linux-kernel - [PATCH] x86: efi: Replace GFP_ATOMIC with GFP_KERNEL in efi_query_variable

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Date:   Thu, 25 Jan 2018 10:29:46 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     matt@...eblueprint.co.uk, ard.biesheuvel@...aro.org,
        tglx@...utronix.de, mingo@...hat.com, hpa@...or.com
Cc:     x86@...nel.org, linux-efi@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] x86: efi: Replace GFP_ATOMIC with GFP_KERNEL in efi_query_variable_store

The function kzalloc here is not called in atomic context.
If nonblocking in efi_query_variable_store is true, 
namely it is in atomic context, efi_query_variable_store will return before
this kzalloc is called.
Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 arch/x86/platform/efi/quirks.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 8a99a2e..b6dcb52 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -177,7 +177,7 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
 		 * that by attempting to use more space than is available.
 		 */
 		unsigned long dummy_size = remaining_size + 1024;
-		void *dummy = kzalloc(dummy_size, GFP_ATOMIC);
+		void *dummy = kzalloc(dummy_size, GFP_KERNEL);
 
 		if (!dummy)
 			return EFI_OUT_OF_RESOURCES;
-- 
1.7.9.5