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authorRicardo Labiaga <Ricardo.Labiaga@netapp.com>2009-04-01 09:23:00 -0400
committerBenny Halevy <bhalevy@panasas.com>2009-06-17 13:06:14 -0700
commitfb7a0b9addbdbbb13b7bc02abf55ee524ea19ce1 (patch)
tree58f623e78f74c590e20b48f95897c5857d39728f /include/linux/sunrpc
parentf9acac1a4710ce88871f1ae323fc91c1cb6e9d52 (diff)
nfs41: New backchannel helper routines
This patch introduces support to setup the callback xprt on the client side. It allocates/ destroys the preallocated memory structures used to process backchannel requests. At setup time, xprt_setup_backchannel() is invoked to allocate one or more rpc_rqst structures and substructures. This ensures that they are available when an RPC callback arrives. The rpc_rqst structures are maintained in a linked list attached to the rpc_xprt structure. We keep track of the number of allocations so that they can be correctly removed when the channel is destroyed. When an RPC callback arrives, xprt_alloc_bc_request() is invoked to obtain a preallocated rpc_rqst structure. An rpc_xprt structure is returned, and its RPC_BC_PREALLOC_IN_USE bit is set in rpc_xprt->bc_flags. The structure is removed from the the list since it is now in use, and it will be later added back when its user is done with it. After the RPC callback replies, the rpc_rqst structure is returned by invoking xprt_free_bc_request(). This clears the RPC_BC_PREALLOC_IN_USE bit and adds it back to the list, allowing it to be reused by a subsequent RPC callback request. To be consistent with the reception of RPC messages, the backchannel requests should be placed into the 'struct rpc_rqst' rq_rcv_buf, which is then in turn copied to the 'struct rpc_rqst' rq_private_buf. [nfs41: Preallocate rpc_rqst receive buffer for handling callbacks] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Update copyright notice and explain page allocation] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Diffstat (limited to 'include/linux/sunrpc')
-rw-r--r--include/linux/sunrpc/xprt.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 703af7ebf6c..beae030e80b 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -183,6 +183,7 @@ struct rpc_xprt {
#if defined(CONFIG_NFS_V4_1)
struct svc_serv *bc_serv; /* The RPC service which will */
/* process the callback */
+ unsigned int bc_alloc_count; /* Total number of preallocs */
spinlock_t bc_pa_lock; /* Protects the preallocated
* items */
struct list_head bc_pa_list; /* List of preallocated