linux-master/ipc/sem.c

37  * - undo adjustments at process exit are limited to 0..SEMVMX.
102 	 *  - at task exit when performing undo adjustments (see exit_sem).
121 	struct list_head	list_id;	/* undo requests on this array */
133 	struct sem_undo		*undo;	 /* undo structure */
143 /* Each task has a list of undo requests. They are executed automatically
657 	un = q->undo;
675 			int undo = un->semadj[sop->sem_num] - sem_op;
676 			/* Exceeding the undo range is an error. */
677 			if (undo < (-SEMAEM - 1) || undo > SEMAEM)
679 			un->semadj[sop->sem_num] = undo;
696 	goto undo;
706 undo:
729 	un = q->undo;
737 	 * to shared memory and having to undo such changes in order to block
758 			int undo = un->semadj[sop->sem_num] - sem_op;
760 			/* Exceeding the undo range is an error. */
761 			if (undo < (-SEMAEM - 1) || undo > SEMAEM)
771 			int undo = un->semadj[sop->sem_num] - sem_op;
773 			un->semadj[sop->sem_num] = undo;
1151 	/* Free the existing undo structures for this semaphore set.  */
1733 	compat_uptr_t undo;
1840  * here.  We guarantee there is only one thread using this undo list,
1896  * find_alloc_undo - lookup (and if not present create) undo array
1900  * The function looks up (and if not present creates) the undo structure.
1901  * The size of the undo structure depends on the size of the semaphore
1924 	/* no undo structure around - allocate one. */
1940 	/* step 2: allocate new undo structure */
1960 	 * step 4: check for races: did someone else allocate the undo struct?
1968 	/* step 5: initialize & link new undo structure */
2086 	 * allocated an undo structure, it was invalidated by an RMID
2096 	queue.undo = un;
2324  * add semadj values to semaphores, free undo structures.
2325  * undo structures are not freed when semaphore arrays are destroyed
2420 				 * - Some unices ignore the undo entirely