diff mbox series

kernel/resource: Fix use of ternary condition in release_mem_region_adjustable

Message ID 20200922060748.2452056-1-natechancellor@gmail.com (mailing list archive)
State New
Headers show
Series kernel/resource: Fix use of ternary condition in release_mem_region_adjustable | expand

Commit Message

Nathan Chancellor Sept. 22, 2020, 6:07 a.m. UTC
Clang warns:

kernel/resource.c:1281:53: warning: operator '?:' has lower precedence
than '|'; '|' will be evaluated first
[-Wbitwise-conditional-parentheses]
        new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
kernel/resource.c:1281:53: note: place parentheses around the '|'
expression to silence this warning
        new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
kernel/resource.c:1281:53: note: place parentheses around the '?:'
expression to evaluate it first
        new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
                                                           ^
                                              (                              )
1 warning generated.

Add the parentheses as it was clearly intended for the ternary condition
to be evaluated first.

Fixes: 5fd23bd0d739 ("kernel/resource: make release_mem_region_adjustable() never fail")
Link: https://github.com/ClangBuiltLinux/linux/issues/1159
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

Presumably, this will be squashed but I included a fixes tag
nonetheless. Apologies if this has already been noticed and fixed
already, I did not find anything on LKML.

 kernel/resource.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


base-commit: 40ee82f47bf297e31d0c47547cd8f24ede52415a

Comments

David Hildenbrand Sept. 22, 2020, 6:22 a.m. UTC | #1
On 22.09.20 08:07, Nathan Chancellor wrote:
> Clang warns:
> 
> kernel/resource.c:1281:53: warning: operator '?:' has lower precedence
> than '|'; '|' will be evaluated first
> [-Wbitwise-conditional-parentheses]
>         new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
>                                  ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
> kernel/resource.c:1281:53: note: place parentheses around the '|'
> expression to silence this warning
>         new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
>                                  ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
> kernel/resource.c:1281:53: note: place parentheses around the '?:'
> expression to evaluate it first
>         new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
>                                                            ^
>                                               (                              )
> 1 warning generated.
> 
> Add the parentheses as it was clearly intended for the ternary condition
> to be evaluated first.
> 
> Fixes: 5fd23bd0d739 ("kernel/resource: make release_mem_region_adjustable() never fail")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1159
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> 
> Presumably, this will be squashed but I included a fixes tag
> nonetheless. Apologies if this has already been noticed and fixed
> already, I did not find anything on LKML.

Hasn't been noticed before (I guess most people build with GCC, which
does not warn in this instance, at least for me) thanks!

Commit ids are not stable yet, so Andrew will most probably squash it.

Reviewed-by: David Hildenbrand <david@redhat.com>

> 
>  kernel/resource.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/resource.c b/kernel/resource.c
> index ca2a666e4317..3ae2f56cc79d 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -1278,7 +1278,7 @@ void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
>  	 * similarly).
>  	 */
>  retry:
> -	new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
> +	new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
>  
>  	p = &parent->child;
>  	write_lock(&resource_lock);
> 
> base-commit: 40ee82f47bf297e31d0c47547cd8f24ede52415a
>
Wei Yang Oct. 9, 2020, 9:24 a.m. UTC | #2
On Mon, Sep 21, 2020 at 11:07:48PM -0700, Nathan Chancellor wrote:
>Clang warns:
>
>kernel/resource.c:1281:53: warning: operator '?:' has lower precedence
>than '|'; '|' will be evaluated first
>[-Wbitwise-conditional-parentheses]
>        new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
>                                 ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
>kernel/resource.c:1281:53: note: place parentheses around the '|'
>expression to silence this warning
>        new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
>                                 ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
>kernel/resource.c:1281:53: note: place parentheses around the '?:'
>expression to evaluate it first
>        new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
>                                                           ^
>                                              (                              )
>1 warning generated.
>
>Add the parentheses as it was clearly intended for the ternary condition
>to be evaluated first.
>
>Fixes: 5fd23bd0d739 ("kernel/resource: make release_mem_region_adjustable() never fail")
>Link: https://github.com/ClangBuiltLinux/linux/issues/1159
>Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>

>---
>
>Presumably, this will be squashed but I included a fixes tag
>nonetheless. Apologies if this has already been noticed and fixed
>already, I did not find anything on LKML.
>
> kernel/resource.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/kernel/resource.c b/kernel/resource.c
>index ca2a666e4317..3ae2f56cc79d 100644
>--- a/kernel/resource.c
>+++ b/kernel/resource.c
>@@ -1278,7 +1278,7 @@ void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
> 	 * similarly).
> 	 */
> retry:
>-	new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
>+	new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
> 
> 	p = &parent->child;
> 	write_lock(&resource_lock);
>
>base-commit: 40ee82f47bf297e31d0c47547cd8f24ede52415a
>-- 
>2.28.0
diff mbox series

Patch

diff --git a/kernel/resource.c b/kernel/resource.c
index ca2a666e4317..3ae2f56cc79d 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1278,7 +1278,7 @@  void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
 	 * similarly).
 	 */
 retry:
-	new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0);
+	new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
 
 	p = &parent->child;
 	write_lock(&resource_lock);