Commit d198cd6d authored by Manfred Spraul's avatar Manfred Spraul Committed by Linus Torvalds
Browse files

ipc/sem.c: change perform_atomic_semop parameters 



Right now, perform_atomic_semop gets the content of sem_queue as
individual fields.  Changes that, instead pass a pointer to sem_queue.

This is a preparation for the next patch: it uses sem_queue to store the
reason why a task must sleep.

Signed-off-by: default avatarManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2f2ed41d

ipc/sem.c

+19 −19
Original line number Diff line number Diff line
@@ -585,21 +585,23 @@ SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg) 
/**

 * perform_atomic_semop - Perform (if possible) a semaphore operation

 * @sma: semaphore array

 * @sops: array with operations that should be checked

 * @nsops: number of operations

 * @un: undo array

 * @pid: pid that did the change

 * @q: struct sem_queue that describes the operation

 *

 * 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 perform_atomic_semop(struct sem_array *sma, struct sembuf *sops,

			     int nsops, struct sem_undo *un, int pid)

static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)

{

	int result, sem_op;

	int result, sem_op, nsops, pid;

	struct sembuf *sop;

	struct sem *curr;

	struct sembuf *sops;

	struct sem_undo *un;



	sops = q->sops;

	nsops = q->nsops;

	un = q->undo;



	for (sop = sops; sop < sops + nsops; sop++) {

		curr = sma->sem_base + sop->sem_num;
@@ -627,6 +629,7 @@ static int perform_atomic_semop(struct sem_array *sma, struct sembuf *sops, 
	}



	sop--;

	pid = q->pid;

	while (sop >= sops) {

		sma->sem_base[sop->sem_num].sempid = pid;

		sop--;
@@ -779,8 +782,7 @@ static int wake_const_ops(struct sem_array *sma, int semnum, 
		q = container_of(walk, struct sem_queue, list);

		walk = walk->next;



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

						 q->undo, q->pid);

		error = perform_atomic_semop(sma, q);



		if (error <= 0) {

			/* operation completed, remove from queue & wakeup */
@@ -892,8 +894,7 @@ again: 
		if (semnum != -1 && sma->sem_base[semnum].semval == 0)

			break;



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

					 q->undo, q->pid);

		error = perform_atomic_semop(sma, q);



		/* Does q->sleeper still need to sleep? */

		if (error > 0)
@@ -1871,8 +1872,13 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, 
	if (un && un->semid == -1)

		goto out_unlock_free;



	error = perform_atomic_semop(sma, sops, nsops, un,

					task_tgid_vnr(current));

	queue.sops = sops;

	queue.nsops = nsops;

	queue.undo = un;

	queue.pid = task_tgid_vnr(current);

	queue.alter = alter;



	error = perform_atomic_semop(sma, &queue);

	if (error == 0) {

		/* If the operation was successful, then do

		 * the required updates.
@@ -1889,12 +1895,6 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, 
	 * task into the pending queue and go to sleep.

	 */



	queue.sops = sops;

	queue.nsops = nsops;

	queue.undo = un;

	queue.pid = task_tgid_vnr(current);

	queue.alter = alter;



	if (nsops == 1) {

		struct sem *curr;

		curr = &sma->sem_base[sops->sem_num];

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