signal: turn dequeue_signal_lock() into kernel_dequeue_signal()

1. Rename dequeue_signal_lock() to kernel_dequeue_signal(). This
   matches another "for kthreads only" kernel_sigaction() helper.

2. Remove the "tsk" and "mask" arguments, they are always current
   and current->blocked. And it is simply wrong if tsk != current.

3. We could also remove the 3rd "siginfo_t *info" arg but it looks
   potentially useful. However we can simplify the callers if we
   change kernel_dequeue_signal() to accept info => NULL.

4. Remove _irqsave, it is never called from atomic context.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 1b87623..93b3f99 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -444,9 +444,7 @@ static int nbd_thread_recv(struct nbd_device *nbd)
        spin_unlock_irqrestore(&nbd->tasks_lock, flags);
 
        if (signal_pending(current)) {
-               siginfo_t info;
-
-               ret = dequeue_signal_lock(current, &current->blocked, &info);
+               ret = kernel_dequeue_signal(NULL);
                dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal %d\n",
                         task_pid_nr(current), current->comm, ret);
                mutex_lock(&nbd->tx_lock);
@@ -560,11 +558,8 @@ static int nbd_thread_send(void *data)
                                         !list_empty(&nbd->waiting_queue));
 
                if (signal_pending(current)) {
-                       siginfo_t info;
-                       int ret;
+                       int ret = kernel_dequeue_signal(NULL);
 
-                       ret = dequeue_signal_lock(current, &current->blocked,
-                                                 &info);
                        dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal %d\n",
                                 task_pid_nr(current), current->comm, ret);
                        mutex_lock(&nbd->tx_lock);
@@ -592,10 +587,8 @@ static int nbd_thread_send(void *data)
        spin_unlock_irqrestore(&nbd->tasks_lock, flags);
 
        /* Clear maybe pending signals */
-       if (signal_pending(current)) {
-               siginfo_t info;
-               dequeue_signal_lock(current, &current->blocked, &info);
-       }
+       if (signal_pending(current))
+               kernel_dequeue_signal(NULL);
 
        return 0;
 }

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index cd54e72..5ec5338 100644 (file)
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -2345,7 +2345,6 @@ static void fsg_disable(struct usb_function *f)
 
 static void handle_exception(struct fsg_common *common)
 {
-       siginfo_t               info;
        int                     i;
        struct fsg_buffhd       *bh;
        enum fsg_state          old_state;
@@ -2357,8 +2356,7 @@ static void handle_exception(struct fsg_common *common)
         * into a high-priority EXIT exception.
         */
        for (;;) {
-               int sig =
-                       dequeue_signal_lock(current, &current->blocked, &info);
+               int sig = kernel_dequeue_signal(NULL);
                if (!sig)
                        break;
                if (sig != SIGUSR1) {

diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c
index bb9cebc..f3145fd 100644 (file)
--- a/fs/jffs2/background.c
+++ b/fs/jffs2/background.c
@@ -121,13 +121,12 @@ static int jffs2_garbage_collect_thread(void *_c)
                /* Put_super will send a SIGKILL and then wait on the sem.
                 */
                while (signal_pending(current) || freezing(current)) {
-                       siginfo_t info;
                        unsigned long signr;
 
                        if (try_to_freeze())
                                goto again;
 
-                       signr = dequeue_signal_lock(current, &current->blocked, &info);
+                       signr = kernel_dequeue_signal(NULL);
 
                        switch(signr) {
                        case SIGSTOP:

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 923ec1a..3d54924 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2462,14 +2462,15 @@ extern void ignore_signals(struct task_struct *);
 extern void flush_signal_handlers(struct task_struct *, int force_default);
 extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
 
-static inline int dequeue_signal_lock(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
+static inline int kernel_dequeue_signal(siginfo_t *info)
 {
-       unsigned long flags;
+       struct task_struct *tsk = current;
+       siginfo_t __info;
        int ret;
 
-       spin_lock_irqsave(&tsk->sighand->siglock, flags);
-       ret = dequeue_signal(tsk, mask, info);
-       spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+       spin_lock_irq(&tsk->sighand->siglock);
+       ret = dequeue_signal(tsk, &tsk->blocked, info ?: &__info);
+       spin_unlock_irq(&tsk->sighand->siglock);
 
        return ret;
 }