linux-kernel - [PATCH, RFC 28/30] sgi-xp: open-code interruptible_sleep_on

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1388664474-1710039-29-git-send-email-arnd@arndb.de>
Date:	Thu,  2 Jan 2014 13:07:52 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	linux-kernel@...r.kernel.org
Cc:	Arnd Bergmann <arnd@...db.de>, Cliff Whickman <cpw@....com>,
	Robin Holt <robinmholt@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH, RFC 28/30] sgi-xp: open-code interruptible_sleep_on_timeout

interruptible_sleep_on_timeout is deprecated and going away soon.
The use in the sgi-xp driver leaves me puzzled, so I'd prefer not
to touch it. This patch replaces it with an open-coded prepare_to_wait
and finish_wait pair, which should be completely equivalent, so it
doesn't fix an existing race, but lets us get away with removing
the function so we can not get any new users.

In order to remove the typical sleep_on race, one would have to
replace the call with wait_event_interruptible_timeout and add
a condition to wait for. The fact that there is a one-jiffy timeout
suggests that we don't actually expect to get woken up properly
and the caller just uses this as a short sleeping function
if it doesn't wake up properly.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Cc: Cliff Whickman <cpw@....com>
Cc: Robin Holt <robinmholt@...il.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/misc/sgi-xp/xpc_channel.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/sgi-xp/xpc_channel.c b/drivers/misc/sgi-xp/xpc_channel.c
index 652593f..128d561 100644
--- a/drivers/misc/sgi-xp/xpc_channel.c
+++ b/drivers/misc/sgi-xp/xpc_channel.c
@@ -828,6 +828,7 @@ enum xp_retval
 xpc_allocate_msg_wait(struct xpc_channel *ch)
 {
 	enum xp_retval ret;
+	DEFINE_WAIT(wait);
 
 	if (ch->flags & XPC_C_DISCONNECTING) {
 		DBUG_ON(ch->reason == xpInterrupted);
@@ -835,7 +836,9 @@ xpc_allocate_msg_wait(struct xpc_channel *ch)
 	}
 
 	atomic_inc(&ch->n_on_msg_allocate_wq);
-	ret = interruptible_sleep_on_timeout(&ch->msg_allocate_wq, 1);
+	prepare_to_wait(&ch->msg_allocate_wq, &wait, TASK_INTERRUPTIBLE);
+	ret = schedule_timeout(1);
+	finish_wait(&ch->msg_allocate_wq, &wait);
 	atomic_dec(&ch->n_on_msg_allocate_wq);
 
 	if (ch->flags & XPC_C_DISCONNECTING) {
-- 
1.8.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/