Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751899Ab3EZJKv (ORCPT ); Sun, 26 May 2013 05:10:51 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:57772 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751711Ab3EZJKY (ORCPT ); Sun, 26 May 2013 05:10:24 -0400 From: Manfred Spraul To: Rik van Riel Cc: LKML , Andrew Morton , Davidlohr Bueso , hhuang@redhat.com, Linus Torvalds , Manfred Spraul Subject: [PATCH 4/4] ipc/sem.c: Rename try_atomic_semop() to perform_atomic_semop(), docu update Date: Sun, 26 May 2013 11:08:55 +0200 Message-Id: <1369559335-13491-5-git-send-email-manfred@colorfullife.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1369559335-13491-1-git-send-email-manfred@colorfullife.com> References: <1369559335-13491-1-git-send-email-manfred@colorfullife.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3634 Lines: 107 Final cleanup: Some minor points that I noticed while writing the previous 3 patches 1) The name try_atomic_semop() is misleading: The function performs the operation (if it is possible). 2) Some documentation updates. No real code change, a rename and documentation changes. Signed-off-by: Manfred Spraul --- ipc/sem.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/ipc/sem.c b/ipc/sem.c index 9ed3853..1dbb2fa 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -153,12 +153,15 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it); #define SEMOPM_FAST 64 /* ~ 372 bytes on stack */ /* - * linked list protection: + * Locking: * sem_undo.id_next, + * sem_array.complex_count, * sem_array.pending{_alter,_cont}, - * sem_array.sem_undo: sem_lock() for read/write + * sem_array.sem_undo: global sem_lock() for read/write * sem_undo.proc_next: only "current" is allowed to read/write that field. * + * sem_array.sem_base[i].pending_{const,alter}: + * global or semaphore sem_lock() for read/write */ #define sc_semmsl sem_ctls[0] @@ -535,12 +538,19 @@ SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg) return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params); } -/* - * Determine whether a sequence of semaphore operations would succeed - * all at once. Return 0 if yes, 1 if need to sleep, else return error code. +/** perform_atomic_semop - Perform (if possible) a semaphore operation + * @sma: semaphore array + * @sops: array with operations that should be checked + * @nsems: number of sops + * @un: undo array + * @pid: pid that did the change + * + * Returns 0 if the operation was possible. + * Returns 1 if the operation is impossible, the caller must sleep. + * Negative values are error codes. */ -static int try_atomic_semop (struct sem_array * sma, struct sembuf * sops, +static int perform_atomic_semop(struct sem_array *sma, struct sembuf *sops, int nsops, struct sem_undo *un, int pid) { int result, sem_op; @@ -723,8 +733,8 @@ static int wake_const_ops(struct sem_array *sma, int semnum, q = container_of(walk, struct sem_queue, list); walk = walk->next; - error = try_atomic_semop(sma, q->sops, q->nsops, - q->undo, q->pid); + error = perform_atomic_semop(sma, q->sops, q->nsops, + q->undo, q->pid); if (error <= 0) { /* operation completed, remove from queue & wakeup */ @@ -835,7 +845,7 @@ again: if (semnum != -1 && sma->sem_base[semnum].semval == 0) break; - error = try_atomic_semop(sma, q->sops, q->nsops, + error = perform_atomic_semop(sma, q->sops, q->nsops, q->undo, q->pid); /* Does q->sleeper still need to sleep? */ @@ -1658,7 +1668,6 @@ static int get_queue_result(struct sem_queue *q) return error; } - SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, unsigned, nsops, const struct timespec __user *, timeout) { @@ -1756,7 +1765,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, if (un && un->semid == -1) goto out_unlock_free; - error = try_atomic_semop (sma, sops, nsops, un, task_tgid_vnr(current)); + error = perform_atomic_semop(sma, sops, nsops, un, + task_tgid_vnr(current)); if (error <= 0) { if (alter && error == 0) do_smart_update(sma, sops, nsops, 1, &tasks); -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/