ocf: add shared cache instance context

Introduce cache context structure that is going to be used
  for sharing per cache info. For example: management queue,
  cleaner_channel, cleaner_thread.

Lifetime of this structure ends with last vbdev that gets unregistered
  and NOT when cache stops because cache does not have to be freed
  there.

Change-Id: I66252084d7efda92edd10fb737c8e9c8169b4f6d
Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/451403
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

lib/bdev/ocf/ctx.c

@@ -288,6 +288,18 @@ vbdev_ocf_ctx_data_secure_erase(ctx_data_t *ctx_data)
 	}
 }
 
+void vbdev_ocf_cache_ctx_put(struct vbdev_ocf_cache_ctx *ctx)
+{
+	if (env_atomic_dec_return(&ctx->refcnt) == 0) {
+		free(ctx);
+	}
+}
+
+void vbdev_ocf_cache_ctx_get(struct vbdev_ocf_cache_ctx *ctx)
+{
+	env_atomic_inc(&ctx->refcnt);
+}
+
 static int
 vbdev_ocf_ctx_cleaner_init(ocf_cleaner_t c)
 {

lib/bdev/ocf/ctx.h

@@ -42,6 +42,14 @@ extern ocf_ctx_t vbdev_ocf_ctx;
 
 #define SPDK_OBJECT 1
 
+/* Context of cache instance */
+struct vbdev_ocf_cache_ctx {
+	env_atomic                   refcnt;
+};
+
+void vbdev_ocf_cache_ctx_put(struct vbdev_ocf_cache_ctx *ctx);
+void vbdev_ocf_cache_ctx_get(struct vbdev_ocf_cache_ctx *ctx);
+
 int vbdev_ocf_ctx_init(void);
 void vbdev_ocf_ctx_cleanup(void);
 

lib/bdev/ocf/vbdev_ocf.c

@@ -171,6 +171,7 @@ static void
 unregister_finish(struct vbdev_ocf *vbdev)
 {
 	spdk_bdev_destruct_done(&vbdev->exp_bdev, vbdev->state.stop_status);
+	vbdev_ocf_cache_ctx_put(vbdev->cache_ctx);
 	vbdev_ocf_mngt_continue(vbdev, 0);
 }
 
@@ -839,18 +840,31 @@ start_cache(struct vbdev_ocf *vbdev)
 			       vbdev->name, vbdev->cache.name);
 		vbdev->ocf_cache = existing;
 		vbdev->cache.id = ocf_cache_get_id(existing);
+		vbdev->cache_ctx = ocf_cache_get_priv(existing);
+		vbdev_ocf_cache_ctx_get(vbdev->cache_ctx);
 		vbdev_ocf_mngt_continue(vbdev, 0);
 		return;
 	}
 
+	vbdev->cache_ctx = calloc(1, sizeof(struct vbdev_ocf_cache_ctx));
+	if (vbdev->cache_ctx == NULL) {
+		vbdev->mngt_ctx.status = -ENOMEM;
+		vbdev_ocf_mngt_stop(vbdev);
+		return;
+	}
+
+	vbdev_ocf_cache_ctx_get(vbdev->cache_ctx);
+
 	rc = ocf_mngt_cache_start(vbdev_ocf_ctx, &vbdev->ocf_cache, &vbdev->cfg.cache);
 	if (rc) {
+		vbdev_ocf_cache_ctx_put(vbdev->cache_ctx);
 		vbdev->mngt_ctx.status = rc;
 		vbdev_ocf_mngt_stop(vbdev);
 		return;
 	}
 
 	vbdev->cache.id = ocf_cache_get_id(vbdev->ocf_cache);
+	ocf_cache_set_priv(vbdev->ocf_cache, vbdev->cache_ctx);
 
 	ocf_mngt_cache_attach(vbdev->ocf_cache, &vbdev->cfg.device, start_cache_cmpl, vbdev);
 }

lib/bdev/ocf/vbdev_ocf.h

@@ -156,6 +156,8 @@ struct vbdev_ocf {
 
 	/* Management context */
 	struct vbdev_ocf_mngt_ctx    mngt_ctx;
+	/* Cache conext */
+	struct vbdev_ocf_cache_ctx  *cache_ctx;
 
 	/* Exposed SPDK bdev. Registered in bdev layer */
 	struct spdk_bdev             exp_bdev;