linux-kernel - [PATCH 1/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub

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Date:   Mon,  9 Apr 2018 23:03:36 +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 1/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_probe

pcistub_probe() is never called in atomic context.
This function is only set as ".probe" in struct pci_driver.

Despite never getting called from atomic context,
pcistub_probe() calls kmalloc() 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..95e6ddd 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -577,7 +577,7 @@ static int pcistub_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		}

 		if (!match) {
-			pci_dev_id = kmalloc(sizeof(*pci_dev_id), GFP_ATOMIC);
+			pci_dev_id = kmalloc(sizeof(*pci_dev_id), GFP_KERNEL);
 			if (!pci_dev_id) {
 				err = -ENOMEM;
 				goto out;
-- 
1.9.1