[patch] x86/AMD: remove an unneeded condition in srat_detect_node()

[patch] x86/AMD: remove an unneeded condition in srat_detect_node()

[Dan Carpenter]

Originally we calculated ht_nodeid as "ht_nodeid = apicid - boot_cpu_id;"
so presumably it could be negative.  But after commit 01aaea1afbcd
('x86: introduce initial apicid') we use c->initial_apicid which is an
unsigned short and thus always >= 0.

It causes a static checker warning to test for impossible conditions so
let's remove it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index e678dde..a07956a 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -434,8 +434,7 @@ static void srat_detect_node(struct cpuinfo_x86 *c)
 		 */
 		int ht_nodeid = c->initial_apicid;
 
-		if (ht_nodeid >= 0 &&
-		    __apicid_to_node[ht_nodeid] != NUMA_NO_NODE)
+		if (__apicid_to_node[ht_nodeid] != NUMA_NO_NODE)
 			node = __apicid_to_node[ht_nodeid];
 		/* Pick a nearby node */
 		if (!node_online(node))

Re: [patch] x86/AMD: remove an unneeded condition in srat_detect_node()

[Huang Rui]

On Wed, Jan 13, 2016 at 03:39:40PM +0300, Dan Carpenter wrote:
> Originally we calculated ht_nodeid as "ht_nodeid = apicid - boot_cpu_id;"
> so presumably it could be negative.  But after commit 01aaea1afbcd
> ('x86: introduce initial apicid') we use c->initial_apicid which is an
> unsigned short and thus always >= 0.
> 
> It causes a static checker warning to test for impossible conditions so
> let's remove it.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 

Looks OK for me.

Reviewed-by: Huang Rui <ray.huang@amd.com>

> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> index e678dde..a07956a 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -434,8 +434,7 @@ static void srat_detect_node(struct cpuinfo_x86 *c)
>  		 */
>  		int ht_nodeid = c->initial_apicid;
>  
> -		if (ht_nodeid >= 0 &&
> -		    __apicid_to_node[ht_nodeid] != NUMA_NO_NODE)
> +		if (__apicid_to_node[ht_nodeid] != NUMA_NO_NODE)
>  			node = __apicid_to_node[ht_nodeid];
>  		/* Pick a nearby node */
>  		if (!node_online(node))

[tip:x86/urgent] x86/cpu/amd: Remove an unneeded condition in srat_detect_node()

[tip-bot for Dan Carpenter]

Commit-ID:  7030a7e9321166eef44c811fe4af4d460360d424
Gitweb:     http://git.kernel.org/tip/7030a7e9321166eef44c811fe4af4d460360d424
Author:     Dan Carpenter <dan.carpenter@oracle.com>
AuthorDate: Wed, 13 Jan 2016 15:39:40 +0300
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 14 Jan 2016 09:46:00 +0100

x86/cpu/amd: Remove an unneeded condition in srat_detect_node()

Originally we calculated ht_nodeid as "ht_nodeid = apicid -
boot_cpu_id;" so presumably it could be negative.

But after commit:

  01aaea1afbcd ('x86: introduce initial apicid')

we use c->initial_apicid which is an unsigned short and thus always >= 0.

It causes a static checker warning to test for impossible
conditions so let's remove it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Hector Marco-Gisbert <hecmargi@upv.es>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Link: http://lkml.kernel.org/r/20160113123940.GE19993@mwanda
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/cpu/amd.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index e678dde..a07956a 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -434,8 +434,7 @@ static void srat_detect_node(struct cpuinfo_x86 *c)
 		 */
 		int ht_nodeid = c->initial_apicid;
 
-		if (ht_nodeid >= 0 &&
-		    __apicid_to_node[ht_nodeid] != NUMA_NO_NODE)
+		if (__apicid_to_node[ht_nodeid] != NUMA_NO_NODE)
 			node = __apicid_to_node[ht_nodeid];
 		/* Pick a nearby node */
 		if (!node_online(node))