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From: Wei Yang <richard.weiyang@linux.alibaba.com>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: david@redhat.com, akpm@linux-foundation.org, ardb@kernel.org,
	bhe@redhat.com, jgg@ziepe.ca, keescook@chromium.org,
	linux-acpi@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-nvdimm@lists.01.org, linux-s390@vger.kernel.org,
	mhocko@suse.com, pankaj.gupta.linux@gmail.com,
	virtualization@lists.linux-foundation.org,
	xen-devel@lists.xenproject.org,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH] kernel/resource: Fix use of ternary condition in release_mem_region_adjustable
Date: Fri, 9 Oct 2020 17:24:33 +0800	[thread overview]
Message-ID: <20201009092433.GA56924@L-31X9LVDL-1304.local> (raw)
In-Reply-To: <20200922060748.2452056-1-natechancellor@gmail.com>

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

-- 
Wei Yang
Help you, Help me
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  parent reply	other threads:[~2020-10-09  9:24 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-11 10:34 [PATCH v4 0/8] selective merging of system ram resources David Hildenbrand
2020-09-11 10:34 ` [PATCH v4 1/8] kernel/resource: make release_mem_region_adjustable() never fail David Hildenbrand
2020-09-22  6:07   ` [PATCH] kernel/resource: Fix use of ternary condition in release_mem_region_adjustable Nathan Chancellor
2020-09-22  6:22     ` David Hildenbrand
2020-10-09  9:24     ` Wei Yang [this message]
2020-09-11 10:34 ` [PATCH v4 2/8] kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED David Hildenbrand
2020-09-11 10:34 ` [PATCH v4 3/8] mm/memory_hotplug: guard more declarations by CONFIG_MEMORY_HOTPLUG David Hildenbrand
2020-09-11 10:34 ` [PATCH v4 4/8] mm/memory_hotplug: prepare passing flags to add_memory() and friends David Hildenbrand
2020-09-11 10:34 ` [PATCH v4 5/8] mm/memory_hotplug: MEMHP_MERGE_RESOURCE to specify merging of System RAM resources David Hildenbrand
2020-09-15  2:43   ` Wei Yang
2020-09-15  7:25     ` David Hildenbrand
2020-09-16 12:51   ` Wei Yang
2020-09-11 10:34 ` [PATCH v4 6/8] virtio-mem: try to merge system ram resources David Hildenbrand
2020-09-16 12:52   ` Wei Yang
2020-09-11 10:34 ` [PATCH v4 7/8] xen/balloon: " David Hildenbrand
2020-09-16 12:52   ` Wei Yang
2020-09-11 10:34 ` [PATCH v4 8/8] hv_balloon: " David Hildenbrand
2020-09-16 12:52   ` Wei Yang
2020-09-16  7:30 ` [PATCH] kernel/resource: make iomem_resource implicit in release_mem_region_adjustable() David Hildenbrand
2020-09-16 10:02   ` Wei Yang
2020-09-16 10:03     ` David Hildenbrand
2020-09-16 12:10       ` Wei Yang
2020-09-16 12:16         ` David Hildenbrand
2020-09-16 12:40           ` Wei Yang
2020-09-17  8:38   ` Pankaj Gupta

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