From: Robin Holt <holt@sgi.com>
To: Julia Lawall <julia@diku.dk>
Cc: Robin Holt <holt@sgi.com>,
kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] drivers/misc/sgi-xp/xpc_uv.c: convert nested
Date: Wed, 20 Oct 2010 02:51:31 +0000 [thread overview]
Message-ID: <20101020025130.GE14068@sgi.com> (raw)
In-Reply-To: <1287481436-26656-4-git-send-email-julia@diku.dk>
On Tue, Oct 19, 2010 at 11:43:56AM +0200, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
>
> If spin_lock_irqsave is called twice in a row with the same second
> argument, the interrupt state at the point of the second call overwrites
> the value saved by the first call. Indeed, the second call does not need
> to save the interrupt state, so it is changed to a simple spin_lock.
>
> The semantic match that finds this problem is as follows:
> (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @@
> expression lock1,lock2;
> expression flags;
> @@
>
> *spin_lock_irqsave(lock1,flags)
> ... when != flags
> *spin_lock_irqsave(lock2,flags)
> // </smpl>
>
> Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Robin Holt <holt@sgi.com>
>
> ---
> drivers/misc/sgi-xp/xpc_uv.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c
> index 1f59ee2..7aeaef7 100644
> --- a/drivers/misc/sgi-xp/xpc_uv.c
> +++ b/drivers/misc/sgi-xp/xpc_uv.c
> @@ -451,9 +451,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
>
> if (msg->activate_gru_mq_desc_gpa !> part_uv->activate_gru_mq_desc_gpa) {
> - spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
> + spin_lock(&part_uv->flags_lock);
> part_uv->flags &= ~XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV;
> - spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
> + spin_unlock(&part_uv->flags_lock);
> part_uv->activate_gru_mq_desc_gpa > msg->activate_gru_mq_desc_gpa;
> }
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: Julia Lawall <julia@diku.dk>
Cc: Robin Holt <holt@sgi.com>,
kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] drivers/misc/sgi-xp/xpc_uv.c: convert nested spin_lock_irqsave to spin_lock
Date: Tue, 19 Oct 2010 21:51:31 -0500 [thread overview]
Message-ID: <20101020025130.GE14068@sgi.com> (raw)
In-Reply-To: <1287481436-26656-4-git-send-email-julia@diku.dk>
On Tue, Oct 19, 2010 at 11:43:56AM +0200, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
>
> If spin_lock_irqsave is called twice in a row with the same second
> argument, the interrupt state at the point of the second call overwrites
> the value saved by the first call. Indeed, the second call does not need
> to save the interrupt state, so it is changed to a simple spin_lock.
>
> The semantic match that finds this problem is as follows:
> (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @@
> expression lock1,lock2;
> expression flags;
> @@
>
> *spin_lock_irqsave(lock1,flags)
> ... when != flags
> *spin_lock_irqsave(lock2,flags)
> // </smpl>
>
> Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Robin Holt <holt@sgi.com>
>
> ---
> drivers/misc/sgi-xp/xpc_uv.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c
> index 1f59ee2..7aeaef7 100644
> --- a/drivers/misc/sgi-xp/xpc_uv.c
> +++ b/drivers/misc/sgi-xp/xpc_uv.c
> @@ -451,9 +451,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
>
> if (msg->activate_gru_mq_desc_gpa !=
> part_uv->activate_gru_mq_desc_gpa) {
> - spin_lock_irqsave(&part_uv->flags_lock, irq_flags);
> + spin_lock(&part_uv->flags_lock);
> part_uv->flags &= ~XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV;
> - spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags);
> + spin_unlock(&part_uv->flags_lock);
> part_uv->activate_gru_mq_desc_gpa =
> msg->activate_gru_mq_desc_gpa;
> }
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
next prev parent reply other threads:[~2010-10-20 2:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-19 9:43 [PATCH 4/4] drivers/misc/sgi-xp/xpc_uv.c: convert nested spin_lock_irqsave to spin_lock Julia Lawall
2010-10-19 9:43 ` Julia Lawall
2010-10-20 2:51 ` Robin Holt [this message]
2010-10-20 2:51 ` Robin Holt
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