padata: ensure padata_do_serial() runs on the correct CPU
If the algorithm we're parallelizing is asynchronous we might change
CPUs between padata_do_parallel() and padata_do_serial(). However, we
don't expect this to happen as we need to enqueue the padata object into
the per-cpu reorder queue we took it from, i.e. the same-cpu's parallel
queue.
Ensure we're not switching CPUs for a given padata object by tracking
the CPU within the padata object. If the serial callback gets called on
the wrong CPU, defer invoking padata_reorder() via a kernel worker on
the CPU we're expected to run on.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/linux/padata.h b/include/linux/padata.h
index 5c0175b..5d13d25 100644
--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -37,6 +37,7 @@
* @list: List entry, to attach to the padata lists.
* @pd: Pointer to the internal control structure.
* @cb_cpu: Callback cpu for serializatioon.
+ * @cpu: Cpu for parallelization.
* @seq_nr: Sequence number of the parallelized data object.
* @info: Used to pass information from the parallel to the serial function.
* @parallel: Parallel execution function.
@@ -46,6 +47,7 @@ struct padata_priv {
struct list_head list;
struct parallel_data *pd;
int cb_cpu;
+ int cpu;
int info;
void (*parallel)(struct padata_priv *padata);
void (*serial)(struct padata_priv *padata);