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authorChuck Lever <chuck.lever@oracle.com>2016-09-15 10:55:20 -0400
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2016-09-19 13:08:37 -0400
commit5fe6eaa1f9a00b9a5927e3b791ecad2f3eaab130 (patch)
tree3b5b516ef941eb91452458260d08b3473491913c /net/sunrpc/sched.c
parentb9c5bc03be6aae41990efd09f83cf70a89ac9f4b (diff)
SUNRPC: Generalize the RPC buffer allocation API
xprtrdma needs to allocate the Call and Reply buffers separately. TBH, the reliance on using a single buffer for the pair of XDR buffers is transport implementation-specific. Transports that want to allocate separate Call and Reply buffers will ignore the "size" argument anyway. Don't bother passing it. The buf_alloc method can't return two pointers. Instead, make the method's return value an error code, and set the rq_buffer pointer in the method itself. This gives call_allocate an opportunity to terminate an RPC instead of looping forever when a permanent problem occurs. If a request is just bogus, or the transport is in a state where it can't allocate resources for any request, there needs to be a way to kill the RPC right there and not loop. This immediately fixes a rare problem in the backchannel send path, which loops if the server happens to send a CB request whose call+reply size is larger than a page (which it shouldn't do yet). One more issue: looks like xprt_inject_disconnect was incorrectly placed in the failure path in call_allocate. It needs to be in the success path, as it is for other call-sites. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net/sunrpc/sched.c')
-rw-r--r--net/sunrpc/sched.c24
1 files changed, 15 insertions, 9 deletions
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 9ae588511aaf..b964d40b259b 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -849,14 +849,17 @@ static void rpc_async_schedule(struct work_struct *work)
}
/**
- * rpc_malloc - allocate an RPC buffer
- * @task: RPC task that will use this buffer
- * @size: requested byte size
+ * rpc_malloc - allocate RPC buffer resources
+ * @task: RPC task
+ *
+ * A single memory region is allocated, which is split between the
+ * RPC call and RPC reply that this task is being used for. When
+ * this RPC is retired, the memory is released by calling rpc_free.
*
* To prevent rpciod from hanging, this allocator never sleeps,
- * returning NULL and suppressing warning if the request cannot be serviced
- * immediately.
- * The caller can arrange to sleep in a way that is safe for rpciod.
+ * returning -ENOMEM and suppressing warning 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,
@@ -865,8 +868,10 @@ static void rpc_async_schedule(struct work_struct *work)
* In order to avoid memory starvation triggering more writebacks of
* NFS requests, we avoid using GFP_KERNEL.
*/
-void *rpc_malloc(struct rpc_task *task, size_t size)
+int rpc_malloc(struct rpc_task *task)
{
+ struct rpc_rqst *rqst = task->tk_rqstp;
+ size_t size = rqst->rq_callsize + rqst->rq_rcvsize;
struct rpc_buffer *buf;
gfp_t gfp = GFP_NOIO | __GFP_NOWARN;
@@ -880,12 +885,13 @@ void *rpc_malloc(struct rpc_task *task, size_t size)
buf = kmalloc(size, gfp);
if (!buf)
- return NULL;
+ return -ENOMEM;
buf->len = size;
dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
task->tk_pid, size, buf);
- return &buf->data;
+ rqst->rq_buffer = buf->data;
+ return 0;
}
EXPORT_SYMBOL_GPL(rpc_malloc);