drbd: perpare for genetlink parallel_ops

Because all administrative requests via genetlink have been globally
serialized via genl_lock(), we used to have one static struct
drbd_config_context "admin context".

Move this on-stack to the respective callback functions.

This will allow us to selectively drop the genl_lock()
(or use genl_family->parallel_ops) in the future.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/block/drbd/drbd_int.h

@@ -814,6 +814,28 @@ struct drbd_device {
 	struct submit_worker submit;
 };
 
+struct drbd_config_context {
+	/* assigned from drbd_genlmsghdr */
+	unsigned int minor;
+	/* assigned from request attributes, if present */
+	unsigned int volume;
+#define VOLUME_UNSPECIFIED		(-1U)
+	/* pointer into the request skb,
+	 * limited lifetime! */
+	char *resource_name;
+	struct nlattr *my_addr;
+	struct nlattr *peer_addr;
+
+	/* reply buffer */
+	struct sk_buff *reply_skb;
+	/* pointer into reply buffer */
+	struct drbd_genlmsghdr *reply_dh;
+	/* resolved from attributes, if possible */
+	struct drbd_device *device;
+	struct drbd_resource *resource;
+	struct drbd_connection *connection;
+};
+
 static inline struct drbd_device *minor_to_device(unsigned int minor)
 {
 	return (struct drbd_device *)idr_find(&drbd_devices, minor);
@@ -1229,9 +1251,9 @@ extern struct bio *bio_alloc_drbd(gfp_t gfp_mask);
 extern rwlock_t global_state_lock;
 
 extern int conn_lowest_minor(struct drbd_connection *connection);
-enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned int minor, int vnr);
+extern enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor);
 extern void drbd_destroy_device(struct kref *kref);
-extern void drbd_delete_device(struct drbd_device *mdev);
+extern void drbd_delete_device(struct drbd_device *device);
 
 extern struct drbd_resource *drbd_create_resource(const char *name);
 extern void drbd_free_resource(struct drbd_resource *resource);
@@ -1257,7 +1279,7 @@ extern int is_valid_ar_handle(struct drbd_request *, sector_t);
 
 
 /* drbd_nl.c */
-extern int drbd_msg_put_info(const char *info);
+extern int drbd_msg_put_info(struct sk_buff *skb, const char *info);
 extern void drbd_suspend_io(struct drbd_device *device);
 extern void drbd_resume_io(struct drbd_device *device);
 extern char *ppsize(char *buf, unsigned long long size);

drivers/block/drbd/drbd_main.c

@@ -2687,14 +2687,16 @@ static int init_submitter(struct drbd_device *device)
 	return 0;
 }
 
-enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned int minor, int vnr)
+enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor)
 {
+	struct drbd_resource *resource = adm_ctx->resource;
 	struct drbd_connection *connection;
 	struct drbd_device *device;
 	struct drbd_peer_device *peer_device, *tmp_peer_device;
 	struct gendisk *disk;
 	struct request_queue *q;
 	int id;
+	int vnr = adm_ctx->volume;
 	enum drbd_ret_code err = ERR_NOMEM;
 
 	device = minor_to_device(minor);
@@ -2763,7 +2765,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 	if (id < 0) {
 		if (id == -ENOSPC) {
 			err = ERR_MINOR_EXISTS;
-			drbd_msg_put_info("requested minor exists already");
+			drbd_msg_put_info(adm_ctx->reply_skb, "requested minor exists already");
 		}
 		goto out_no_minor_idr;
 	}
@@ -2773,7 +2775,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 	if (id < 0) {
 		if (id == -ENOSPC) {
 			err = ERR_MINOR_EXISTS;
-			drbd_msg_put_info("requested minor exists already");
+			drbd_msg_put_info(adm_ctx->reply_skb, "requested minor exists already");
 		}
 		goto out_idr_remove_minor;
 	}
@@ -2794,7 +2796,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 		if (id < 0) {
 			if (id == -ENOSPC) {
 				err = ERR_INVALID_REQUEST;
-				drbd_msg_put_info("requested volume exists already");
+				drbd_msg_put_info(adm_ctx->reply_skb, "requested volume exists already");
 			}
 			goto out_idr_remove_from_resource;
 		}
@@ -2803,7 +2805,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 
 	if (init_submitter(device)) {
 		err = ERR_NOMEM;
-		drbd_msg_put_info("unable to create submit workqueue");
+		drbd_msg_put_info(adm_ctx->reply_skb, "unable to create submit workqueue");
 		goto out_idr_remove_vol;
 	}