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Subject[PATCH 21/22] Staging: hv: Introduce a function to map channel properties onto block device info
Date
In preparation for removing the IDE details from the block driver, implement
a function that maps channel properties to block device information.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
---
drivers/staging/hv/storvsc.c | 68 ++++++++++++++++++++++++++++++++++++++
drivers/staging/hv/storvsc_api.h | 10 +++++
2 files changed, 78 insertions(+), 0 deletions(-)
diff --git a/drivers/staging/hv/storvsc.c b/drivers/staging/hv/storvsc.c
index d7ce393..e2b3410 100644
--- a/drivers/staging/hv/storvsc.c
+++ b/drivers/staging/hv/storvsc.c
@@ -17,6 +17,8 @@
* Authors:
* Haiyang Zhang <haiyangz@microsoft.com>
* Hank Janssen <hjanssen@microsoft.com>
+ *
+ * 4/3/2011: K. Y. Srinivasan - Significant restructuring and cleanup.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
@@ -593,6 +595,72 @@ int stor_vsc_on_io_request(struct hv_device *device,
}

/*
+ * The channel properties uniquely specify how the device is to be
+ * presented to the guest. Map this information for use by the block
+ * driver. For Linux guests on Hyper-V, we emulate a scsi HBA in the guest
+ * (storvsc_drv) and so scsi devices in the guest are handled by
+ * native upper level Linux drivers. Consequently, Hyper-V
+ * block driver, while being a generic block driver, presently does not
+ * deal with anything other than devices that would need to be presented
+ * to the guest as an IDE disk.
+ *
+ * This function maps the channel properties as embedded in the input
+ * parameter device_info onto information necessary to register the
+ * corresponding block device.
+ *
+ * Currently, there is no way to stop the emulation of the block device
+ * on the host side. And so, to prevent the native IDE drivers in Linux
+ * from taking over these devices (to be managedby Hyper-V block
+ * driver), we will take over if need be the major of the IDE controllers.
+ *
+ */
+
+int stor_vsc_get_major_info(struct storvsc_device_info *device_info,
+ struct storvsc_major_info *major_info)
+{
+ static bool ide0_registered;
+ static bool ide1_registered;
+
+ /*
+ * For now we only support IDE disks.
+ */
+ major_info->devname = "ide";
+ major_info->diskname = "hd";
+
+ if (device_info->path_id) {
+ major_info->major = 22;
+ if (!ide1_registered)
+ major_info->do_register = true;
+ else {
+ major_info->do_register = false;
+ ide1_registered = true;
+ }
+ if (device_info->target_id)
+ major_info->index = 3;
+ else
+ major_info->index = 2;
+
+ return 0;
+ } else {
+ major_info->major = 3;
+ if (!ide0_registered)
+ major_info->do_register = true;
+ else {
+ major_info->do_register = false;
+ ide0_registered = true;
+ }
+ if (device_info->target_id)
+ major_info->index = 1;
+ else
+ major_info->index = 0;
+
+ return 0;
+ }
+
+ return -ENODEV;
+}
+
+/*
* stor_vsc_on_cleanup - Perform any cleanup when the driver is removed
*/
void stor_vsc_on_cleanup(struct hv_driver *driver)
diff --git a/drivers/staging/hv/storvsc_api.h b/drivers/staging/hv/storvsc_api.h
index d7db949..c98139c 100644
--- a/drivers/staging/hv/storvsc_api.h
+++ b/drivers/staging/hv/storvsc_api.h
@@ -92,6 +92,14 @@ struct storvsc_device_info {
unsigned char target_id;
};

+struct storvsc_major_info {
+ int major;
+ int index;
+ bool do_register;
+ char *devname;
+ char *diskname;
+};
+
/* A storvsc device is a device object that contains a vmbus channel */
struct storvsc_device {
struct hv_device *device;
@@ -155,5 +163,7 @@ int stor_vsc_on_io_request(struct hv_device *device,
struct hv_storvsc_request *request);
void stor_vsc_on_cleanup(struct hv_driver *driver);

+int stor_vsc_get_major_info(struct storvsc_device_info *device_info,
+ struct storvsc_major_info *major_info);

#endif /* _STORVSC_API_H_ */
--
1.7.4.1


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