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From: Tim Chen <tim.c.chen@linux.intel.com>
To: "H. Peter Anvin" <hpa@zytor.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, Megha Dey <megha.dey@intel.com>,
	"Wang, Rui Y" <rui.y.wang@intel.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Xiaodong Liu <xiaodong.liu@intel.com>,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [patch] crypto: sha256-mb - cleanup a || vs | typo
Date: Thu, 30 Jun 2016 13:42:19 -0700	[thread overview]
Message-ID: <1467319339.22178.256.camel@linux.intel.com> (raw)
In-Reply-To: <8538242a-eab7-127e-e47e-26027fee4f6d@zytor.com>

On Wed, 2016-06-29 at 10:05 -0700, H. Peter Anvin wrote:
> On 06/29/16 07:42, Dan Carpenter wrote:
> > 
> > > 
> > > > 
> > > > and | behave basically the same here but || is intended.  It causes a
> > static checker warning to mix up bitwise and logical operations.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > diff --git a/arch/x86/crypto/sha256-mb/sha256_mb.c b/arch/x86/crypto/sha256-mb/sha256_mb.c
> > index c9d5dcc..4ec895a 100644
> > --- a/arch/x86/crypto/sha256-mb/sha256_mb.c
> > +++ b/arch/x86/crypto/sha256-mb/sha256_mb.c
> > @@ -299,7 +299,7 @@ static struct sha256_hash_ctx *sha256_ctx_mgr_submit(struct sha256_ctx_mgr *mgr,
> >  	 * Or if the user's buffer contains less than a whole block,
> >  	 * append as much as possible to the extra block.
> >  	 */
> > -	if ((ctx->partial_block_buffer_length) | (len < SHA256_BLOCK_SIZE)) {
> > +	if ((ctx->partial_block_buffer_length) || (len < SHA256_BLOCK_SIZE)) {
> >  		/* Compute how many bytes to copy from user buffer into
> >  		 * extra block
> >  		 */
> > 
> As far as I know the | was an intentional optimization, so you may way
> to look at the generated code.
> 
> 	-hpa
> 

Yes, this is an intentional optimization.  Is there any scenario where things may
break with the compiler?

Tim

  parent reply	other threads:[~2016-06-30 20:42 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-29 14:42 [patch] crypto: sha256-mb - cleanup a || vs | typo Dan Carpenter
2016-06-29 17:05 ` H. Peter Anvin
2016-06-30  7:50   ` Dan Carpenter
2016-06-30 11:16     ` Joe Perches
2016-06-30 11:45       ` walter harms
2016-06-30 12:33         ` Dan Carpenter
2016-06-30 20:42   ` Tim Chen [this message]
2016-06-30 22:16     ` Dan Carpenter
2016-07-01  7:55     ` Ingo Molnar
2016-07-01  9:28       ` Herbert Xu
2016-07-01 10:13         ` Ingo Molnar
2016-07-08 16:28           ` Tim Chen
2016-07-08 16:45             ` Herbert Xu
2016-07-08 17:17               ` Tim Chen
2016-07-08 17:19               ` Linus Torvalds
2016-07-11  6:40                 ` Geert Uytterhoeven
2016-07-18  8:59                 ` Pavel Machek
2016-07-18 22:12                   ` Tim Chen
2016-07-11 10:09             ` Herbert Xu

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