X-Git-Url: http://git.madism.org/?p=~madcoder%2Fpwqr.git;a=blobdiff_plain;f=kernel%2Fpwqr.c;h=0d6b42ca187004e797fd1f395908daa5289656d3;hp=8592a006701bb9847e9a3f4fa9995a9a516c1222;hb=537958e9f81a6338fa2986ec56938d5a9fbc5166;hpb=c7cabb18799090c303666bab78827bc64ca2594e

diff --git a/kernel/pwqr.c b/kernel/pwqr.c
index 8592a00..0d6b42c 100644
--- a/kernel/pwqr.c
+++ b/kernel/pwqr.c
@@ -26,6 +26,7 @@
 #include <linux/init.h>
 #include <linux/kref.h>
 #include <linux/module.h>
+#include <linux/poll.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -60,7 +61,7 @@ struct pwqr_sb {
 	struct rcu_head		rcu;
 	struct timer_list	timer;
 	wait_queue_head_t	wqh;
-	pid_t			tgid;
+	wait_queue_head_t	wqh_poll;
 
 	unsigned		concurrency;
 	unsigned		registered;
@@ -134,7 +135,7 @@ static void pwqr_sb_timer_cb(unsigned long arg)
 			wake_up_locked(&sb->wqh);
 	}
 	if (sb->running > sb->concurrency) {
-		/* See ../Documentation/pwqr.adoc */
+		wake_up_poll(&sb->wqh_poll, POLLIN);
 	}
 	pwqr_sb_unlock_irqrestore(sb, flags);
 }
@@ -149,8 +150,7 @@ static struct pwqr_sb *pwqr_sb_create(void)
 
 	kref_init(&sb->kref);
 	init_waitqueue_head(&sb->wqh);
-	sb->tgid        = current->tgid;
-	sb->concurrency = num_online_cpus();
+	sb->concurrency    = num_online_cpus();
 	init_timer(&sb->timer);
 	sb->timer.function = pwqr_sb_timer_cb;
 	sb->timer.data     = (unsigned long)sb;
@@ -176,6 +176,7 @@ static void pwqr_sb_release(struct kref *kref)
 	struct pwqr_sb *sb = container_of(kref, struct pwqr_sb, kref);
 
 	del_timer_sync(&sb->timer);
+	wake_up_poll(&sb->wqh_poll, POLLHUP);
 	call_rcu(&sb->rcu, pwqr_sb_finalize);
 }
 static inline void pwqr_sb_put(struct pwqr_sb *sb)
@@ -372,9 +373,76 @@ static int pwqr_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static unsigned int pwqr_poll(struct file *filp, poll_table *wait)
+{
+	struct pwqr_sb *sb = filp->private_data;
+	unsigned int events = 0;
+	unsigned long flags;
+
+	poll_wait(filp, &sb->wqh_poll, wait);
+
+	pwqr_sb_lock_irqsave(sb, flags);
+	if (sb->running > sb->concurrency)
+		events |= POLLIN;
+	if (sb->state < 0)
+		events |= POLLHUP;
+	pwqr_sb_unlock_irqrestore(sb, flags);
+
+	return events;
+}
+
+static inline ssize_t pwqr_sb_read(struct pwqr_sb *sb, int no_wait, u32 *cnt)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	ssize_t rc = -EAGAIN;
+
+	spin_lock_irq(&sb->wqh.lock);
+	if (sb->running > sb->concurrency) {
+		rc = 0;
+	} else if (!no_wait) {
+		add_wait_queue(&sb->wqh_poll, &wait);
+		for (;;) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			if (sb->running > sb->concurrency) {
+				rc = 0;
+				break;
+			}
+			if (signal_pending(current)) {
+				rc = -ERESTARTSYS;
+				break;
+			}
+			spin_unlock_irq(&sb->wqh.lock);
+			schedule();
+			spin_lock_irq(&sb->wqh.lock);
+		}
+		remove_wait_queue(&sb->wqh_poll, &wait);
+		__set_current_state(TASK_RUNNING);
+	}
+	if (likely(rc == 0))
+		*cnt = sb->running - sb->concurrency;
+	spin_unlock_irq(&sb->wqh.lock);
+
+	return rc;
+}
+
+static ssize_t
+pwqr_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct pwqr_sb *sb = filp->private_data;
+	u32 cnt = 0;
+	ssize_t rc;
+
+	if (count < sizeof(cnt))
+		return -EINVAL;
+	rc = pwqr_sb_read(sb, filp->f_flags & O_NONBLOCK, &cnt);
+	if (rc < 0)
+		return rc;
+	return put_user(cnt, (u32 __user *)buf) ? -EFAULT : sizeof(cnt);
+}
+
 static long
 do_pwqr_wait(struct pwqr_sb *sb, struct pwqr_task *pwqt,
-	    int is_wait, struct pwqr_ioc_wait __user *arg)
+	     int is_wait, struct pwqr_ioc_wait __user *arg)
 {
 	unsigned long flags;
 	struct pwqr_ioc_wait wait;
@@ -417,7 +485,6 @@ do_pwqr_wait(struct pwqr_sb *sb, struct pwqr_task *pwqt,
 	/* @ see <wait_event_interruptible_exclusive_locked_irq> */
 	if (likely(sb->state >= 0)) {
 		DEFINE_WAIT(__wait);
-
 		__wait.flags |= WQ_FLAG_EXCLUSIVE;
 
 		if (is_wait) {
@@ -428,9 +495,9 @@ do_pwqr_wait(struct pwqr_sb *sb, struct pwqr_task *pwqt,
 			__add_wait_queue_tail(&sb->wqh, &__wait);
 		}
 		__pwqr_sb_update_state(sb, -1);
-		set_current_state(TASK_INTERRUPTIBLE);
 
 		do {
+			set_current_state(TASK_INTERRUPTIBLE);
 			if (sb->overcommit_wakes)
 				break;
 			if (signal_pending(current)) {
@@ -448,13 +515,13 @@ do_pwqr_wait(struct pwqr_sb *sb, struct pwqr_task *pwqt,
 
 		__remove_wait_queue(&sb->wqh, &__wait);
 		__set_current_state(TASK_RUNNING);
-
 		if (is_wait) {
 			sb->waiting--;
 		} else {
 			sb->parked--;
 		}
 		__pwqr_sb_update_state(sb, 1);
+
 		if (sb->overcommit_wakes)
 			sb->overcommit_wakes--;
 		if (sb->waiting + sb->running > sb->concurrency)
@@ -563,9 +630,6 @@ static long pwqr_ioctl(struct file *filp, unsigned command, unsigned long arg)
 	struct pwqr_task   *pwqt;
 	int rc = 0;
 
-	if (sb->tgid != current->tgid)
-		return -EBADFD;
-
 	switch (command) {
 	case PWQR_GET_CONC:
 		return sb->concurrency;
@@ -619,6 +683,9 @@ static const struct file_operations pwqr_dev_fops = {
 	.owner		= THIS_MODULE,
 	.open		= pwqr_open,
 	.release	= pwqr_release,
+	.poll		= pwqr_poll,
+	.read		= pwqr_read,
+	.llseek		= noop_llseek,
 	.unlocked_ioctl	= pwqr_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= pwqr_ioctl,