Date: Sun, 30 Apr 2017 19:32:51 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r317610 - head/lib/libc/gen Message-ID: <201704301932.v3UJWpHH029579@repo.freebsd.org>
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Author: kib Date: Sun Apr 30 19:32:51 2017 New Revision: 317610 URL: https://svnweb.freebsd.org/changeset/base/317610 Log: Restructure normal (non-error) control flow in sem_close(). Do not retest for the found semaphore after the loop to look it up. Instead, handle both cases of last and non-last close simultaneously, which allows to consolidate the list unlock and successful return. Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/lib/libc/gen/sem_new.c Modified: head/lib/libc/gen/sem_new.c ============================================================================== --- head/lib/libc/gen/sem_new.c Sun Apr 30 18:39:31 2017 (r317609) +++ head/lib/libc/gen/sem_new.c Sun Apr 30 19:32:51 2017 (r317610) @@ -41,6 +41,7 @@ #include <fcntl.h> #include <pthread.h> #include <stdarg.h> +#include <stdbool.h> #include <stdlib.h> #include <string.h> #include <time.h> @@ -260,6 +261,7 @@ int _sem_close(sem_t *sem) { struct sem_nameinfo *ni; + bool last; if (sem_check_validity(sem) != 0) return (-1); @@ -274,21 +276,17 @@ _sem_close(sem_t *sem) _pthread_mutex_lock(&sem_llock); LIST_FOREACH(ni, &sem_list, next) { if (sem == ni->sem) { - if (--ni->open_count > 0) { - _pthread_mutex_unlock(&sem_llock); - return (0); + last = --ni->open_count == 0; + if (last) + LIST_REMOVE(ni, next); + _pthread_mutex_unlock(&sem_llock); + if (last) { + munmap(sem, sizeof(*sem)); + free(ni); } - break; + return (0); } } - - if (ni != NULL) { - LIST_REMOVE(ni, next); - _pthread_mutex_unlock(&sem_llock); - munmap(sem, sizeof(*sem)); - free(ni); - return (0); - } _pthread_mutex_unlock(&sem_llock); errno = EINVAL; return (-1);
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