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@xxxxxxxxxx>
---
include/linux/sunrpc/sched.h | 2 +-
include/linux/sunrpc/xprt.h | 2 +-
net/sunrpc/clnt.c | 12 ++++++++----
net/sunrpc/sched.c | 24 +++++++++++++++---------
net/sunrpc/xprtrdma/svc_rdma_backchannel.c | 17 +++++++++--------
net/sunrpc/xprtrdma/transport.c | 26 ++++++++++++++++++--------
net/sunrpc/xprtsock.c | 17 +++++++++++------
7 files changed, 63 insertions(+), 37 deletions(-)
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 817af0b..38d4c1b 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -239,7 +239,7 @@ struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *,
void *);
void rpc_wake_up_status(struct rpc_wait_queue *, int);
void rpc_delay(struct rpc_task *, unsigned long);
-void * rpc_malloc(struct rpc_task *, size_t);
+int rpc_malloc(struct rpc_task *);
void rpc_free(void *);
int rpciod_up(void);
void rpciod_down(void);
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 6f1d41b..c01f468 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -127,7 +127,7 @@ struct rpc_xprt_ops {
void (*rpcbind)(struct rpc_task *task);
void (*set_port)(struct rpc_xprt *xprt, unsigned short port);
void (*connect)(struct rpc_xprt *xprt, struct rpc_task *task);
- void * (*buf_alloc)(struct rpc_task *task, size_t size);
+ int (*buf_alloc)(struct rpc_task *task);
void (*buf_free)(void *buffer);
int (*send_request)(struct rpc_task *task);
void (*set_retrans_timeout)(struct rpc_task *task);
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 3924e15..4dc7ed7 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1693,6 +1693,7 @@ call_allocate(struct rpc_task *task)
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
+ int status;
dprint_status(task);
@@ -1718,11 +1719,14 @@ call_allocate(struct rpc_task *task)
req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
req->rq_rcvsize <<= 2;
- req->rq_buffer = xprt->ops->buf_alloc(task,
- req->rq_callsize + req->rq_rcvsize);
- if (req->rq_buffer != NULL)
- return;
+ status = xprt->ops->buf_alloc(task);
xprt_inject_disconnect(xprt);
+ if (status == 0)
+ return;
+ if (status != -ENOMEM) {
+ rpc_exit(task, status);
+ return;
+ }
dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 9ae5885..b964d40 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);
diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
index a2a7519..124688b 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
@@ -159,29 +159,30 @@ out_unmap:
/* Server-side transport endpoint wants a whole page for its send
* buffer. The client RPC code constructs the RPC header in this
* buffer before it invokes ->send_request.
- *
- * Returns NULL if there was a temporary allocation failure.
*/
-static void *
-xprt_rdma_bc_allocate(struct rpc_task *task, size_t size)
+static int
+xprt_rdma_bc_allocate(struct rpc_task *task)
{
struct rpc_rqst *rqst = task->tk_rqstp;
struct svc_xprt *sxprt = rqst->rq_xprt->bc_xprt;
+ size_t size = rqst->rq_callsize;
struct svcxprt_rdma *rdma;
struct page *page;
rdma = container_of(sxprt, struct svcxprt_rdma, sc_xprt);
- /* Prevent an infinite loop: try to make this case work */
- if (size > PAGE_SIZE)
+ if (size > PAGE_SIZE) {
WARN_ONCE(1, "svcrdma: large bc buffer request (size %zu)\n",
size);
+ return -EINVAL;
+ }
page = alloc_page(RPCRDMA_DEF_GFP);
if (!page)
- return NULL;
+ return -ENOMEM;
- return page_address(page);
+ rqst->rq_buffer = page_address(page);
+ return 0;
}
static void
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index be95ece..daa7d4d 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -477,7 +477,15 @@ xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
}
}
-/*
+/**
+ * xprt_rdma_allocate - allocate transport resources for an RPC
+ * @task: RPC task
+ *
+ * Return values:
+ * 0: Success; rq_buffer points to RPC buffer to use
+ * ENOMEM: Out of memory, call again later
+ * EIO: A permanent error occurred, do not retry
+ *
* The RDMA allocate/free functions need the task structure as a place
* to hide the struct rpcrdma_req, which is necessary for the actual send/recv
* sequence.
@@ -486,11 +494,12 @@ xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
* (rq_send_buf and rq_rcv_buf are both part of a single contiguous buffer).
* We may register rq_rcv_buf when using reply chunks.
*/
-static void *
-xprt_rdma_allocate(struct rpc_task *task, size_t size)
+static int
+xprt_rdma_allocate(struct rpc_task *task)
{
- struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
- struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
+ struct rpc_rqst *rqst = task->tk_rqstp;
+ size_t size = rqst->rq_callsize + rqst->rq_rcvsize;
+ struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
struct rpcrdma_regbuf *rb;
struct rpcrdma_req *req;
size_t min_size;
@@ -498,7 +507,7 @@ xprt_rdma_allocate(struct rpc_task *task, size_t size)
req = rpcrdma_buffer_get(&r_xprt->rx_buf);
if (req == NULL)
- return NULL;
+ return -ENOMEM;
flags = RPCRDMA_DEF_GFP;
if (RPC_IS_SWAPPER(task))
@@ -515,7 +524,8 @@ out:
dprintk("RPC: %s: size %zd, request 0x%p\n", __func__, size, req);
req->rl_connect_cookie = 0; /* our reserved value */
req->rl_task = task;
- return req->rl_sendbuf->rg_base;
+ rqst->rq_buffer = req->rl_sendbuf->rg_base;
+ return 0;
out_rdmabuf:
min_size = r_xprt->rx_data.inline_wsize;
@@ -558,7 +568,7 @@ out_sendbuf:
out_fail:
rpcrdma_buffer_put(req);
- return NULL;
+ return -ENOMEM;
}
/*
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index bf16883..bd30b4b 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2533,23 +2533,28 @@ static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
* we allocate pages instead doing a kmalloc like rpc_malloc is because we want
* to use the server side send routines.
*/
-static void *bc_malloc(struct rpc_task *task, size_t size)
+static int bc_malloc(struct rpc_task *task)
{
+ struct rpc_rqst *rqst = task->tk_rqstp;
+ size_t size = rqst->rq_callsize;
struct page *page;
struct rpc_buffer *buf;
- WARN_ON_ONCE(size > PAGE_SIZE - sizeof(struct rpc_buffer));
- if (size > PAGE_SIZE - sizeof(struct rpc_buffer))
- return NULL;
+ if (size > PAGE_SIZE - sizeof(struct rpc_buffer)) {
+ WARN_ONCE(1, "xprtsock: large bc buffer request (size %zu)\n",
+ size);
+ return -EINVAL;
+ }
page = alloc_page(GFP_KERNEL);
if (!page)
- return NULL;
+ return -ENOMEM;
buf = page_address(page);
buf->len = PAGE_SIZE;
- return buf->data;
+ rqst->rq_buffer = buf->data;
+ return 0;
}
/*
--
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