linux-block.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Alessio Balsini <balsini@android.com>
To: linux-block@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk, dvander@gmail.com,
	elsk@google.com, gregkh@linuxfoundation.org, joelaf@google.com,
	kernel-team@android.com
Subject: [PATCH v2] loop: Add LOOP_SET_DIRECT_IO to compat ioctl
Date: Wed,  7 Aug 2019 01:48:28 +0100	[thread overview]
Message-ID: <20190807004828.28059-1-balsini@android.com> (raw)
In-Reply-To: <CAJWu+oo=GrZ+SbA6=bboM4==TKXBsTRWkTrkWiZ55pqhJtgQqQ@mail.gmail.com>

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

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 44c9985f352ab..2e2193f754ab0 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1753,6 +1753,7 @@ 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:
-- 
2.23.0.rc1.153.gdeed80330f-goog


  reply	other threads:[~2019-08-07  0:50 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-06 22:05 [PATCH] loop: Add LOOP_SET_DIRECT_IO in compat ioctl Alessio Balsini
2019-08-06 22:25 ` Joel Fernandes
2019-08-06 23:57   ` Alessio Balsini
2019-08-07  0:10     ` Joel Fernandes
2019-08-07  0:48       ` Alessio Balsini [this message]
2019-08-08 23:51         ` [PATCH v2] loop: Add LOOP_SET_DIRECT_IO to " Joel Fernandes
2019-08-09  3:39         ` Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190807004828.28059-1-balsini@android.com \
    --to=balsini@android.com \
    --cc=axboe@kernel.dk \
    --cc=dvander@gmail.com \
    --cc=elsk@google.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=joelaf@google.com \
    --cc=kernel-team@android.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).