greybus: pass appropriate type to create function

Based on a patch from Alex Elder <elder@linaro.org>.

Alex's original description:

Every descriptor in a manifest is interpreted by greybus_new_module().
We call a function to do initialization based on descriptor's type.

Since we know the type of the descriptor at that point, we can pass
to the called function the actual sub-type it needs (i.e., the union
member associated with the type).  This allows those functions to
be slightly simplified, and more focused.

Also change some size variables to have size_t type, and simplify a
few spots further by using sizeof(object) in place of sizeof(type).

diff --git a/drivers/staging/greybus/core.c b/drivers/staging/greybus/core.c
index f239b96..647bc5b 100644 (file)
--- a/drivers/staging/greybus/core.c
+++ b/drivers/staging/greybus/core.c
@@ -237,53 +237,50 @@ static const struct greybus_module_id fake_gb_id = {
 };
 
 static int create_function(struct greybus_device *gdev,
-                          struct greybus_descriptor *desc, int desc_size)
+                          struct greybus_descriptor_function *function,
+                          size_t desc_size)
 {
-       int header_size = sizeof(struct greybus_descriptor_function);
-
-       if (desc_size != header_size) {
-               dev_err(gdev->dev.parent, "invalid function header size %d\n",
+       if (desc_size != sizeof(*function)) {
+               dev_err(gdev->dev.parent, "invalid function header size %zu\n",
                        desc_size);
                return -EINVAL;
        }
-       memcpy(&gdev->function, &desc->function, header_size);
+       memcpy(&gdev->function, function, desc_size);
        return 0;
 }
 
 static int create_module_id(struct greybus_device *gdev,
-                           struct greybus_descriptor *desc, int desc_size)
+                           struct greybus_descriptor_module_id *module_id,
+                           size_t desc_size)
 {
-       int header_size = sizeof(struct greybus_descriptor_module_id);
-
-       if (desc_size != header_size) {
-               dev_err(gdev->dev.parent, "invalid module header size %d\n",
+       if (desc_size != sizeof(*module_id)) {
+               dev_err(gdev->dev.parent, "invalid module header size %zu\n",
                        desc_size);
                return -EINVAL;
        }
-       memcpy(&gdev->module_id, &desc->module_id, header_size);
+       memcpy(&gdev->module_id, module_id, desc_size);
        return 0;
 }
 
 static int create_serial_number(struct greybus_device *gdev,
-                               struct greybus_descriptor *desc, int desc_size)
+                               struct greybus_descriptor_serial_number *serial_num,
+                               size_t desc_size)
 {
-       int header_size = sizeof(struct greybus_descriptor_serial_number);
-
-       if (desc_size != header_size) {
-               dev_err(gdev->dev.parent, "invalid serial number header size %d\n",
+       if (desc_size != sizeof(*serial_num)) {
+               dev_err(gdev->dev.parent, "invalid serial number header size %zu\n",
                        desc_size);
                return -EINVAL;
        }
-       memcpy(&gdev->serial_number, &desc->serial_number, header_size);
+       memcpy(&gdev->serial_number, serial_num, desc_size);
        return 0;
 }
 
 static int create_string(struct greybus_device *gdev,
-                        struct greybus_descriptor *desc, int desc_size)
+                        struct greybus_descriptor_string *string,
+                        size_t desc_size)
 {
        int string_size;
-       struct gdev_string *string;
-       int header_size  = sizeof(struct greybus_descriptor_string);
+       struct gdev_string *gdev_string;
 
        if ((gdev->num_strings + 1) >= MAX_STRINGS_PER_MODULE) {
                dev_err(gdev->dev.parent,
@@ -291,53 +288,53 @@ static int create_string(struct greybus_device *gdev,
                return -EINVAL;
        }
 
-       if (desc_size < header_size) {
-               dev_err(gdev->dev.parent, "invalid string header size %d\n",
+       if (desc_size < sizeof(*string)) {
+               dev_err(gdev->dev.parent, "invalid string header size %zu\n",
                        desc_size);
                return -EINVAL;
        }
 
-       string_size = le16_to_cpu(desc->string.length);
-       string = kzalloc(sizeof(*string) + string_size + 1, GFP_KERNEL);
-       if (!string)
+       string_size = le16_to_cpu(string->length);
+       gdev_string = kzalloc(sizeof(*gdev_string) + string_size + 1, GFP_KERNEL);
+       if (!gdev_string)
                return -ENOMEM;
 
-       string->length = string_size;
-       string->id = desc->string.id;
-       memcpy(&string->string, &desc->string.string, string_size);
+       gdev_string->length = string_size;
+       gdev_string->id = string->id;
+       memcpy(&gdev_string->string, &string->string, string_size);
 
-       gdev->string[gdev->num_strings] = string;
+       gdev->string[gdev->num_strings] = gdev_string;
        gdev->num_strings++;
 
        return 0;
 }
 
 static int create_cport(struct greybus_device *gdev,
-                       struct greybus_descriptor *desc, int desc_size)
+                       struct greybus_descriptor_cport *cport,
+                       size_t desc_size)
 {
-       struct gdev_cport *cport;
-       int header_size = sizeof(struct greybus_descriptor_cport);
+       struct gdev_cport *gdev_cport;
 
        if ((gdev->num_cports + 1) >= MAX_CPORTS_PER_MODULE) {
                dev_err(gdev->dev.parent, "too many cports for this module!\n");
                return -EINVAL;
        }
 
-       if (desc_size != header_size) {
+       if (desc_size != sizeof(*cport)) {
                dev_err(gdev->dev.parent,
-                       "invalid serial number header size %d\n", desc_size);
+                       "invalid serial number header size %zu\n", desc_size);
                return -EINVAL;
        }
 
-       cport = kzalloc(sizeof(*cport), GFP_KERNEL);
-       if (!cport)
+       gdev_cport = kzalloc(sizeof(*gdev_cport), GFP_KERNEL);
+       if (!gdev_cport)
                return -ENOMEM;
 
-       cport->number = le16_to_cpu(desc->cport.number);
-       cport->size = le16_to_cpu(desc->cport.size);
-       cport->speed = desc->cport.speed;
+       gdev_cport->number = le16_to_cpu(cport->number);
+       gdev_cport->size = le16_to_cpu(cport->size);
+       gdev_cport->speed = cport->speed;
 
-       gdev->cport[gdev->num_cports] = cport;
+       gdev->cport[gdev->num_cports] = gdev_cport;
        gdev->num_cports++;
 
        return 0;
@@ -412,23 +409,27 @@ struct greybus_device *greybus_new_module(struct device *parent,
 
                switch (le16_to_cpu(desc->header.type)) {
                case GREYBUS_TYPE_FUNCTION:
-                       retval = create_function(gdev, desc, data_size);
+                       retval = create_function(gdev, &desc->function,
+                                                data_size);
                        break;
 
                case GREYBUS_TYPE_MODULE_ID:
-                       retval = create_module_id(gdev, desc, data_size);
+                       retval = create_module_id(gdev, &desc->module_id,
+                                                 data_size);
                        break;
 
                case GREYBUS_TYPE_SERIAL_NUMBER:
-                       retval = create_serial_number(gdev, desc, data_size);
+                       retval = create_serial_number(gdev,
+                                                     &desc->serial_number,
+                                                     data_size);
                        break;
 
                case GREYBUS_TYPE_STRING:
-                       retval = create_string(gdev, desc, data_size);
+                       retval = create_string(gdev, &desc->string, data_size);
                        break;
 
                case GREYBUS_TYPE_CPORT:
-                       retval = create_cport(gdev, desc, data_size);
+                       retval = create_cport(gdev, &desc->cport, data_size);
                        break;
 
                case GREYBUS_TYPE_INVALID: