linux-kernel - [PATCH 3/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_device

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Date:   Mon,  9 Apr 2018 23:04:12 +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 3/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_device_alloc

pcistub_device_alloc() is never called in atomic context.

The call chain ending up at pcistub_device_alloc() is:
[1] pcistub_device_alloc() <- pcistub_seize() <- pcistub_probe()
pcistub_probe() is only set as ".probe" in struct pci_driver.
This function is not called in atomic context.

Despite never getting called from atomic context,
pcistub_device_alloc() 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.

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..fecc536 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -71,7 +71,7 @@ static struct pcistub_device *pcistub_device_alloc(struct pci_dev *dev)

 	dev_dbg(&dev->dev, "pcistub_device_alloc\n");

-	psdev = kzalloc(sizeof(*psdev), GFP_ATOMIC);
+	psdev = kzalloc(sizeof(*psdev), GFP_KERNEL);
 	if (!psdev)
 		return NULL;

-- 
1.9.1