mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
SUNRPC: Ensure that we free the rpc_task after cleanups are done
This patch ensures that we free the rpc_task after the cleanup callbacks are done in order to avoid a deadlock problem that can be triggered if the callback needs to wait for another workqueue item to complete. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Weston Andros Adamson <dros@netapp.com> Cc: Tejun Heo <tj@kernel.org> Cc: Bruce Fields <bfields@fieldses.org> Cc: stable@vger.kernel.org
This commit is contained in:
parent
e25fbe380c
commit
c6567ed140
1 changed files with 23 additions and 4 deletions
|
@ -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;
|
||||
|
||||
if (task->tk_flags & RPC_TASK_DYNAMIC) {
|
||||
rpc_release_calldata(task->tk_ops, task->tk_calldata);
|
||||
|
||||
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)
|
||||
|
|
Loading…
Reference in a new issue