SUNRPC: Fix pointer arithmetic bug recently introduced in rpc_malloc/free
Use a cleaner method to find the size of an rpc_buffer. This actually
works on x86-64!
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 9901451..b28a0b0 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -736,6 +736,11 @@
__rpc_execute(container_of(work, struct rpc_task, u.tk_work));
}
+struct rpc_buffer {
+ size_t len;
+ char data[];
+};
+
/**
* rpc_malloc - allocate an RPC buffer
* @task: RPC task that will use this buffer
@@ -754,18 +759,18 @@
*/
void *rpc_malloc(struct rpc_task *task, size_t size)
{
- size_t *buf;
+ struct rpc_buffer *buf;
gfp_t gfp = RPC_IS_SWAPPER(task) ? GFP_ATOMIC : GFP_NOWAIT;
- size += sizeof(size_t);
+ size += sizeof(struct rpc_buffer);
if (size <= RPC_BUFFER_MAXSIZE)
buf = mempool_alloc(rpc_buffer_mempool, gfp);
else
buf = kmalloc(size, gfp);
- *buf = size;
+ buf->len = size;
dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
task->tk_pid, size, buf);
- return ++buf;
+ return &buf->data;
}
/**
@@ -775,15 +780,18 @@
*/
void rpc_free(void *buffer)
{
- size_t size, *buf = buffer;
+ size_t size;
+ struct rpc_buffer *buf;
if (!buffer)
return;
- size = *buf;
- buf--;
+
+ buf = container_of(buffer, struct rpc_buffer, data);
+ size = buf->len;
dprintk("RPC: freeing buffer of size %zu at %p\n",
size, buf);
+
if (size <= RPC_BUFFER_MAXSIZE)
mempool_free(buf, rpc_buffer_mempool);
else