Module: xenomai-forge Branch: next Commit: 97e243b81194de9cc4cc6ef9d0232f61e5f609e0 URL: http://git.xenomai.org/?p=xenomai-forge.git;a=commit;h=97e243b81194de9cc4cc6ef9d0232f61e5f609e0
Author: Philippe Gerum <r...@xenomai.org> Date: Wed May 7 16:07:27 2014 +0200 copperplate/notifier: signal suspended thread directly The notifier will remain dedicated to supporting thread-directed suspend/resume operations eventually, and there is no gain in issuing a signaled message compared to solely signaling the target thread. Therefore we drop the pipe formerly used to trigger a fasync notification on the read side, replacing it by direct signaling of the target thread. This patch is a slightly updated version of Matthias Schneider's proposal: http://www.xenomai.org/pipermail/xenomai/2014-May/030822.html --- include/copperplate/notifier.h | 3 +- lib/copperplate/notifier.c | 105 ++++++---------------------------------- 2 files changed, 17 insertions(+), 91 deletions(-) diff --git a/include/copperplate/notifier.h b/include/copperplate/notifier.h index 13bf588..61e2ec4 100644 --- a/include/copperplate/notifier.h +++ b/include/copperplate/notifier.h @@ -23,8 +23,7 @@ struct notifier { pid_t owner; - int psfd[2]; - int pwfd[2]; + int waitfd[2]; struct pvholder link; }; diff --git a/lib/copperplate/notifier.c b/lib/copperplate/notifier.c index 4b3988a..0e8c832 100644 --- a/lib/copperplate/notifier.c +++ b/lib/copperplate/notifier.c @@ -36,65 +36,24 @@ static struct sigaction notifier_old_sa; static void notifier_sighandler(int sig, siginfo_t *siginfo, void *uc) { - int ret, matched = 0; struct notifier *nf; pid_t tid; - char c; tid = copperplate_get_tid(); if (pvlist_empty(¬ifier_list)) - goto hand_over; + goto ouch; /* We may NOT alter the notifier list, but only scan it. */ pvlist_for_each_entry(nf, ¬ifier_list, link) { - if (nf->psfd[0] != siginfo->si_fd) - continue; - - matched = 1; - /* - * Paranoid: misdirected notifications should never - * happen with F_SETOWN_EX invoked for the - * notification fildes. - */ - if (nf->owner != tid) - continue; - - for (;;) { - ret = read(nf->psfd[0], &c, 1); - if (ret > 0) - notifier_wait(nf); - else if (ret == 0 || errno != EINTR) - break; + if (nf->owner == tid) { + notifier_wait(nf); + return; } - - return; - } - - /* - * Paranoid: we may have received a valid notification on the - * wrong thread: bail out silently, assuming the recipient - * will find out eventually. - */ - if (matched) - return; - -hand_over: - if (notifier_old_sa.sa_sigaction) { - /* - * This is our best effort to relay any unprocessed - * event to the user-defined handler for SIGNOTIFY we - * might have overriden in notifier_pkg_init(). The - * application code should set this handler prior to - * calling copperplate_init(), so that we know about it. The - * signal setup flags will be ours however - * (i.e. SA_SIGINFO + BSD semantics). - */ - notifier_old_sa.sa_sigaction(sig, siginfo, uc); - return; } - - panic("received spurious notification on thread[%d] [sig=%d, code=%d, fd=%d]", +ouch: + panic("received spurious notification on thread[%d] " + "(sig=%d, code=%d, fd=%d)", tid, sig, siginfo->si_code, siginfo->si_fd); } @@ -116,19 +75,11 @@ static void unlock_notifier_list(sigset_t *oset) int notifier_init(struct notifier *nf, pid_t pid) { - struct f_owner_ex owner; sigset_t oset; - int fd, ret; - - if (pipe(nf->psfd) < 0) { - ret = -errno; - goto fail; - } + int ret; - if (pipe(nf->pwfd) < 0) { + if (pipe(nf->waitfd) < 0) { ret = -errno; - close(nf->psfd[0]); - close(nf->psfd[1]); goto fail; } @@ -140,23 +91,6 @@ int notifier_init(struct notifier *nf, pid_t pid) unlock_notifier_list(&oset); pop_cleanup_lock(¬ifier_lock); - fd = nf->psfd[0]; - fcntl(fd, F_SETSIG, SIGNOTIFY); - owner.type = F_OWNER_TID; - owner.pid = nf->owner; - fcntl(fd, F_SETOWN_EX, &owner); - fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_ASYNC | O_NONBLOCK); - fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC); - /* - * Somewhat paranoid, but makes sure no flow control will ever - * block us when signaling a notifier object. - */ - fd = nf->psfd[1]; - fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK); - fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC); - fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK); - fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC); - return 0; fail: warning("failed to create notifier pipe"); @@ -173,25 +107,18 @@ void notifier_destroy(struct notifier *nf) pvlist_remove(&nf->link); unlock_notifier_list(&oset); pop_cleanup_lock(¬ifier_lock); - close(nf->psfd[0]); - close(nf->psfd[1]); - close(nf->pwfd[0]); /* May fail if disabled. */ - close(nf->pwfd[1]); + close(nf->waitfd[0]); /* May fail if disabled. */ + close(nf->waitfd[1]); } void notifier_signal(struct notifier *nf) { - char c = 0; - int ret; - - do - ret = write(nf->psfd[1], &c, 1); - while (ret == -1 && errno == EINTR); + copperplate_kill_tid(nf->owner, SIGNOTIFY); } void notifier_disable(struct notifier *nf) { - close(nf->pwfd[0]); + close(nf->waitfd[0]); } void notifier_release(struct notifier *nf) @@ -200,17 +127,17 @@ void notifier_release(struct notifier *nf) int ret; do - ret = write(nf->pwfd[1], &c, 1); + ret = write(nf->waitfd[1], &c, 1); while (ret == -1 && errno == EINTR); } -void notifier_wait(const struct notifier *nf) /* sighandler context */ +void notifier_wait(const struct notifier *nf) { int ret; char c; do - ret = read(nf->pwfd[0], &c, 1); + ret = read(nf->waitfd[0], &c, 1); while (ret == -1 && errno == EINTR); } _______________________________________________ Xenomai-git mailing list Xenomai-git@xenomai.org http://www.xenomai.org/mailman/listinfo/xenomai-git
