Merge branches 'armv7', 'at91', 'misc' and 'omap' into devel

[~andy/linux] / net / sunrpc / sched.c

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index ca56b8e9b64958f25f2087b0521d87168158d953..4a53e94f813415ac757f5180bf0d20a3323ba2d2 100644 (file)
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -4,7 +4,7 @@
  * Scheduling for synchronous and asynchronous RPC requests.
  *
  * Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
- * 
+ *
  * TCP NFS related read + write fixes
  * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
  */
@@ -307,7 +307,7 @@ EXPORT_SYMBOL(__rpc_wait_for_completion_task);
 /*
  * Make an RPC task runnable.
  *
- * Note: If the task is ASYNC, this must be called with 
+ * Note: If the task is ASYNC, this must be called with
  * the spinlock held to protect the wait queue operation.
  */
 static void rpc_make_runnable(struct rpc_task *task)
@@ -648,8 +648,8 @@ static void __rpc_execute(struct rpc_task *task)
                if (RPC_DO_CALLBACK(task)) {
                        /* Define a callback save pointer */
                        void (*save_callback)(struct rpc_task *);
-       
-                       /* 
+
+                       /*
                         * If a callback exists, save it, reset it,
                         * call it.
                         * The save is needed to stop from resetting
@@ -741,50 +741,53 @@ static void rpc_async_schedule(struct work_struct *work)
  * @task: RPC task that will use this buffer
  * @size: requested byte size
  *
- * We try to ensure that some NFS reads and writes can always proceed
- * by using a mempool when allocating 'small' buffers.
+ * To prevent rpciod from hanging, this allocator never sleeps,
+ * returning NULL if the request cannot be serviced immediately.
+ * The caller can arrange to sleep in a way that is safe for rpciod.
+ *
+ * Most requests are 'small' (under 2KiB) and can be serviced from a
+ * mempool, ensuring that NFS reads and writes can always proceed,
+ * and that there is good locality of reference for these buffers.
+ *
  * In order to avoid memory starvation triggering more writebacks of
- * NFS requests, we use GFP_NOFS rather than GFP_KERNEL.
+ * NFS requests, we avoid using GFP_KERNEL.
  */
-void * rpc_malloc(struct rpc_task *task, size_t size)
+void *rpc_malloc(struct rpc_task *task, size_t size)
 {
-       struct rpc_rqst *req = task->tk_rqstp;
-       gfp_t   gfp;
+       size_t *buf;
+       gfp_t gfp = RPC_IS_SWAPPER(task) ? GFP_ATOMIC : GFP_NOWAIT;
 
-       if (task->tk_flags & RPC_TASK_SWAPPER)
-               gfp = GFP_ATOMIC;
+       size += sizeof(size_t);
+       if (size <= RPC_BUFFER_MAXSIZE)
+               buf = mempool_alloc(rpc_buffer_mempool, gfp);
        else
-               gfp = GFP_NOFS;
-
-       if (size > RPC_BUFFER_MAXSIZE) {
-               req->rq_buffer = kmalloc(size, gfp);
-               if (req->rq_buffer)
-                       req->rq_bufsize = size;
-       } else {
-               req->rq_buffer = mempool_alloc(rpc_buffer_mempool, gfp);
-               if (req->rq_buffer)
-                       req->rq_bufsize = RPC_BUFFER_MAXSIZE;
-       }
-       return req->rq_buffer;
+               buf = kmalloc(size, gfp);
+       *buf = size;
+       dprintk("RPC: %5u allocated buffer of size %u at %p\n",
+                       task->tk_pid, size, buf);
+       return (void *) ++buf;
 }
 
 /**
  * rpc_free - free buffer allocated via rpc_malloc
- * @task: RPC task with a buffer to be freed
+ * @buffer: buffer to free
  *
  */
-void rpc_free(struct rpc_task *task)
+void rpc_free(void *buffer)
 {
-       struct rpc_rqst *req = task->tk_rqstp;
+       size_t size, *buf = (size_t *) buffer;
 
-       if (req->rq_buffer) {
-               if (req->rq_bufsize == RPC_BUFFER_MAXSIZE)
-                       mempool_free(req->rq_buffer, rpc_buffer_mempool);
-               else
-                       kfree(req->rq_buffer);
-               req->rq_buffer = NULL;
-               req->rq_bufsize = 0;
-       }
+       if (!buffer)
+               return;
+       size = *buf;
+       buf--;
+
+       dprintk("RPC:       freeing buffer of size %u at %p\n",
+                       size, buf);
+       if (size <= RPC_BUFFER_MAXSIZE)
+               mempool_free(buf, rpc_buffer_mempool);
+       else
+               kfree(buf);
 }
 
 /*