-23 17:17 ` [PATCH 4.4 4.9 4.14] loop: Add LOOP_SET_DIRECT_IO to compat ioctl Alessio Balsini
2019-10-23 17:22 ` Alessio Balsini [this message]
2019-10-25 0:17 ` Sasha Levin
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