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Subject[PATCH v1 2/8] dmaengine: rebalance DMA channels when CPU hotplug happens
Date
Rebalance DMA channels when CPU hotplug happens to correctly update
DMA channel reference count.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
drivers/dma/dmaengine.c | 22 ++++++++++++++++++++++
1 files changed, 22 insertions(+), 0 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 5b6ad58..198d891 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -49,6 +49,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
+#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/hardirq.h>
@@ -1008,8 +1009,29 @@ void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
}
EXPORT_SYMBOL_GPL(dma_run_dependencies);

+static int __cpuinit
+hotcpu_rebalance(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+ switch (action) {
+ case CPU_ONLINE:
+ case CPU_POST_DEAD:
+ mutex_lock(&dma_list_mutex);
+ dma_channel_rebalance();
+ mutex_unlock(&dma_list_mutex);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __refdata dma_cpu_notifier = {
+ .notifier_call = hotcpu_rebalance,
+};
+
+
static int __init dma_bus_init(void)
{
+ register_hotcpu_notifier(&dma_cpu_notifier);
return class_register(&dma_devclass);
}
arch_initcall(dma_bus_init);
--
1.7.5.4


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