From 6b3e017e5d25f15da73f7700f7f2ac553ef1a2e9 Mon Sep 17 00:00:00 2001 From: Christian Ehrhardt Date: Thu, 8 Dec 2016 14:07:29 +0100 Subject: Imported Upstream version 16.11 Change-Id: I1944c65ddc88a9ad70f8c0eb6731552b84fbcb77 Signed-off-by: Christian Ehrhardt --- lib/librte_vhost/fd_man.c | 299 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 299 insertions(+) create mode 100644 lib/librte_vhost/fd_man.c (limited to 'lib/librte_vhost/fd_man.c') diff --git a/lib/librte_vhost/fd_man.c b/lib/librte_vhost/fd_man.c new file mode 100644 index 00000000..2d3eeb7d --- /dev/null +++ b/lib/librte_vhost/fd_man.c @@ -0,0 +1,299 @@ +/*- + * BSD LICENSE + * + * Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "fd_man.h" + +/** + * Returns the index in the fdset for a given fd. + * If fd is -1, it means to search for a free entry. + * @return + * index for the fd, or -1 if fd isn't in the fdset. + */ +static int +fdset_find_fd(struct fdset *pfdset, int fd) +{ + int i; + + if (pfdset == NULL) + return -1; + + for (i = 0; i < MAX_FDS && pfdset->fd[i].fd != fd; i++) + ; + + return i == MAX_FDS ? -1 : i; +} + +static int +fdset_find_free_slot(struct fdset *pfdset) +{ + return fdset_find_fd(pfdset, -1); +} + +static int +fdset_add_fd(struct fdset *pfdset, int idx, int fd, + fd_cb rcb, fd_cb wcb, void *dat) +{ + struct fdentry *pfdentry; + + if (pfdset == NULL || idx >= MAX_FDS || fd >= FD_SETSIZE) + return -1; + + pfdentry = &pfdset->fd[idx]; + pfdentry->fd = fd; + pfdentry->rcb = rcb; + pfdentry->wcb = wcb; + pfdentry->dat = dat; + + return 0; +} + +/** + * Fill the read/write fd_set with the fds in the fdset. + * @return + * the maximum fds filled in the read/write fd_set. + */ +static int +fdset_fill(fd_set *rfset, fd_set *wfset, struct fdset *pfdset) +{ + struct fdentry *pfdentry; + int i, maxfds = -1; + int num = MAX_FDS; + + if (pfdset == NULL) + return -1; + + for (i = 0; i < num; i++) { + pfdentry = &pfdset->fd[i]; + if (pfdentry->fd != -1) { + int added = 0; + if (pfdentry->rcb && rfset) { + FD_SET(pfdentry->fd, rfset); + added = 1; + } + if (pfdentry->wcb && wfset) { + FD_SET(pfdentry->fd, wfset); + added = 1; + } + if (added) + maxfds = pfdentry->fd < maxfds ? + maxfds : pfdentry->fd; + } + } + return maxfds; +} + +void +fdset_init(struct fdset *pfdset) +{ + int i; + + if (pfdset == NULL) + return; + + for (i = 0; i < MAX_FDS; i++) { + pfdset->fd[i].fd = -1; + pfdset->fd[i].dat = NULL; + } + pfdset->num = 0; +} + +/** + * Register the fd in the fdset with read/write handler and context. + */ +int +fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, void *dat) +{ + int i; + + if (pfdset == NULL || fd == -1) + return -1; + + pthread_mutex_lock(&pfdset->fd_mutex); + + /* Find a free slot in the list. */ + i = fdset_find_free_slot(pfdset); + if (i == -1 || fdset_add_fd(pfdset, i, fd, rcb, wcb, dat) < 0) { + pthread_mutex_unlock(&pfdset->fd_mutex); + return -2; + } + + pfdset->num++; + + pthread_mutex_unlock(&pfdset->fd_mutex); + + return 0; +} + +/** + * Unregister the fd from the fdset. + * Returns context of a given fd or NULL. + */ +void * +fdset_del(struct fdset *pfdset, int fd) +{ + int i; + void *dat = NULL; + + if (pfdset == NULL || fd == -1) + return NULL; + + do { + pthread_mutex_lock(&pfdset->fd_mutex); + + i = fdset_find_fd(pfdset, fd); + if (i != -1 && pfdset->fd[i].busy == 0) { + /* busy indicates r/wcb is executing! */ + dat = pfdset->fd[i].dat; + pfdset->fd[i].fd = -1; + pfdset->fd[i].rcb = pfdset->fd[i].wcb = NULL; + pfdset->fd[i].dat = NULL; + pfdset->num--; + i = -1; + } + pthread_mutex_unlock(&pfdset->fd_mutex); + } while (i != -1); + + return dat; +} + +/** + * Unregister the fd at the specified slot from the fdset. + */ +static void +fdset_del_slot(struct fdset *pfdset, int index) +{ + if (pfdset == NULL || index < 0 || index >= MAX_FDS) + return; + + pthread_mutex_lock(&pfdset->fd_mutex); + + pfdset->fd[index].fd = -1; + pfdset->fd[index].rcb = pfdset->fd[index].wcb = NULL; + pfdset->fd[index].dat = NULL; + pfdset->num--; + + pthread_mutex_unlock(&pfdset->fd_mutex); +} + +/** + * This functions runs in infinite blocking loop until there is no fd in + * pfdset. It calls corresponding r/w handler if there is event on the fd. + * + * Before the callback is called, we set the flag to busy status; If other + * thread(now rte_vhost_driver_unregister) calls fdset_del concurrently, it + * will wait until the flag is reset to zero(which indicates the callback is + * finished), then it could free the context after fdset_del. + */ +void +fdset_event_dispatch(struct fdset *pfdset) +{ + fd_set rfds, wfds; + int i, maxfds; + struct fdentry *pfdentry; + int num = MAX_FDS; + fd_cb rcb, wcb; + void *dat; + int fd; + int remove1, remove2; + int ret; + + if (pfdset == NULL) + return; + + while (1) { + struct timeval tv; + tv.tv_sec = 1; + tv.tv_usec = 0; + FD_ZERO(&rfds); + FD_ZERO(&wfds); + pthread_mutex_lock(&pfdset->fd_mutex); + + maxfds = fdset_fill(&rfds, &wfds, pfdset); + + pthread_mutex_unlock(&pfdset->fd_mutex); + + /* + * When select is blocked, other threads might unregister + * listenfds from and register new listenfds into fdset. + * When select returns, the entries for listenfds in the fdset + * might have been updated. It is ok if there is unwanted call + * for new listenfds. + */ + ret = select(maxfds + 1, &rfds, &wfds, NULL, &tv); + if (ret <= 0) + continue; + + for (i = 0; i < num; i++) { + remove1 = remove2 = 0; + pthread_mutex_lock(&pfdset->fd_mutex); + pfdentry = &pfdset->fd[i]; + fd = pfdentry->fd; + rcb = pfdentry->rcb; + wcb = pfdentry->wcb; + dat = pfdentry->dat; + pfdentry->busy = 1; + pthread_mutex_unlock(&pfdset->fd_mutex); + if (fd >= 0 && FD_ISSET(fd, &rfds) && rcb) + rcb(fd, dat, &remove1); + if (fd >= 0 && FD_ISSET(fd, &wfds) && wcb) + wcb(fd, dat, &remove2); + pfdentry->busy = 0; + /* + * fdset_del needs to check busy flag. + * We don't allow fdset_del to be called in callback + * directly. + */ + /* + * When we are to clean up the fd from fdset, + * because the fd is closed in the cb, + * the old fd val could be reused by when creates new + * listen fd in another thread, we couldn't call + * fd_set_del. + */ + if (remove1 || remove2) + fdset_del_slot(pfdset, i); + } + } +} -- cgit 1.2.3-korg