NFS: replace global bl_wq with per-net one

This queue is used for sleeping in kernel and it have to be per-net since we
don't want to wake any other waiters except in out network nemespace.
BTW, move wq to per-net data is easy. But some way to handle upcall timeouts
have to be provided. On message destroy in case of timeout, tasks, waiting for
message to be delivered, should be awakened. Thus, some data required to
located the right wait queue. Chosen solution replaces rpc_pipe_msg object with
new introduced bl_pipe_msg object, containing rpc_pipe_msg and proper wq.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/blocklayout/blocklayoutdev.c b/fs/nfs/blocklayout/blocklayoutdev.c
index 1d58642..a5c88a5 100644
--- a/fs/nfs/blocklayout/blocklayoutdev.c
+++ b/fs/nfs/blocklayout/blocklayoutdev.c
@@ -91,16 +91,18 @@
 	if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
 		return -EFAULT;
 
-	wake_up(&bl_wq);
+	wake_up(&nn->bl_wq);
 
 	return mlen;
 }
 
 void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 {
+	struct bl_pipe_msg *bl_pipe_msg = container_of(msg, struct bl_pipe_msg, msg);
+
 	if (msg->errno >= 0)
 		return;
-	wake_up(&bl_wq);
+	wake_up(bl_pipe_msg->bl_wq);
 }
 
 /*
@@ -112,7 +114,8 @@
 {
 	struct pnfs_block_dev *rv;
 	struct block_device *bd = NULL;
-	struct rpc_pipe_msg msg;
+	struct bl_pipe_msg bl_pipe_msg;
+	struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
 	struct bl_msg_hdr bl_msg = {
 		.type = BL_DEVICE_MOUNT,
 		.totallen = dev->mincount,
@@ -128,15 +131,16 @@
 	dprintk("%s: deviceid: %s, mincount: %d\n", __func__, dev->dev_id.data,
 		dev->mincount);
 
-	memset(&msg, 0, sizeof(msg));
-	msg.data = kzalloc(sizeof(bl_msg) + dev->mincount, GFP_NOFS);
-	if (!msg.data) {
+	bl_pipe_msg.bl_wq = &nn->bl_wq;
+	memset(msg, 0, sizeof(*msg));
+	msg->data = kzalloc(sizeof(bl_msg) + dev->mincount, GFP_NOFS);
+	if (!msg->data) {
 		rv = ERR_PTR(-ENOMEM);
 		goto out;
 	}
 
-	memcpy(msg.data, &bl_msg, sizeof(bl_msg));
-	dataptr = (uint8_t *) msg.data;
+	memcpy(msg->data, &bl_msg, sizeof(bl_msg));
+	dataptr = (uint8_t *) msg->data;
 	len = dev->mincount;
 	offset = sizeof(bl_msg);
 	for (i = 0; len > 0; i++) {
@@ -145,13 +149,13 @@
 		len -= PAGE_CACHE_SIZE;
 		offset += PAGE_CACHE_SIZE;
 	}
-	msg.len = sizeof(bl_msg) + dev->mincount;
+	msg->len = sizeof(bl_msg) + dev->mincount;
 
 	dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
-	add_wait_queue(&bl_wq, &wq);
-	rc = rpc_queue_upcall(nn->bl_device_pipe, &msg);
+	add_wait_queue(&nn->bl_wq, &wq);
+	rc = rpc_queue_upcall(nn->bl_device_pipe, msg);
 	if (rc < 0) {
-		remove_wait_queue(&bl_wq, &wq);
+		remove_wait_queue(&nn->bl_wq, &wq);
 		rv = ERR_PTR(rc);
 		goto out;
 	}
@@ -159,7 +163,7 @@
 	set_current_state(TASK_UNINTERRUPTIBLE);
 	schedule();
 	__set_current_state(TASK_RUNNING);
-	remove_wait_queue(&bl_wq, &wq);
+	remove_wait_queue(&nn->bl_wq, &wq);
 
 	if (reply->status != BL_DEVICE_REQUEST_PROC) {
 		dprintk("%s failed to open device: %d\n",
@@ -191,7 +195,7 @@
 		bd->bd_block_size);
 
 out:
-	kfree(msg.data);
+	kfree(msg->data);
 	return rv;
 }