From: Joe Damato <jdamato@fastly.com>
To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc: chuck.lever@oracle.com, jlayton@kernel.org,
linux-api@vger.kernel.org, brauner@kernel.org,
edumazet@google.com, davem@davemloft.net,
alexander.duyck@gmail.com, sridhar.samudrala@intel.com,
kuba@kernel.org, willemdebruijn.kernel@gmail.com,
weiwan@google.com, David.Laight@ACULAB.COM, arnd@arndb.de,
sdf@google.com, amritha.nambiar@intel.com,
Joe Damato <jdamato@fastly.com>, Jonathan Corbet <corbet@lwn.net>,
Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
Nathan Lynch <nathanl@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Namjae Jeon <linkinjeon@kernel.org>,
Steve French <stfrench@microsoft.com>,
Thomas Zimmermann <tzimmermann@suse.de>,
Jiri Slaby <jirislaby@kernel.org>,
Julien Panis <jpanis@baylibre.com>,
Andrew Waterman <waterman@eecs.berkeley.edu>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-doc@vger.kernel.org (open list:DOCUMENTATION),
linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and
infrastructure))
Subject: [PATCH net-next v6 4/4] eventpoll: Add epoll ioctl for epoll_params
Date: Mon, 5 Feb 2024 21:04:49 +0000 [thread overview]
Message-ID: <20240205210453.11301-5-jdamato@fastly.com> (raw)
In-Reply-To: <20240205210453.11301-1-jdamato@fastly.com>
Add an ioctl for getting and setting epoll_params. User programs can use
this ioctl to get and set the busy poll usec time, packet budget, and
prefer busy poll params for a specific epoll context.
Parameters are limited:
- busy_poll_usecs is limited to <= u32_max
- busy_poll_budget is limited to <= NAPI_POLL_WEIGHT by unprivileged
users (!capable(CAP_NET_ADMIN))
- prefer_busy_poll must be 0 or 1
- __pad must be 0
Signed-off-by: Joe Damato <jdamato@fastly.com>
---
.../userspace-api/ioctl/ioctl-number.rst | 1 +
fs/eventpoll.c | 73 +++++++++++++++++++
include/uapi/linux/eventpoll.h | 13 ++++
3 files changed, 87 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 a69ee11682b9..8eb4ea2557af 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -37,6 +37,7 @@
#include <linux/seq_file.h>
#include <linux/compat.h>
#include <linux/rculist.h>
+#include <linux/capability.h>
#include <net/busy_poll.h>
/*
@@ -497,6 +498,50 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
ep->napi_id = napi_id;
}
+static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct eventpoll *ep;
+ struct epoll_params epoll_params;
+ void __user *uarg = (void __user *) arg;
+
+ ep = file->private_data;
+
+ switch (cmd) {
+ case EPIOCSPARAMS:
+ if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params)))
+ return -EFAULT;
+
+ if (memchr_inv(epoll_params.__pad, 0, sizeof(epoll_params.__pad)))
+ return -EINVAL;
+
+ if (epoll_params.busy_poll_usecs > U32_MAX)
+ return -EINVAL;
+
+ if (epoll_params.prefer_busy_poll > 1)
+ return -EINVAL;
+
+ if (epoll_params.busy_poll_budget > NAPI_POLL_WEIGHT &&
+ !capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ ep->busy_poll_usecs = epoll_params.busy_poll_usecs;
+ ep->busy_poll_budget = epoll_params.busy_poll_budget;
+ ep->prefer_busy_poll = !!epoll_params.prefer_busy_poll;
+ 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;
+ epoll_params.prefer_busy_poll = ep->prefer_busy_poll;
+ if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params)))
+ return -EFAULT;
+ return 0;
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
#else
static inline bool ep_busy_loop(struct eventpoll *ep, int nonblock)
@@ -512,6 +557,12 @@ static inline bool ep_busy_loop_on(struct eventpoll *ep)
{
return false;
}
+
+static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_NET_RX_BUSY_POLL */
/*
@@ -871,6 +922,26 @@ 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;
+
+ if (!is_file_epoll(file))
+ return -EINVAL;
+
+ switch (cmd) {
+ case EPIOCSPARAMS:
+ case EPIOCGPARAMS:
+ ret = ep_eventpoll_bp_ioctl(file, cmd, arg);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
static int ep_eventpoll_release(struct inode *inode, struct file *file)
{
struct eventpoll *ep = file->private_data;
@@ -977,6 +1048,8 @@ 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..36a002660955 100644
--- a/include/uapi/linux/eventpoll.h
+++ b/include/uapi/linux/eventpoll.h
@@ -85,4 +85,17 @@ struct epoll_event {
__u64 data;
} EPOLL_PACKED;
+struct epoll_params {
+ __aligned_u64 busy_poll_usecs;
+ __u16 busy_poll_budget;
+ __u8 prefer_busy_poll;
+
+ /* pad the struct to a multiple of 64bits for alignment on all arches */
+ __u8 __pad[5];
+};
+
+#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
next prev parent reply other threads:[~2024-02-05 21:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-05 21:04 [PATCH net-next v6 0/4] Per epoll context busy poll support Joe Damato
2024-02-05 21:04 ` [PATCH net-next v6 1/4] eventpoll: support busy poll per epoll instance Joe Damato
2024-02-07 19:04 ` Jakub Kicinski
2024-02-07 19:14 ` Joe Damato
2024-02-07 20:11 ` Jakub Kicinski
2024-02-07 20:23 ` Joe Damato
2024-02-07 20:56 ` Jakub Kicinski
2024-02-08 17:46 ` Eric Dumazet
2024-02-08 18:06 ` Joe Damato
2024-02-05 21:04 ` [PATCH net-next v6 2/4] eventpoll: Add per-epoll busy poll packet budget Joe Damato
2024-02-07 19:04 ` Jakub Kicinski
2024-02-08 17:47 ` Eric Dumazet
2024-02-05 21:04 ` [PATCH net-next v6 3/4] eventpoll: Add per-epoll prefer busy poll option Joe Damato
2024-02-07 19:04 ` Jakub Kicinski
2024-02-08 17:49 ` Eric Dumazet
2024-02-05 21:04 ` Joe Damato [this message]
2024-02-07 8:37 ` [PATCH net-next v6 4/4] eventpoll: Add epoll ioctl for epoll_params Jiri Slaby
2024-02-07 18:50 ` Joe Damato
2024-02-07 19:07 ` Jakub Kicinski
2024-02-07 19:16 ` Joe Damato
2024-02-07 20:18 ` Jakub Kicinski
2024-02-06 18:51 ` [PATCH net-next v6 0/4] Per epoll context busy poll support Stanislav Fomichev
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