2018-04-09 15:09:51

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH 4/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in xen_pcibk_config_quirks_init

xen_pcibk_config_quirks_init() is never called in atomic context.

The call chains ending up at xen_pcibk_config_quirks_init() are:
[1] xen_pcibk_config_quirks_init() <- xen_pcibk_config_init_dev() <-
pcistub_init_device() <- pcistub_seize() <- pcistub_probe()
[2] xen_pcibk_config_quirks_init() <- xen_pcibk_config_init_dev() <-
pcistub_init_device() <- pcistub_init_devices_late() <-
xen_pcibk_init()
pcistub_probe() is only set as ".probe" in struct pci_driver.
xen_pcibk_init() is is only set as a parameter of module_init().
These functions are not called in atomic context.

Despite never getting called from atomic context,
xen_pcibk_config_quirks_init() 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 <[email protected]>
---
drivers/xen/xen-pciback/conf_space_quirks.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/xen-pciback/conf_space_quirks.c b/drivers/xen/xen-pciback/conf_space_quirks.c
index 7476791..e3df3f9 100644
--- a/drivers/xen/xen-pciback/conf_space_quirks.c
+++ b/drivers/xen/xen-pciback/conf_space_quirks.c
@@ -94,7 +94,7 @@ int xen_pcibk_config_quirks_init(struct pci_dev *dev)
struct xen_pcibk_config_quirk *quirk;
int ret = 0;

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