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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-25 21:25:02 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-25 21:25:02 -0800
commit8f5f90a872c38b4e78f3cc95e8a25434b98e4db2 (patch)
tree36c50b0c97286ab89c85016f7ab281f8e843c05c /net/sunrpc/sched.c
parentc0cd2da16b431a2007ea83865f3dd1530c1643a5 (diff)
parent949db153b6466c6f7cad5a427ecea94985927311 (diff)
downloadlwn-8f5f90a872c38b4e78f3cc95e8a25434b98e4db2.tar.gz
lwn-8f5f90a872c38b4e78f3cc95e8a25434b98e4db2.zip
Merge 3.8-rc5 into staging-next
This resolves a merge issue with a iio driver, and the zram code. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/sunrpc/sched.c')
-rw-r--r--net/sunrpc/sched.c30
1 files changed, 24 insertions, 6 deletions
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index d17a704aaf5f..bfa31714581f 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -934,16 +934,35 @@ struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
return task;
}
+/*
+ * rpc_free_task - release rpc task and perform cleanups
+ *
+ * Note that we free up the rpc_task _after_ rpc_release_calldata()
+ * in order to work around a workqueue dependency issue.
+ *
+ * Tejun Heo states:
+ * "Workqueue currently considers two work items to be the same if they're
+ * on the same address and won't execute them concurrently - ie. it
+ * makes a work item which is queued again while being executed wait
+ * for the previous execution to complete.
+ *
+ * If a work function frees the work item, and then waits for an event
+ * which should be performed by another work item and *that* work item
+ * recycles the freed work item, it can create a false dependency loop.
+ * There really is no reliable way to detect this short of verifying
+ * every memory free."
+ *
+ */
static void rpc_free_task(struct rpc_task *task)
{
- const struct rpc_call_ops *tk_ops = task->tk_ops;
- void *calldata = task->tk_calldata;
+ unsigned short tk_flags = task->tk_flags;
+
+ rpc_release_calldata(task->tk_ops, task->tk_calldata);
- if (task->tk_flags & RPC_TASK_DYNAMIC) {
+ if (tk_flags & RPC_TASK_DYNAMIC) {
dprintk("RPC: %5u freeing task\n", task->tk_pid);
mempool_free(task, rpc_task_mempool);
}
- rpc_release_calldata(tk_ops, calldata);
}
static void rpc_async_release(struct work_struct *work)
@@ -953,8 +972,7 @@ static void rpc_async_release(struct work_struct *work)
static void rpc_release_resources_task(struct rpc_task *task)
{
- if (task->tk_rqstp)
- xprt_release(task);
+ xprt_release(task);
if (task->tk_msg.rpc_cred) {
put_rpccred(task->tk_msg.rpc_cred);
task->tk_msg.rpc_cred = NULL;