From: "Mark A. Greer" <mgreer@animalcreek.com>
Subject: Re: [PATCH v3 1/2] omap-sham: Use pm_runtime_put instead of
 pm_runtime_put_sync in tasklet
Date: Tue, 26 Feb 2013 16:06:13 -0700
Message-ID: <20130226230613.GC13338@animalcreek.com>
References: <1361894672-10431-1-git-send-email-agnel.joel@gmail.com>
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Cc: linux-crypto@vger.kernel.org, Joel A Fernandes <joelagnel@ti.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>
To: agnel.joel@gmail.com
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In-Reply-To: <1361894672-10431-1-git-send-email-agnel.joel@gmail.com>
Sender: linux-crypto-owner@vger.kernel.org

On Tue, Feb 26, 2013 at 10:04:31AM -0600, agnel.joel@gmail.com wrote:
> From: Joel A Fernandes <joelagnel@ti.com>
> 
> After DMA is complete, the omap_sham_finish_req function is called as
> a part of the done_task tasklet. During this its atomic and any calls
> to pm functions should not assume they wont sleep.
> 
> The patch replaces a call to pm_runtime_put_sync (which can sleep) with
> pm_runtime_put thus fixing a kernel panic observed on AM33xx SoC during
> SHA operation.
> 
> Tested on an AM33xx SoC device (beaglebone board).
> To reproduce the problem, used the tcrypt kernel module as:
> modprobe tcrypt sec=2 mode=403
> 
> Signed-off-by: Joel A Fernandes <joelagnel@ti.com>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Mark A. Greer <mgreer@animalcreek.com>
> ---
>  drivers/crypto/omap-sham.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c
> index edff981..b8bb583 100644
> --- a/drivers/crypto/omap-sham.c
> +++ b/drivers/crypto/omap-sham.c
> @@ -923,7 +923,7 @@ static void omap_sham_finish_req(struct ahash_request *req, int err)
>  	dd->flags &= ~(BIT(FLAGS_BUSY) | BIT(FLAGS_FINAL) | BIT(FLAGS_CPU) |
>  			BIT(FLAGS_DMA_READY) | BIT(FLAGS_OUTPUT_READY));
>  
> -	pm_runtime_put_sync(dd->dev);
> +	pm_runtime_put(dd->dev);
>  
>  	if (req->base.complete)
>  		req->base.complete(&req->base, err);

Acked-by: Mark A. Greer <mgreer@animalcreek.com>