Messages in this thread | | | Date | Wed, 7 Feb 2024 09:37:14 +0100 | Subject | Re: [PATCH net-next v6 4/4] eventpoll: Add epoll ioctl for epoll_params | From | Jiri Slaby <> |
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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 <jdamato@fastly.com> .. > --- a/fs/eventpoll.c > +++ b/fs/eventpoll.c .. > @@ -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
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