[dpdk-dev] [PATCH V4 1/9] bus: introduce hotplug failure handler

[Jeff Guo <jia.guo@intel.com>]

When a hardware device is removed physically or the software disables
it, the hotplug occur. App need to call ether dev API to detach the device,
to unplug the device at the bus level and make access to the device
invalid. But the removal of the device from the software lists is not going
to be instantaneous, at this time if the data path still read/write the
device, it will cause MMIO error and result of the app crash out. So a
hotplug failure handle mechanism need to be used to guaranty app will not
crash out when hot unplug device.

To handle device hot plug failure is a bus-specific behavior, this patch
introduces a bus ops so that each kind of bus can implement its own logic.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 lib/librte_eal/common/include/rte_bus.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index eb9eded..3642aeb 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -168,6 +168,19 @@ typedef int (*rte_bus_unplug_t)(struct rte_device *dev);
 typedef int (*rte_bus_parse_t)(const char *name, void *addr);
 
 /**
+ * Implementation a specific hot plug handler, which is responsible
+ * for handle the failure when hot remove the device, guaranty the system
+ * would not crash in the case.
+ * @param dev
+ *	Pointer of the device structure.
+ *
+ * @return
+ *	0 on success.
+ *	!0 on error.
+ */
+typedef int (*rte_bus_hotplug_handler_t)(struct rte_device *dev);
+
+/**
  * Bus scan policies
  */
 enum rte_bus_scan_mode {
@@ -211,6 +224,8 @@ struct rte_bus {
 	rte_bus_parse_t parse;       /**< Parse a device name */
 	struct rte_bus_conf conf;    /**< Bus configuration */
 	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
+	rte_bus_hotplug_handler_t hotplug_handler;
+						/**< handle hot plug on bus */
 };
 
 /**
-- 
2.7.4