The RPC_TASK_KILLED flag should really not be set from another context
because it can clobber data in the struct task when task->tk_flags is
changed non-atomically.
Let's therefore swap out RPC_TASK_KILLED with an atomic flag, and add
a function to set that flag and safely wake up the task.
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/lockd/clntproc.c | 4 ++--
fs/nfsd/nfs4callback.c | 4 ++--
include/linux/sunrpc/sched.h | 6 ++++--
include/trace/events/sunrpc.h | 6 +++---
net/sunrpc/clnt.c | 14 ++------------
net/sunrpc/sched.c | 28 +++++++++++++++++++++++-----
net/sunrpc/xprt.c | 4 ++++
7 files changed, 40 insertions(+), 26 deletions(-)
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index e8a004097d18..d9c32d1a20c0 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -715,7 +715,7 @@ static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
struct nlm_rqst *req = data;
u32 status = ntohl(req->a_res.status);
- if (RPC_ASSASSINATED(task))
+ if (RPC_SIGNALLED(task))
goto die;
if (task->tk_status < 0) {
@@ -783,7 +783,7 @@ static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
struct nlm_rqst *req = data;
u32 status = ntohl(req->a_res.status);
- if (RPC_ASSASSINATED(task))
+ if (RPC_SIGNALLED(task))
goto die;
if (task->tk_status < 0) {
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index d219159b98af..f7494be8dbe2 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1032,7 +1032,7 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
* the submission code will error out, so we don't need to
* handle that case here.
*/
- if (task->tk_flags & RPC_TASK_KILLED)
+ if (RPC_SIGNALLED(task))
goto need_restart;
return true;
@@ -1081,7 +1081,7 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
dprintk("%s: freed slot, new seqid=%d\n", __func__,
clp->cl_cb_session->se_cb_seq_nr);
- if (task->tk_flags & RPC_TASK_KILLED)
+ if (RPC_SIGNALLED(task))
goto need_restart;
out:
return ret;
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index ec861cd0cfe8..852ca0f2c56c 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -125,7 +125,6 @@ struct rpc_task_setup {
#define RPC_CALL_MAJORSEEN 0x0020 /* major timeout seen */
#define RPC_TASK_ROOTCREDS 0x0040 /* force root creds */
#define RPC_TASK_DYNAMIC 0x0080 /* task was kmalloc'ed */
-#define RPC_TASK_KILLED 0x0100 /* task was killed */
#define RPC_TASK_SOFT 0x0200 /* Use soft timeouts */
#define RPC_TASK_SOFTCONN 0x0400 /* Fail if can't connect */
#define RPC_TASK_SENT 0x0800 /* message was sent */
@@ -135,7 +134,6 @@ struct rpc_task_setup {
#define RPC_IS_ASYNC(t) ((t)->tk_flags & RPC_TASK_ASYNC)
#define RPC_IS_SWAPPER(t) ((t)->tk_flags & RPC_TASK_SWAPPER)
-#define RPC_ASSASSINATED(t) ((t)->tk_flags & RPC_TASK_KILLED)
#define RPC_IS_SOFT(t) ((t)->tk_flags & (RPC_TASK_SOFT|RPC_TASK_TIMEOUT))
#define RPC_IS_SOFTCONN(t) ((t)->tk_flags & RPC_TASK_SOFTCONN)
#define RPC_WAS_SENT(t) ((t)->tk_flags & RPC_TASK_SENT)
@@ -146,6 +144,7 @@ struct rpc_task_setup {
#define RPC_TASK_NEED_XMIT 3
#define RPC_TASK_NEED_RECV 4
#define RPC_TASK_MSG_PIN_WAIT 5
+#define RPC_TASK_SIGNALLED 6
#define RPC_IS_RUNNING(t) test_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
#define rpc_set_running(t) set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
@@ -169,6 +168,8 @@ struct rpc_task_setup {
#define RPC_IS_ACTIVATED(t) test_bit(RPC_TASK_ACTIVE, &(t)->tk_runstate)
+#define RPC_SIGNALLED(t) test_bit(RPC_TASK_SIGNALLED, &(t)->tk_runstate)
+
/*
* Task priorities.
* Note: if you change these, you must also change
@@ -217,6 +218,7 @@ struct rpc_task *rpc_run_task(const struct rpc_task_setup *);
struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req);
void rpc_put_task(struct rpc_task *);
void rpc_put_task_async(struct rpc_task *);
+void rpc_signal_task(struct rpc_task *);
void rpc_exit_task(struct rpc_task *);
void rpc_exit(struct rpc_task *, int);
void rpc_release_calldata(const struct rpc_call_ops *, void *);
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 7e899e635d33..5e3b77d9daa7 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -82,7 +82,6 @@ TRACE_DEFINE_ENUM(RPC_TASK_SWAPPER);
TRACE_DEFINE_ENUM(RPC_CALL_MAJORSEEN);
TRACE_DEFINE_ENUM(RPC_TASK_ROOTCREDS);
TRACE_DEFINE_ENUM(RPC_TASK_DYNAMIC);
-TRACE_DEFINE_ENUM(RPC_TASK_KILLED);
TRACE_DEFINE_ENUM(RPC_TASK_SOFT);
TRACE_DEFINE_ENUM(RPC_TASK_SOFTCONN);
TRACE_DEFINE_ENUM(RPC_TASK_SENT);
@@ -97,7 +96,6 @@ TRACE_DEFINE_ENUM(RPC_TASK_NO_RETRANS_TIMEOUT);
{ RPC_CALL_MAJORSEEN, "MAJORSEEN" }, \
{ RPC_TASK_ROOTCREDS, "ROOTCREDS" }, \
{ RPC_TASK_DYNAMIC, "DYNAMIC" }, \
- { RPC_TASK_KILLED, "KILLED" }, \
{ RPC_TASK_SOFT, "SOFT" }, \
{ RPC_TASK_SOFTCONN, "SOFTCONN" }, \
{ RPC_TASK_SENT, "SENT" }, \
@@ -111,6 +109,7 @@ TRACE_DEFINE_ENUM(RPC_TASK_ACTIVE);
TRACE_DEFINE_ENUM(RPC_TASK_NEED_XMIT);
TRACE_DEFINE_ENUM(RPC_TASK_NEED_RECV);
TRACE_DEFINE_ENUM(RPC_TASK_MSG_PIN_WAIT);
+TRACE_DEFINE_ENUM(RPC_TASK_SIGNALLED);
#define rpc_show_runstate(flags) \
__print_flags(flags, "|", \
@@ -119,7 +118,8 @@ TRACE_DEFINE_ENUM(RPC_TASK_MSG_PIN_WAIT);
{ (1UL << RPC_TASK_ACTIVE), "ACTIVE" }, \
{ (1UL << RPC_TASK_NEED_XMIT), "NEED_XMIT" }, \
{ (1UL << RPC_TASK_NEED_RECV), "NEED_RECV" }, \
- { (1UL << RPC_TASK_MSG_PIN_WAIT), "MSG_PIN_WAIT" })
+ { (1UL << RPC_TASK_MSG_PIN_WAIT), "MSG_PIN_WAIT" }, \
+ { (1UL << RPC_TASK_SIGNALLED), "SIGNALLED" })
DECLARE_EVENT_CLASS(rpc_task_running,
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 187d10443a15..30f5995c6a68 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -827,14 +827,8 @@ void rpc_killall_tasks(struct rpc_clnt *clnt)
* Spin lock all_tasks to prevent changes...
*/
spin_lock(&clnt->cl_lock);
- list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
- if (!RPC_IS_ACTIVATED(rovr))
- continue;
- if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
- rovr->tk_flags |= RPC_TASK_KILLED;
- rpc_exit(rovr, -EIO);
- }
- }
+ list_for_each_entry(rovr, &clnt->cl_tasks, tk_task)
+ rpc_signal_task(rovr);
spin_unlock(&clnt->cl_lock);
}
EXPORT_SYMBOL_GPL(rpc_killall_tasks);
@@ -1477,8 +1471,6 @@ EXPORT_SYMBOL_GPL(rpc_force_rebind);
int
rpc_restart_call_prepare(struct rpc_task *task)
{
- if (RPC_ASSASSINATED(task))
- return 0;
task->tk_action = call_start;
task->tk_status = 0;
if (task->tk_ops->rpc_call_prepare != NULL)
@@ -1494,8 +1486,6 @@ EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
int
rpc_restart_call(struct rpc_task *task)
{
- if (RPC_ASSASSINATED(task))
- return 0;
task->tk_action = call_start;
task->tk_status = 0;
return 1;
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 28956c70100a..3d6cb91ba598 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -759,8 +759,7 @@ static void
rpc_reset_task_statistics(struct rpc_task *task)
{
task->tk_timeouts = 0;
- task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_KILLED|RPC_TASK_SENT);
-
+ task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_SENT);
rpc_init_task_statistics(task);
}
@@ -773,7 +772,6 @@ void rpc_exit_task(struct rpc_task *task)
if (task->tk_ops->rpc_call_done != NULL) {
task->tk_ops->rpc_call_done(task, task->tk_calldata);
if (task->tk_action != NULL) {
- WARN_ON(RPC_ASSASSINATED(task));
/* Always release the RPC slot and buffer memory */
xprt_release(task);
rpc_reset_task_statistics(task);
@@ -781,6 +779,19 @@ void rpc_exit_task(struct rpc_task *task)
}
}
+void rpc_signal_task(struct rpc_task *task)
+{
+ struct rpc_wait_queue *queue;
+
+ if (!RPC_IS_ACTIVATED(task))
+ return;
+ set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate);
+ smp_mb__after_atomic();
+ queue = READ_ONCE(task->tk_waitqueue);
+ if (queue)
+ rpc_wake_up_queued_task_set_status(queue, task, -ERESTARTSYS);
+}
+
void rpc_exit(struct rpc_task *task, int status)
{
task->tk_status = status;
@@ -836,6 +847,13 @@ static void __rpc_execute(struct rpc_task *task)
*/
if (!RPC_IS_QUEUED(task))
continue;
+
+ /*
+ * Signalled tasks should exit rather than sleep.
+ */
+ if (RPC_SIGNALLED(task))
+ rpc_exit(task, -ERESTARTSYS);
+
/*
* The queue->lock protects against races with
* rpc_make_runnable().
@@ -861,7 +879,7 @@ static void __rpc_execute(struct rpc_task *task)
status = out_of_line_wait_on_bit(&task->tk_runstate,
RPC_TASK_QUEUED, rpc_wait_bit_killable,
TASK_KILLABLE);
- if (status == -ERESTARTSYS) {
+ if (status < 0) {
/*
* When a sync task receives a signal, it exits with
* -ERESTARTSYS. In order to catch any callbacks that
@@ -869,7 +887,7 @@ static void __rpc_execute(struct rpc_task *task)
* break the loop here, but go around once more.
*/
dprintk("RPC: %5u got signal\n", task->tk_pid);
- task->tk_flags |= RPC_TASK_KILLED;
+ set_bit(RPC_TASK_SIGNALLED, &task->tk_runstate);
rpc_exit(task, -ERESTARTSYS);
}
dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index d7117d241460..3a4156cb0134 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1337,6 +1337,10 @@ xprt_request_transmit(struct rpc_rqst *req, struct rpc_task *snd_task)
if (status < 0)
goto out_dequeue;
}
+ if (RPC_SIGNALLED(task)) {
+ status = -ERESTARTSYS;
+ goto out_dequeue;
+ }
}
/*
--
2.20.1
