Commit 758a6ba3 authored by Manfred Spraul's avatar Manfred Spraul Committed by Linus Torvalds
Browse files

ipc/sem.c: rename try_atomic_semop() to perform_atomic_semop(), docu update 



Cleanup: Some minor points that I noticed while writing the previous
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: default avatarManfred Spraul <manfred@colorfullife.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d12e1e50

ipc/sem.c

+21 −11
Original line number Diff line number Diff line
@@ -154,12 +154,15 @@ 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]
@@ -536,12 +539,19 @@ 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;
@@ -724,7 +734,7 @@ 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,

		error = perform_atomic_semop(sma, q->sops, q->nsops,

						 q->undo, q->pid);



		if (error <= 0) {
@@ -838,7 +848,7 @@ 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? */
@@ -1686,7 +1696,6 @@ 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)

{
@@ -1784,7 +1793,8 @@ 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);

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