Add an ioctl for getting and setting epoll_params. User programs can use
this ioctl to get and set the busy poll usec time or packet budget
params for a specific epoll context.
Signed-off-by: Joe Damato <jdamato@fastly.com>
---
.../userspace-api/ioctl/ioctl-number.rst | 1 +
fs/eventpoll.c | 47 +++++++++++++++++++
include/uapi/linux/eventpoll.h | 12 +++++
3 files changed, 60 insertions(+)
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 457e16f06e04..b33918232f78 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -309,6 +309,7 @@ Code Seq# Include File Comments
0x89 0B-DF linux/sockios.h
0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
+0x8A 00-1F linux/eventpoll.h
0x8B all linux/wireless.h
0x8C 00-3F WiNRADiO driver
<http://www.winradio.com.au/>
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 40bd97477b91..c1ee0fe01da1 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -6,6 +6,8 @@
* Davide Libenzi <davidel@xmailserver.org>
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
@@ -869,6 +871,49 @@ static void ep_clear_and_put(struct eventpoll *ep)
ep_free(ep);
}
+static long ep_eventpoll_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ int ret;
+ struct eventpoll *ep;
+ struct epoll_params epoll_params;
+ void __user *uarg = (void __user *) arg;
+
+ if (!is_file_epoll(file))
+ return -EINVAL;
+
+ ep = file->private_data;
+
+ switch (cmd) {
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ case EPIOCSPARAMS:
+ if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params)))
+ return -EFAULT;
+
+ if (epoll_params.busy_poll_budget > NAPI_POLL_WEIGHT)
+ pr_err("busy poll budget %u exceeds suggested maximum %u\n",
+ epoll_params.busy_poll_budget, NAPI_POLL_WEIGHT);
+
+ ep->busy_poll_usecs = epoll_params.busy_poll_usecs;
+ ep->busy_poll_budget = epoll_params.busy_poll_budget;
+ return 0;
+
+ case EPIOCGPARAMS:
+ memset(&epoll_params, 0, sizeof(epoll_params));
+ epoll_params.busy_poll_usecs = ep->busy_poll_usecs;
+ epoll_params.busy_poll_budget = ep->busy_poll_budget;
+ if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params)))
+ return -EFAULT;
+
+ return 0;
+#endif
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
static int ep_eventpoll_release(struct inode *inode, struct file *file)
{
struct eventpoll *ep = file->private_data;
@@ -975,6 +1020,8 @@ static const struct file_operations eventpoll_fops = {
.release = ep_eventpoll_release,
.poll = ep_eventpoll_poll,
.llseek = noop_llseek,
+ .unlocked_ioctl = ep_eventpoll_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
};
/*
diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h
index cfbcc4cc49ac..8eb0fdbce995 100644
--- a/include/uapi/linux/eventpoll.h
+++ b/include/uapi/linux/eventpoll.h
@@ -85,4 +85,16 @@ struct epoll_event {
__u64 data;
} EPOLL_PACKED;
+struct epoll_params {
+ u64 busy_poll_usecs;
+ u16 busy_poll_budget;
+
+ /* for future fields */
+ u8 data[118];
+} EPOLL_PACKED;
+
+#define EPOLL_IOC_TYPE 0x8A
+#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params)
+#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params)
+
#endif /* _UAPI_LINUX_EVENTPOLL_H */
--
2.25.1Hi Joe,
kernel test robot noticed the following build warnings:
[auto build test WARNING on net-next/main]
url: https://github.com/intel-lab-lkp/linux/commits/Joe-Damato/eventpoll-support-busy-poll-per-epoll-instance/20240125-083418
base: net-next/main
patch link: https://lore.kernel.org/r/20240125003014.43103-4-jdamato%40fastly.com
patch subject: [net-next v2 3/4] eventpoll: Add epoll ioctl for epoll_params
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20240125/202401252141.eUlgsF08-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240125/202401252141.eUlgsF08-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401252141.eUlgsF08-lkp@intel.com/
All warnings (new ones prefixed by >>):
fs/eventpoll.c: In function 'ep_eventpoll_ioctl':
>> fs/eventpoll.c:879:22: warning: unused variable 'uarg' [-Wunused-variable]
879 | void __user *uarg = (void __user *) arg;
| ^~~~
>> fs/eventpoll.c:878:29: warning: unused variable 'epoll_params' [-Wunused-variable]
878 | struct epoll_params epoll_params;
| ^~~~~~~~~~~~
fs/eventpoll.c:877:27: warning: variable 'ep' set but not used [-Wunused-but-set-variable]
877 | struct eventpoll *ep;
| ^~
vim +/uarg +879 fs/eventpoll.c
873
874 static long ep_eventpoll_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
875 {
876 int ret;
877 struct eventpoll *ep;
> 878 struct epoll_params epoll_params;
> 879 void __user *uarg = (void __user *) arg;
880
881 if (!is_file_epoll(file))
882 return -EINVAL;
883
884 ep = file->private_data;
885
886 switch (cmd) {
887 #ifdef CONFIG_NET_RX_BUSY_POLL
888 case EPIOCSPARAMS:
889 if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params)))
890 return -EFAULT;
891
892 if (epoll_params.busy_poll_budget > NAPI_POLL_WEIGHT)
893 pr_err("busy poll budget %u exceeds suggested maximum %u\n",
894 epoll_params.busy_poll_budget, NAPI_POLL_WEIGHT);
895
896 ep->busy_poll_usecs = epoll_params.busy_poll_usecs;
897 ep->busy_poll_budget = epoll_params.busy_poll_budget;
898 return 0;
899
900 case EPIOCGPARAMS:
901 memset(&epoll_params, 0, sizeof(epoll_params));
902 epoll_params.busy_poll_usecs = ep->busy_poll_usecs;
903 epoll_params.busy_poll_budget = ep->busy_poll_budget;
904 if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params)))
905 return -EFAULT;
906
907 return 0;
908 #endif
909 default:
910 ret = -EINVAL;
911 break;
912 }
913
914 return ret;
915 }
916
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Joe Damato wrote:
> Add an ioctl for getting and setting epoll_params. User programs can use
> this ioctl to get and set the busy poll usec time or packet budget
> params for a specific epoll context.
>
> Signed-off-by: Joe Damato <jdamato@fastly.com>
Please be sure to include the lists and people suggested by
`get_maintainer.pl -f fs/eventpoll.c`.
Adding ioctls is generally discouraged.
As this affects the behavior of epoll_wait, should this just be a
flag to (a new variant of) epoll_wait?
Speaking from some experience with adding epoll_pwait2. I initially
there added a stateful change that would affect wait behavior. The
sensible feedback as the time was to just change the behavior of the
syscall it affected. Even if that requires a syscall (which is not
that different from an ioctl, if better defined).
The discussion in that thread may be informative to decide on API:
https://lwn.net/ml/linux-kernel/20201116161001.1606608-1-willemdebruijn.kernel@gmail.com/
Agreed on the overall principle that it is preferable to be able to
enable busypolling selectively. We already do for SO_BUSY_POLL and
sysctl busy_read.
> ---
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> fs/eventpoll.c | 47 +++++++++++++++++++
> include/uapi/linux/eventpoll.h | 12 +++++
> 3 files changed, 60 insertions(+)
>
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index 457e16f06e04..b33918232f78 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -309,6 +309,7 @@ Code Seq# Include File Comments
> 0x89 0B-DF linux/sockios.h
> 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
> 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
> +0x8A 00-1F linux/eventpoll.h
> 0x8B all linux/wireless.h
> 0x8C 00-3F WiNRADiO driver
> <http://www.winradio.com.au/>
> diff --git a/fs/eventpoll.c b/fs/eventpoll.c
> index 40bd97477b91..c1ee0fe01da1 100644
> --- a/fs/eventpoll.c
> +++ b/fs/eventpoll.c
> @@ -6,6 +6,8 @@
> * Davide Libenzi <davidel@xmailserver.org>
> */
>
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> #include <linux/init.h>
> #include <linux/kernel.h>
> #include <linux/sched/signal.h>
> @@ -869,6 +871,49 @@ static void ep_clear_and_put(struct eventpoll *ep)
> ep_free(ep);
> }
>
> +static long ep_eventpoll_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> + int ret;
> + struct eventpoll *ep;
> + struct epoll_params epoll_params;
> + void __user *uarg = (void __user *) arg;
> +
> + if (!is_file_epoll(file))
> + return -EINVAL;
> +
> + ep = file->private_data;
> +
> + switch (cmd) {
> +#ifdef CONFIG_NET_RX_BUSY_POLL
> + case EPIOCSPARAMS:
> + if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params)))
> + return -EFAULT;
> +
> + if (epoll_params.busy_poll_budget > NAPI_POLL_WEIGHT)
> + pr_err("busy poll budget %u exceeds suggested maximum %u\n",
> + epoll_params.busy_poll_budget, NAPI_POLL_WEIGHT);
> +
> + ep->busy_poll_usecs = epoll_params.busy_poll_usecs;
> + ep->busy_poll_budget = epoll_params.busy_poll_budget;
> + return 0;
> +
> + case EPIOCGPARAMS:
> + memset(&epoll_params, 0, sizeof(epoll_params));
> + epoll_params.busy_poll_usecs = ep->busy_poll_usecs;
> + epoll_params.busy_poll_budget = ep->busy_poll_budget;
> + if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params)))
> + return -EFAULT;
> +
> + return 0;
> +#endif
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> + return ret;
> +}
> +
> static int ep_eventpoll_release(struct inode *inode, struct file *file)
> {
> struct eventpoll *ep = file->private_data;
> @@ -975,6 +1020,8 @@ static const struct file_operations eventpoll_fops = {
> .release = ep_eventpoll_release,
> .poll = ep_eventpoll_poll,
> .llseek = noop_llseek,
> + .unlocked_ioctl = ep_eventpoll_ioctl,
> + .compat_ioctl = compat_ptr_ioctl,
> };
>
> /*
> diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h
> index cfbcc4cc49ac..8eb0fdbce995 100644
> --- a/include/uapi/linux/eventpoll.h
> +++ b/include/uapi/linux/eventpoll.h
> @@ -85,4 +85,16 @@ struct epoll_event {
> __u64 data;
> } EPOLL_PACKED;
>
> +struct epoll_params {
> + u64 busy_poll_usecs;
> + u16 busy_poll_budget;
> +
> + /* for future fields */
> + u8 data[118];
> +} EPOLL_PACKED;
> +
> +#define EPOLL_IOC_TYPE 0x8A
> +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params)
> +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params)
> +
> #endif /* _UAPI_LINUX_EVENTPOLL_H */
> --
> 2.25.1
>
On Wed, Jan 24, 2024 at 09:46:23PM -0500, Willem de Bruijn wrote:
> Joe Damato wrote:
> > Add an ioctl for getting and setting epoll_params. User programs can use
> > this ioctl to get and set the busy poll usec time or packet budget
> > params for a specific epoll context.
> >
> > Signed-off-by: Joe Damato <jdamato@fastly.com>
>
> Please be sure to include the lists and people suggested by
> `get_maintainer.pl -f fs/eventpoll.c`.
Thanks - I must have done something wrong when trying to get the maintainer
list.
Should I resend this v2? Not sure what the appropriate thing to do is in
this case. My apologies.
> Adding ioctls is generally discouraged.
>
> As this affects the behavior of epoll_wait, should this just be a
> flag to (a new variant of) epoll_wait?
I have no strong preference either way. It seems to me that adding a new
system call is a fairly significant change vs adding an ioctl, but I am
open to whatever is preferred by the maintainers.
I have no idea who would need to weigh-in to make this decision.
> Speaking from some experience with adding epoll_pwait2. I initially
> there added a stateful change that would affect wait behavior. The
> sensible feedback as the time was to just change the behavior of the
> syscall it affected. Even if that requires a syscall (which is not
> that different from an ioctl, if better defined).
>
> The discussion in that thread may be informative to decide on API:
> https://lwn.net/ml/linux-kernel/20201116161001.1606608-1-willemdebruijn.kernel@gmail.com/
Interesting thread, thanks for sending.
> Agreed on the overall principle that it is preferable to be able to
> enable busypolling selectively. We already do for SO_BUSY_POLL and
> sysctl busy_read.
Thanks for taking a look and providing feedback.
>
> > ---
> > .../userspace-api/ioctl/ioctl-number.rst | 1 +
> > fs/eventpoll.c | 47 +++++++++++++++++++
> > include/uapi/linux/eventpoll.h | 12 +++++
> > 3 files changed, 60 insertions(+)
> >
> > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > index 457e16f06e04..b33918232f78 100644
> > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > @@ -309,6 +309,7 @@ Code Seq# Include File Comments
> > 0x89 0B-DF linux/sockios.h
> > 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
> > 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
> > +0x8A 00-1F linux/eventpoll.h
> > 0x8B all linux/wireless.h
> > 0x8C 00-3F WiNRADiO driver
> > <http://www.winradio.com.au/>
> > diff --git a/fs/eventpoll.c b/fs/eventpoll.c
> > index 40bd97477b91..c1ee0fe01da1 100644
> > --- a/fs/eventpoll.c
> > +++ b/fs/eventpoll.c
> > @@ -6,6 +6,8 @@
> > * Davide Libenzi <davidel@xmailserver.org>
> > */
> >
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> > #include <linux/init.h>
> > #include <linux/kernel.h>
> > #include <linux/sched/signal.h>
> > @@ -869,6 +871,49 @@ static void ep_clear_and_put(struct eventpoll *ep)
> > ep_free(ep);
> > }
> >
> > +static long ep_eventpoll_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> > +{
> > + int ret;
> > + struct eventpoll *ep;
> > + struct epoll_params epoll_params;
> > + void __user *uarg = (void __user *) arg;
> > +
> > + if (!is_file_epoll(file))
> > + return -EINVAL;
> > +
> > + ep = file->private_data;
> > +
> > + switch (cmd) {
> > +#ifdef CONFIG_NET_RX_BUSY_POLL
> > + case EPIOCSPARAMS:
> > + if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params)))
> > + return -EFAULT;
> > +
> > + if (epoll_params.busy_poll_budget > NAPI_POLL_WEIGHT)
> > + pr_err("busy poll budget %u exceeds suggested maximum %u\n",
> > + epoll_params.busy_poll_budget, NAPI_POLL_WEIGHT);
> > +
> > + ep->busy_poll_usecs = epoll_params.busy_poll_usecs;
> > + ep->busy_poll_budget = epoll_params.busy_poll_budget;
> > + return 0;
> > +
> > + case EPIOCGPARAMS:
> > + memset(&epoll_params, 0, sizeof(epoll_params));
> > + epoll_params.busy_poll_usecs = ep->busy_poll_usecs;
> > + epoll_params.busy_poll_budget = ep->busy_poll_budget;
> > + if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params)))
> > + return -EFAULT;
> > +
> > + return 0;
> > +#endif
> > + default:
> > + ret = -EINVAL;
> > + break;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > static int ep_eventpoll_release(struct inode *inode, struct file *file)
> > {
> > struct eventpoll *ep = file->private_data;
> > @@ -975,6 +1020,8 @@ static const struct file_operations eventpoll_fops = {
> > .release = ep_eventpoll_release,
> > .poll = ep_eventpoll_poll,
> > .llseek = noop_llseek,
> > + .unlocked_ioctl = ep_eventpoll_ioctl,
> > + .compat_ioctl = compat_ptr_ioctl,
> > };
> >
> > /*
> > diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h
> > index cfbcc4cc49ac..8eb0fdbce995 100644
> > --- a/include/uapi/linux/eventpoll.h
> > +++ b/include/uapi/linux/eventpoll.h
> > @@ -85,4 +85,16 @@ struct epoll_event {
> > __u64 data;
> > } EPOLL_PACKED;
> >
> > +struct epoll_params {
> > + u64 busy_poll_usecs;
> > + u16 busy_poll_budget;
> > +
> > + /* for future fields */
> > + u8 data[118];
> > +} EPOLL_PACKED;
> > +
> > +#define EPOLL_IOC_TYPE 0x8A
> > +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params)
> > +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params)
> > +
> > #endif /* _UAPI_LINUX_EVENTPOLL_H */
> > --
> > 2.25.1
> >
>
>
Joe Damato wrote:
> On Wed, Jan 24, 2024 at 09:46:23PM -0500, Willem de Bruijn wrote:
> > Joe Damato wrote:
> > > Add an ioctl for getting and setting epoll_params. User programs can use
> > > this ioctl to get and set the busy poll usec time or packet budget
> > > params for a specific epoll context.
> > >
> > > Signed-off-by: Joe Damato <jdamato@fastly.com>
> >
> > Please be sure to include the lists and people suggested by
> > `get_maintainer.pl -f fs/eventpoll.c`.
>
> Thanks - I must have done something wrong when trying to get the maintainer
> list.
>
> Should I resend this v2? Not sure what the appropriate thing to do is in
> this case. My apologies.
If you don't get additional feedback in a few days and still prefer
this option that might be an approach.
After reading the below thread, compare the different possible APIs
and either revise the code or perhaps add a small paragraph why you
think this is the preferred path.
> > Adding ioctls is generally discouraged.
> >
> > As this affects the behavior of epoll_wait, should this just be a
> > flag to (a new variant of) epoll_wait?
>
> I have no strong preference either way. It seems to me that adding a new
> system call is a fairly significant change vs adding an ioctl, but I am
> open to whatever is preferred by the maintainers.
>
> I have no idea who would need to weigh-in to make this decision.
>
> > Speaking from some experience with adding epoll_pwait2. I initially
> > there added a stateful change that would affect wait behavior. The
> > sensible feedback as the time was to just change the behavior of the
> > syscall it affected. Even if that requires a syscall (which is not
> > that different from an ioctl, if better defined).
> >
> > The discussion in that thread may be informative to decide on API:
> > https://lwn.net/ml/linux-kernel/20201116161001.1606608-1-willemdebruijn.kernel@gmail.com/
>
> Interesting thread, thanks for sending.
>
> > Agreed on the overall principle that it is preferable to be able to
> > enable busypolling selectively. We already do for SO_BUSY_POLL and
> > sysctl busy_read.
>
> Thanks for taking a look and providing feedback.
>
> >
> > > ---
> > > .../userspace-api/ioctl/ioctl-number.rst | 1 +
> > > fs/eventpoll.c | 47 +++++++++++++++++++
> > > include/uapi/linux/eventpoll.h | 12 +++++
> > > 3 files changed, 60 insertions(+)
> > >
> > > diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > > index 457e16f06e04..b33918232f78 100644
> > > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> > > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > > @@ -309,6 +309,7 @@ Code Seq# Include File Comments
> > > 0x89 0B-DF linux/sockios.h
> > > 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
> > > 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
> > > +0x8A 00-1F linux/eventpoll.h
> > > 0x8B all linux/wireless.h
> > > 0x8C 00-3F WiNRADiO driver
> > > <http://www.winradio.com.au/>
> > > diff --git a/fs/eventpoll.c b/fs/eventpoll.c
> > > index 40bd97477b91..c1ee0fe01da1 100644
> > > --- a/fs/eventpoll.c
> > > +++ b/fs/eventpoll.c
> > > @@ -6,6 +6,8 @@
> > > * Davide Libenzi <davidel@xmailserver.org>
> > > */
> > >
> > > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > > +
> > > #include <linux/init.h>
> > > #include <linux/kernel.h>
> > > #include <linux/sched/signal.h>
> > > @@ -869,6 +871,49 @@ static void ep_clear_and_put(struct eventpoll *ep)
> > > ep_free(ep);
> > > }
> > >
> > > +static long ep_eventpoll_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> > > +{
> > > + int ret;
> > > + struct eventpoll *ep;
> > > + struct epoll_params epoll_params;
> > > + void __user *uarg = (void __user *) arg;
> > > +
> > > + if (!is_file_epoll(file))
> > > + return -EINVAL;
> > > +
> > > + ep = file->private_data;
> > > +
> > > + switch (cmd) {
> > > +#ifdef CONFIG_NET_RX_BUSY_POLL
> > > + case EPIOCSPARAMS:
> > > + if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params)))
> > > + return -EFAULT;
> > > +
> > > + if (epoll_params.busy_poll_budget > NAPI_POLL_WEIGHT)
> > > + pr_err("busy poll budget %u exceeds suggested maximum %u\n",
> > > + epoll_params.busy_poll_budget, NAPI_POLL_WEIGHT);
> > > +
> > > + ep->busy_poll_usecs = epoll_params.busy_poll_usecs;
> > > + ep->busy_poll_budget = epoll_params.busy_poll_budget;
> > > + return 0;
> > > +
> > > + case EPIOCGPARAMS:
> > > + memset(&epoll_params, 0, sizeof(epoll_params));
> > > + epoll_params.busy_poll_usecs = ep->busy_poll_usecs;
> > > + epoll_params.busy_poll_budget = ep->busy_poll_budget;
> > > + if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params)))
> > > + return -EFAULT;
> > > +
> > > + return 0;
> > > +#endif
> > > + default:
> > > + ret = -EINVAL;
> > > + break;
> > > + }
> > > +
> > > + return ret;
> > > +}
> > > +
> > > static int ep_eventpoll_release(struct inode *inode, struct file *file)
> > > {
> > > struct eventpoll *ep = file->private_data;
> > > @@ -975,6 +1020,8 @@ static const struct file_operations eventpoll_fops = {
> > > .release = ep_eventpoll_release,
> > > .poll = ep_eventpoll_poll,
> > > .llseek = noop_llseek,
> > > + .unlocked_ioctl = ep_eventpoll_ioctl,
> > > + .compat_ioctl = compat_ptr_ioctl,
> > > };
> > >
> > > /*
> > > diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h
> > > index cfbcc4cc49ac..8eb0fdbce995 100644
> > > --- a/include/uapi/linux/eventpoll.h
> > > +++ b/include/uapi/linux/eventpoll.h
> > > @@ -85,4 +85,16 @@ struct epoll_event {
> > > __u64 data;
> > > } EPOLL_PACKED;
> > >
> > > +struct epoll_params {
> > > + u64 busy_poll_usecs;
> > > + u16 busy_poll_budget;
> > > +
> > > + /* for future fields */
> > > + u8 data[118];
> > > +} EPOLL_PACKED;
> > > +
> > > +#define EPOLL_IOC_TYPE 0x8A
> > > +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params)
> > > +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params)
> > > +
> > > #endif /* _UAPI_LINUX_EVENTPOLL_H */
> > > --
> > > 2.25.1
> > >
> >
> >
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