Re: [PATCH net-next v6 4/4] eventpoll: Add epoll ioctl for epoll_params
From: Jiri Slaby <jirislaby@kernel.org>
Date: 2024-02-07 08:37:19
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On 05. 02. 24, 22:04, 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, 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 <redacted>...
quoted hunk ↗ jump to hunk
--- a/fs/eventpoll.c +++ b/fs/eventpoll.c
...
quoted hunk ↗ jump to hunk
@@ -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;
This might have been on the ep declaration line.
+ 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;This !! is unnecessary. Nonzero values shall be "converted" to true. But FWIW, the above is nothing which should be blocking, so: Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
+ 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; + } +}
... thanks, -- js suse labs