[PATCH 4/6] ipc/sem.c: Change perform_atomic_semop parameters

Manfred Spraul
2014-05-18T07:59:00Z

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: Manfred Spraul <manfred@colorfullife.com>
---
ipc/sem.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/ipc/sem.c b/ipc/sem.c
index 95d5bc5..7b1585d 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -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];
--
1.9.0