Merge branch 'for-usb-linus' of git.kernel.org/pub/scm/linux/kernel/git/sarah/xhci...

[pandora-kernel.git] / ipc / sem.c

diff --git a/ipc/sem.c b/ipc/sem.c
index fb13be1..5215a81 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -90,6 +90,52 @@
 #include <asm/uaccess.h>
 #include "util.h"
 
+/* One semaphore structure for each semaphore in the system. */
+struct sem {
+       int     semval;         /* current value */
+       int     sempid;         /* pid of last operation */
+       struct list_head sem_pending; /* pending single-sop operations */
+};
+
+/* One queue for each sleeping process in the system. */
+struct sem_queue {
+       struct list_head        simple_list; /* queue of pending operations */
+       struct list_head        list;    /* queue of pending operations */
+       struct task_struct      *sleeper; /* this process */
+       struct sem_undo         *undo;   /* undo structure */
+       int                     pid;     /* process id of requesting process */
+       int                     status;  /* completion status of operation */
+       struct sembuf           *sops;   /* array of pending operations */
+       int                     nsops;   /* number of operations */
+       int                     alter;   /* does *sops alter the array? */
+};
+
+/* Each task has a list of undo requests. They are executed automatically
+ * when the process exits.
+ */
+struct sem_undo {
+       struct list_head        list_proc;      /* per-process list: *
+                                                * all undos from one process
+                                                * rcu protected */
+       struct rcu_head         rcu;            /* rcu struct for sem_undo */
+       struct sem_undo_list    *ulp;           /* back ptr to sem_undo_list */
+       struct list_head        list_id;        /* per semaphore array list:
+                                                * all undos for one array */
+       int                     semid;          /* semaphore set identifier */
+       short                   *semadj;        /* array of adjustments */
+                                               /* one per semaphore */
+};
+
+/* sem_undo_list controls shared access to the list of sem_undo structures
+ * that may be shared among all a CLONE_SYSVSEM task group.
+ */
+struct sem_undo_list {
+       atomic_t                refcnt;
+       spinlock_t              lock;
+       struct list_head        list_proc;
+};
+
+
 #define sem_ids(ns)    ((ns)->ids[IPC_SEM_IDS])
 
 #define sem_unlock(sma)                ipc_unlock(&(sma)->sem_perm)
@@ -1426,6 +1472,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 
        queue.status = -EINTR;
        queue.sleeper = current;
+
+sleep_again:
        current->state = TASK_INTERRUPTIBLE;
        sem_unlock(sma);
 
@@ -1478,6 +1526,13 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
         */
        if (timeout && jiffies_left == 0)
                error = -EAGAIN;
+
+       /*
+        * If the wakeup was spurious, just retry
+        */
+       if (error == -EINTR && !signal_pending(current))
+               goto sleep_again;
+
        unlink_queue(sma, &queue);
 
 out_unlock_free: