[PATCH v2 3/4] sunrpc: convert queue_wait from global to per-cache-detail waitqueue

[Jeff Layton <jlayton@kernel.org>]

The queue_wait waitqueue is currently a file-scoped global, so a
wake_up for one cache_detail wakes pollers on all caches. Convert it
to a per-cache-detail field so that only pollers on the relevant cache
are woken.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 include/linux/sunrpc/cache.h | 2 ++
 net/sunrpc/cache.c           | 7 +++----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 3d32dd1f7b05d35562d2064fed69877b3950fb51..031379efba24d40f64ce346cf1032261d4b98d05 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -16,6 +16,7 @@
 #include <linux/atomic.h>
 #include <linux/kstrtox.h>
 #include <linux/proc_fs.h>
+#include <linux/wait.h>
 
 /*
  * Each cache requires:
@@ -114,6 +115,7 @@ struct cache_detail {
 	/* fields for communication over channel */
 	struct list_head	queue;
 	spinlock_t		queue_lock;
+	wait_queue_head_t	queue_wait;
 
 	atomic_t		writers;		/* how many time is /channel open */
 	time64_t		last_close;		/* if no writers, when did last close */
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 1cfaae488c6c67a9797511804e4bbba16bcc70ae..fd02dca1f07afec2f09c591037bac3ea3e8d7e17 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -401,6 +401,7 @@ void sunrpc_init_cache_detail(struct cache_detail *cd)
 	spin_lock_init(&cd->hash_lock);
 	INIT_LIST_HEAD(&cd->queue);
 	spin_lock_init(&cd->queue_lock);
+	init_waitqueue_head(&cd->queue_wait);
 	spin_lock(&cache_list_lock);
 	cd->nextcheck = 0;
 	cd->entries = 0;
@@ -970,8 +971,6 @@ static ssize_t cache_write(struct file *filp, const char __user *buf,
 	return ret;
 }
 
-static DECLARE_WAIT_QUEUE_HEAD(queue_wait);
-
 static __poll_t cache_poll(struct file *filp, poll_table *wait,
 			       struct cache_detail *cd)
 {
@@ -979,7 +978,7 @@ static __poll_t cache_poll(struct file *filp, poll_table *wait,
 	struct cache_reader *rp = filp->private_data;
 	struct cache_queue *cq;
 
-	poll_wait(filp, &queue_wait, wait);
+	poll_wait(filp, &cd->queue_wait, wait);
 
 	/* alway allow write */
 	mask = EPOLLOUT | EPOLLWRNORM;
@@ -1259,7 +1258,7 @@ static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
 		/* Lost a race, no longer PENDING, so don't enqueue */
 		ret = -EAGAIN;
 	spin_unlock(&detail->queue_lock);
-	wake_up(&queue_wait);
+	wake_up(&detail->queue_wait);
 	if (ret == -EAGAIN) {
 		kfree(buf);
 		kfree(crq);

-- 
2.53.0