diff options
Diffstat (limited to 'fs/eventpoll.c')
| -rw-r--r-- | fs/eventpoll.c | 147 |
1 files changed, 129 insertions, 18 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 3534d36a1474..882b89edc52a 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> /* @@ -206,7 +207,7 @@ struct eventpoll { */ struct epitem *ovflist; - /* wakeup_source used when ep_scan_ready_list is running */ + /* wakeup_source used when ep_send_events or __ep_eventpoll_poll is running */ struct wakeup_source *ws; /* The user that created the eventpoll descriptor */ @@ -227,6 +228,11 @@ struct eventpoll { #ifdef CONFIG_NET_RX_BUSY_POLL /* used to track busy poll napi_id */ unsigned int napi_id; + /* busy poll timeout */ + u32 busy_poll_usecs; + /* busy poll packet budget */ + u16 busy_poll_budget; + bool prefer_busy_poll; #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -387,11 +393,41 @@ static inline int ep_events_available(struct eventpoll *ep) } #ifdef CONFIG_NET_RX_BUSY_POLL +/** + * busy_loop_ep_timeout - check if busy poll has timed out. The timeout value + * from the epoll instance ep is preferred, but if it is not set fallback to + * the system-wide global via busy_loop_timeout. + * + * @start_time: The start time used to compute the remaining time until timeout. + * @ep: Pointer to the eventpoll context. + * + * Return: true if the timeout has expired, false otherwise. + */ +static bool busy_loop_ep_timeout(unsigned long start_time, + struct eventpoll *ep) +{ + unsigned long bp_usec = READ_ONCE(ep->busy_poll_usecs); + + if (bp_usec) { + unsigned long end_time = start_time + bp_usec; + unsigned long now = busy_loop_current_time(); + + return time_after(now, end_time); + } else { + return busy_loop_timeout(start_time); + } +} + +static bool ep_busy_loop_on(struct eventpoll *ep) +{ + return !!ep->busy_poll_usecs || net_busy_loop_on(); +} + static bool ep_busy_loop_end(void *p, unsigned long start_time) { struct eventpoll *ep = p; - return ep_events_available(ep) || busy_loop_timeout(start_time); + return ep_events_available(ep) || busy_loop_ep_timeout(start_time, ep); } /* @@ -403,10 +439,15 @@ static bool ep_busy_loop_end(void *p, unsigned long start_time) static bool ep_busy_loop(struct eventpoll *ep, int nonblock) { unsigned int napi_id = READ_ONCE(ep->napi_id); + u16 budget = READ_ONCE(ep->busy_poll_budget); + bool prefer_busy_poll = READ_ONCE(ep->prefer_busy_poll); - if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on()) { - napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep, false, - BUSY_POLL_BUDGET); + if (!budget) + budget = BUSY_POLL_BUDGET; + + if (napi_id >= MIN_NAPI_ID && ep_busy_loop_on(ep)) { + napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, + ep, prefer_busy_poll, budget); if (ep_events_available(ep)) return true; /* @@ -425,12 +466,12 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonblock) */ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { - struct eventpoll *ep; + struct eventpoll *ep = epi->ep; unsigned int napi_id; struct socket *sock; struct sock *sk; - if (!net_busy_loop_on()) + if (!ep_busy_loop_on(ep)) return; sock = sock_from_file(epi->ffd.file); @@ -442,7 +483,6 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) return; napi_id = READ_ONCE(sk->sk_napi_id); - ep = epi->ep; /* Non-NAPI IDs can be rejected * or @@ -455,6 +495,49 @@ 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 = file->private_data; + void __user *uarg = (void __user *)arg; + struct epoll_params epoll_params; + + switch (cmd) { + case EPIOCSPARAMS: + if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params))) + return -EFAULT; + + /* pad byte must be zero */ + if (epoll_params.__pad) + return -EINVAL; + + if (epoll_params.busy_poll_usecs > S32_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; + + WRITE_ONCE(ep->busy_poll_usecs, epoll_params.busy_poll_usecs); + WRITE_ONCE(ep->busy_poll_budget, epoll_params.busy_poll_budget); + WRITE_ONCE(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 = READ_ONCE(ep->busy_poll_usecs); + epoll_params.busy_poll_budget = READ_ONCE(ep->busy_poll_budget); + epoll_params.prefer_busy_poll = READ_ONCE(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) @@ -466,6 +549,12 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi) { } +static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + return -EOPNOTSUPP; +} + #endif /* CONFIG_NET_RX_BUSY_POLL */ /* @@ -678,12 +767,6 @@ static void ep_done_scan(struct eventpoll *ep, write_unlock_irq(&ep->lock); } -static void epi_rcu_free(struct rcu_head *head) -{ - struct epitem *epi = container_of(head, struct epitem, rcu); - kmem_cache_free(epi_cache, epi); -} - static void ep_get(struct eventpoll *ep) { refcount_inc(&ep->refcount); @@ -767,7 +850,7 @@ static bool __ep_remove(struct eventpoll *ep, struct epitem *epi, bool force) * ep->mtx. The rcu read side, reverse_path_check_proc(), does not make * use of the rbn field. */ - call_rcu(&epi->rcu, epi_rcu_free); + kfree_rcu(epi, rcu); percpu_counter_dec(&ep->user->epoll_watches); return ep_refcount_dec_and_test(ep); @@ -825,6 +908,27 @@ 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; @@ -931,6 +1035,8 @@ 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, }; /* @@ -1153,7 +1259,7 @@ static inline bool chain_epi_lockless(struct epitem *epi) * This callback takes a read lock in order not to contend with concurrent * events from another file descriptor, thus all modifications to ->rdllist * or ->ovflist are lockless. Read lock is paired with the write lock from - * ep_scan_ready_list(), which stops all list modifications and guarantees + * ep_start/done_scan(), which stops all list modifications and guarantees * that lists state is seen correctly. * * Another thing worth to mention is that ep_poll_callback() can be called @@ -1751,7 +1857,7 @@ static int ep_send_events(struct eventpoll *ep, * availability. At this point, no one can insert * into ep->rdllist besides us. The epoll_ctl() * callers are locked out by - * ep_scan_ready_list() holding "mtx" and the + * ep_send_events() holding "mtx" and the * poll callback will queue them in ep->ovflist. */ list_add_tail(&epi->rdllink, &ep->rdllist); @@ -1904,7 +2010,7 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, __set_current_state(TASK_INTERRUPTIBLE); /* - * Do the final check under the lock. ep_scan_ready_list() + * Do the final check under the lock. ep_start/done_scan() * plays with two lists (->rdllist and ->ovflist) and there * is always a race when both lists are empty for short * period of time although events are pending, so lock is @@ -2058,6 +2164,11 @@ static int do_epoll_create(int flags) error = PTR_ERR(file); goto out_free_fd; } +#ifdef CONFIG_NET_RX_BUSY_POLL + ep->busy_poll_usecs = 0; + ep->busy_poll_budget = 0; + ep->prefer_busy_poll = false; +#endif ep->file = file; fd_install(fd, file); return fd; |