Re: [PATCH net-next v6 4/4] eventpoll: Add epoll ioctl for epoll_params

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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@xxxxxxxxxx>
...
--- 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@xxxxxxxxxx>

+		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





[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [NTFS 3]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [NTFS 3]     [Samba]     [Device Mapper]     [CEPH Development]

  Powered by Linux