* [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device
@ 2018-03-18 14:53 ` Jia-Ju Bai
0 siblings, 0 replies; 7+ messages in thread
From: Jia-Ju Bai @ 2018-03-18 14:53 UTC (permalink / raw)
To: kys, haiyangz, sthemmin, bhelgaas
Cc: devel, Jia-Ju Bai, linux-kernel, linux-pci
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(-)
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
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device
@ 2018-03-18 14:53 ` Jia-Ju Bai
0 siblings, 0 replies; 7+ messages in thread
From: Jia-Ju Bai @ 2018-03-18 14:53 UTC (permalink / raw)
To: kys, haiyangz, sthemmin, bhelgaas
Cc: devel, linux-pci, linux-kernel, Jia-Ju Bai
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(-)
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
^ permalink raw reply related [flat|nested] 7+ messages in thread
* RE: [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device
2018-03-18 14:53 ` Jia-Ju Bai
@ 2018-03-18 22:42 ` Michael Kelley (EOSG)
-1 siblings, 0 replies; 7+ messages in thread
From: Michael Kelley (EOSG) @ 2018-03-18 22:42 UTC (permalink / raw)
To: Jia-Ju Bai, KY Srinivasan, Haiyang Zhang, Stephen Hemminger, bhelgaas
Cc: devel, linux-kernel, linux-pci
> -----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
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device
@ 2018-03-18 22:42 ` Michael Kelley (EOSG)
0 siblings, 0 replies; 7+ messages in thread
From: Michael Kelley (EOSG) @ 2018-03-18 22:42 UTC (permalink / raw)
To: Jia-Ju Bai, KY Srinivasan, Haiyang Zhang, Stephen Hemminger, bhelgaas
Cc: devel, linux-pci, linux-kernel
> -----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_K=
ERNEL in
> new_pcichild_device
>=20
> new_pcichild_device() is not called in atomic context.
>=20
> 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().
>=20
> 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.
>=20
> This is found by a static analysis tool named DCNS written by myself.
>=20
> 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(-)
>=20
> 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(struc=
t
> hv_pcibus_device *hbus,
> unsigned long flags;
> int ret;
>=20
> - hpdev =3D kzalloc(sizeof(*hpdev), GFP_ATOMIC);
> + hpdev =3D kzalloc(sizeof(*hpdev), GFP_KERNEL);
> if (!hpdev)
> return NULL;
>=20
> --
> 1.9.1
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device
2018-03-18 14:53 ` Jia-Ju Bai
@ 2018-03-19 8:46 ` Dan Carpenter
-1 siblings, 0 replies; 7+ messages in thread
From: Dan Carpenter @ 2018-03-19 8:46 UTC (permalink / raw)
To: Jia-Ju Bai; +Cc: sthemmin, linux-pci, haiyangz, linux-kernel, bhelgaas, devel
Looks ok.
regards,
dan carpenter
_______________________________________________
devel mailing list
devel@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device
@ 2018-03-19 8:46 ` Dan Carpenter
0 siblings, 0 replies; 7+ messages in thread
From: Dan Carpenter @ 2018-03-19 8:46 UTC (permalink / raw)
To: Jia-Ju Bai
Cc: kys, haiyangz, sthemmin, bhelgaas, devel, linux-kernel, linux-pci
Looks ok.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device
2018-03-18 14:53 ` Jia-Ju Bai
` (2 preceding siblings ...)
(?)
@ 2018-06-29 15:41 ` Lorenzo Pieralisi
-1 siblings, 0 replies; 7+ messages in thread
From: Lorenzo Pieralisi @ 2018-06-29 15:41 UTC (permalink / raw)
To: Jia-Ju Bai
Cc: kys, haiyangz, sthemmin, bhelgaas, devel, linux-pci, linux-kernel
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
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2018-06-29 15:39 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-03-18 14:53 [PATCH 2/2] pci: host: pci-hyperv: Replace GFP_ATOMIC with GFP_KERNEL in new_pcichild_device Jia-Ju Bai
2018-03-18 14:53 ` Jia-Ju Bai
2018-03-18 22:42 ` Michael Kelley (EOSG)
2018-03-18 22:42 ` Michael Kelley (EOSG)
2018-03-19 8:46 ` Dan Carpenter
2018-03-19 8:46 ` Dan Carpenter
2018-06-29 15:41 ` Lorenzo Pieralisi
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