NFS: blocklayout pipe creation per network namespace context introduced

This patch implements blocklayout pipe creation and registration per each
existent network namespace.
This was achived by registering NFS per-net operations, responsible for
blocklayout pipe allocation/register and unregister/destruction instead of
initialization and destruction of static "bl_device_pipe" pipe (this one was
removed).
Note, than pointer to network blocklayout pipe is stored in per-net "nfs_net"
structure, because allocating of one more per-net structure for blocklayout
module looks redundant.
This patch also changes dev_remove() function prototype (and all it's callers,
where it' requied) by adding network namespace pointer parameter, which is used
to discover proper blocklayout pipe for rpc_queue_upcall() call.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/blocklayout/blocklayoutdm.c b/fs/nfs/blocklayout/blocklayoutdm.c
index 631f254..970490f 100644
--- a/fs/nfs/blocklayout/blocklayoutdm.c
+++ b/fs/nfs/blocklayout/blocklayoutdm.c
@@ -38,7 +38,7 @@
 
 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
 
-static void dev_remove(dev_t dev)
+static void dev_remove(struct net *net, dev_t dev)
 {
 	struct rpc_pipe_msg msg;
 	struct bl_dev_msg bl_umount_request;
@@ -48,6 +48,7 @@
 	};
 	uint8_t *dataptr;
 	DECLARE_WAITQUEUE(wq, current);
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
 
 	dprintk("Entering %s\n", __func__);
 
@@ -66,7 +67,7 @@
 	msg.len = sizeof(bl_msg) + bl_msg.totallen;
 
 	add_wait_queue(&bl_wq, &wq);
-	if (rpc_queue_upcall(bl_device_pipe, &msg) < 0) {
+	if (rpc_queue_upcall(nn->bl_device_pipe, &msg) < 0) {
 		remove_wait_queue(&bl_wq, &wq);
 		goto out;
 	}
@@ -93,7 +94,7 @@
 		printk(KERN_ERR "%s nfs4_blkdev_put returns %d\n",
 				__func__, rv);
 
-	dev_remove(bdev->bm_mdev->bd_dev);
+	dev_remove(bdev->net, bdev->bm_mdev->bd_dev);
 }
 
 void bl_free_block_dev(struct pnfs_block_dev *bdev)