The global queue_lock serializes all upcall queue operations across
every cache_detail instance. Convert it to a per-cache-detail spinlock
so that different caches (e.g. auth.unix.ip vs nfsd.fh) no longer
contend with each other on queue operations.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 include/linux/sunrpc/cache.h |  1 +
 net/sunrpc/cache.c           | 47 ++++++++++++++++++++++----------------------
 2 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index e783132e481ff2593fdc5d323f7b3a08f85d4cd8..3d32dd1f7b05d35562d2064fed69877b3950fb51 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -113,6 +113,7 @@ struct cache_detail {
 
 	/* fields for communication over channel */
 	struct list_head	queue;
+	spinlock_t		queue_lock;
 
 	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 86b3fd5a429d77f7f917f398a02cb7a5ff8dd1e0..1cfaae488c6c67a9797511804e4bbba16bcc70ae 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -400,6 +400,7 @@ 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);
 	spin_lock(&cache_list_lock);
 	cd->nextcheck = 0;
 	cd->entries = 0;
@@ -803,8 +804,6 @@ void cache_clean_deferred(void *owner)
  *
  */
 
-static DEFINE_SPINLOCK(queue_lock);
-
 struct cache_queue {
 	struct list_head	list;
 	int			reader;	/* if 0, then request */
@@ -847,7 +846,7 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 	inode_lock(inode); /* protect against multiple concurrent
 			      * readers on this file */
  again:
-	spin_lock(&queue_lock);
+	spin_lock(&cd->queue_lock);
 	/* need to find next request */
 	while (rp->q.list.next != &cd->queue &&
 	       list_entry(rp->q.list.next, struct cache_queue, list)
@@ -856,7 +855,7 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 		list_move(&rp->q.list, next);
 	}
 	if (rp->q.list.next == &cd->queue) {
-		spin_unlock(&queue_lock);
+		spin_unlock(&cd->queue_lock);
 		inode_unlock(inode);
 		WARN_ON_ONCE(rp->offset);
 		return 0;
@@ -865,7 +864,7 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 	WARN_ON_ONCE(rq->q.reader);
 	if (rp->offset == 0)
 		rq->readers++;
-	spin_unlock(&queue_lock);
+	spin_unlock(&cd->queue_lock);
 
 	if (rq->len == 0) {
 		err = cache_request(cd, rq);
@@ -876,9 +875,9 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 
 	if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
 		err = -EAGAIN;
-		spin_lock(&queue_lock);
+		spin_lock(&cd->queue_lock);
 		list_move(&rp->q.list, &rq->q.list);
-		spin_unlock(&queue_lock);
+		spin_unlock(&cd->queue_lock);
 	} else {
 		if (rp->offset + count > rq->len)
 			count = rq->len - rp->offset;
@@ -888,26 +887,26 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 		rp->offset += count;
 		if (rp->offset >= rq->len) {
 			rp->offset = 0;
-			spin_lock(&queue_lock);
+			spin_lock(&cd->queue_lock);
 			list_move(&rp->q.list, &rq->q.list);
-			spin_unlock(&queue_lock);
+			spin_unlock(&cd->queue_lock);
 		}
 		err = 0;
 	}
  out:
 	if (rp->offset == 0) {
 		/* need to release rq */
-		spin_lock(&queue_lock);
+		spin_lock(&cd->queue_lock);
 		rq->readers--;
 		if (rq->readers == 0 &&
 		    !test_bit(CACHE_PENDING, &rq->item->flags)) {
 			list_del(&rq->q.list);
-			spin_unlock(&queue_lock);
+			spin_unlock(&cd->queue_lock);
 			cache_put(rq->item, cd);
 			kfree(rq->buf);
 			kfree(rq);
 		} else
-			spin_unlock(&queue_lock);
+			spin_unlock(&cd->queue_lock);
 	}
 	if (err == -EAGAIN)
 		goto again;
@@ -988,7 +987,7 @@ static __poll_t cache_poll(struct file *filp, poll_table *wait,
 	if (!rp)
 		return mask;
 
-	spin_lock(&queue_lock);
+	spin_lock(&cd->queue_lock);
 
 	for (cq= &rp->q; &cq->list != &cd->queue;
 	     cq = list_entry(cq->list.next, struct cache_queue, list))
@@ -996,7 +995,7 @@ static __poll_t cache_poll(struct file *filp, poll_table *wait,
 			mask |= EPOLLIN | EPOLLRDNORM;
 			break;
 		}
-	spin_unlock(&queue_lock);
+	spin_unlock(&cd->queue_lock);
 	return mask;
 }
 
@@ -1011,7 +1010,7 @@ static int cache_ioctl(struct inode *ino, struct file *filp,
 	if (cmd != FIONREAD || !rp)
 		return -EINVAL;
 
-	spin_lock(&queue_lock);
+	spin_lock(&cd->queue_lock);
 
 	/* only find the length remaining in current request,
 	 * or the length of the next request
@@ -1024,7 +1023,7 @@ static int cache_ioctl(struct inode *ino, struct file *filp,
 			len = cr->len - rp->offset;
 			break;
 		}
-	spin_unlock(&queue_lock);
+	spin_unlock(&cd->queue_lock);
 
 	return put_user(len, (int __user *)arg);
 }
@@ -1046,9 +1045,9 @@ static int cache_open(struct inode *inode, struct file *filp,
 		rp->offset = 0;
 		rp->q.reader = 1;
 
-		spin_lock(&queue_lock);
+		spin_lock(&cd->queue_lock);
 		list_add(&rp->q.list, &cd->queue);
-		spin_unlock(&queue_lock);
+		spin_unlock(&cd->queue_lock);
 	}
 	if (filp->f_mode & FMODE_WRITE)
 		atomic_inc(&cd->writers);
@@ -1064,7 +1063,7 @@ static int cache_release(struct inode *inode, struct file *filp,
 	if (rp) {
 		struct cache_request *rq = NULL;
 
-		spin_lock(&queue_lock);
+		spin_lock(&cd->queue_lock);
 		if (rp->offset) {
 			struct cache_queue *cq;
 			for (cq = &rp->q; &cq->list != &cd->queue;
@@ -1086,7 +1085,7 @@ static int cache_release(struct inode *inode, struct file *filp,
 			rp->offset = 0;
 		}
 		list_del(&rp->q.list);
-		spin_unlock(&queue_lock);
+		spin_unlock(&cd->queue_lock);
 
 		if (rq) {
 			cache_put(rq->item, cd);
@@ -1113,7 +1112,7 @@ static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
 	struct cache_request *cr;
 	LIST_HEAD(dequeued);
 
-	spin_lock(&queue_lock);
+	spin_lock(&detail->queue_lock);
 	list_for_each_entry_safe(cq, tmp, &detail->queue, list)
 		if (!cq->reader) {
 			cr = container_of(cq, struct cache_request, q);
@@ -1126,7 +1125,7 @@ static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch)
 				continue;
 			list_move(&cr->q.list, &dequeued);
 		}
-	spin_unlock(&queue_lock);
+	spin_unlock(&detail->queue_lock);
 	while (!list_empty(&dequeued)) {
 		cr = list_entry(dequeued.next, struct cache_request, q.list);
 		list_del(&cr->q.list);
@@ -1251,7 +1250,7 @@ static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
 	crq->buf = buf;
 	crq->len = 0;
 	crq->readers = 0;
-	spin_lock(&queue_lock);
+	spin_lock(&detail->queue_lock);
 	if (test_bit(CACHE_PENDING, &h->flags)) {
 		crq->item = cache_get(h);
 		list_add_tail(&crq->q.list, &detail->queue);
@@ -1259,7 +1258,7 @@ static int cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
 	} else
 		/* Lost a race, no longer PENDING, so don't enqueue */
 		ret = -EAGAIN;
-	spin_unlock(&queue_lock);
+	spin_unlock(&detail->queue_lock);
 	wake_up(&queue_wait);
 	if (ret == -EAGAIN) {
 		kfree(buf);

-- 
2.53.0