linux-kernel - [PATCH] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_reg

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Date:   Wed, 11 Apr 2018 09:15:31 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     boris.ostrovsky@...cle.com, jgross@...e.com,
        gregkh@...uxfoundation.org
Cc:     xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_reg_add

pcistub_reg_add() is never called in atomic context.

pcistub_reg_add() is only called by pcistub_quirk_add, which is 
only set in DRIVER_ATTR().

Despite never getting called from atomic context,
pcistub_reg_add() calls kzalloc() with GFP_ATOMIC,
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
which can sleep and improve the possibility of sucessful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 drivers/xen/xen-pciback/pci_stub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index 9e480fd..9d92bed 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -1149,7 +1149,7 @@ static int pcistub_reg_add(int domain, int bus, int slot, int func,
 	}
 	dev = psdev->dev;

-	field = kzalloc(sizeof(*field), GFP_ATOMIC);
+	field = kzalloc(sizeof(*field), GFP_KERNEL);
 	if (!field) {
 		err = -ENOMEM;
 		goto out;
-- 
1.9.1