| Message ID | 1521384808-23627-1-git-send-email-baijiaju1990@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | Lorenzo Pieralisi |
| Headers | show |
| Series | [1/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in hv_pci_onchannelcallback | expand |
> -----Original Message----- > From: linux-kernel-owner@vger.kernel.org <linux-kernel-owner@vger.kernel.org> On Behalf > Of Jia-Ju Bai > Sent: Sunday, March 18, 2018 7:53 AM > To: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.com>; Stephen > Hemminger <sthemmin@microsoft.com>; bhelgaas@google.com > Cc: devel@linuxdriverproject.org; linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; > Jia-Ju Bai <baijiaju1990@gmail.com> > Subject: [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in > new_pcichild_device > > new_pcichild_device() is not called in atomic context. > > The call chain ending up at new_pcichild_device() is: > [1] new_pcichild_device() <- pci_devices_present_work() > pci_devices_present_work() is only set in INIT_WORK(). > > Despite never getting called from atomic context, > new_pcichild_device() calls kzalloc with GFP_ATOMIC, > which waits busily for allocation. > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL > to avoid busy waiting. > > This is found by a static analysis tool named DCNS written by myself. > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> > --- > drivers/pci/host/pci-hyperv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c > index 0fe3ea1..289e31d 100644 > --- a/drivers/pci/host/pci-hyperv.c > +++ b/drivers/pci/host/pci-hyperv.c > @@ -1500,7 +1500,7 @@ static struct hv_pci_dev *new_pcichild_device(struct > hv_pcibus_device *hbus, > unsigned long flags; > int ret; > > - hpdev = kzalloc(sizeof(*hpdev), GFP_ATOMIC); > + hpdev = kzalloc(sizeof(*hpdev), GFP_KERNEL); > if (!hpdev) > return NULL; > > -- > 1.9.1
Looks ok. regards, dan carpenter
On Sun, Mar 18, 2018 at 10:53:28PM +0800, Jia-Ju Bai wrote: > new_pcichild_device() is not called in atomic context. > > The call chain ending up at new_pcichild_device() is: > [1] new_pcichild_device() <- pci_devices_present_work() > pci_devices_present_work() is only set in INIT_WORK(). > > Despite never getting called from atomic context, > new_pcichild_device() calls kzalloc with GFP_ATOMIC, > which waits busily for allocation. > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL > to avoid busy waiting. > > This is found by a static analysis tool named DCNS written by myself. > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> > --- > drivers/pci/host/pci-hyperv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Applied to pci/hv for v4.19, thanks. Lorenzo > diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c > index 0fe3ea1..289e31d 100644 > --- a/drivers/pci/host/pci-hyperv.c > +++ b/drivers/pci/host/pci-hyperv.c > @@ -1500,7 +1500,7 @@ static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus, > unsigned long flags; > int ret; > > - hpdev = kzalloc(sizeof(*hpdev), GFP_ATOMIC); > + hpdev = kzalloc(sizeof(*hpdev), GFP_KERNEL); > if (!hpdev) > return NULL; > > -- > 1.9.1 >
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 0fe3ea1..289e31d 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1500,7 +1500,7 @@ static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus, unsigned long flags; int ret; - hpdev = kzalloc(sizeof(*hpdev), GFP_ATOMIC); + hpdev = kzalloc(sizeof(*hpdev), GFP_KERNEL); if (!hpdev) return NULL;
new_pcichild_device() is not called in atomic context. The call chain ending up at new_pcichild_device() is: [1] new_pcichild_device() <- pci_devices_present_work() pci_devices_present_work() is only set in INIT_WORK(). Despite never getting called from atomic context, new_pcichild_device() calls kzalloc with GFP_ATOMIC, which waits busily for allocation. GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL to avoid busy waiting. This is found by a static analysis tool named DCNS written by myself. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- drivers/pci/host/pci-hyperv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)