nbd: put get-bdev and register-poller to lib/nbd

nbd poller is put into spdk_nbd_disk.
nbd test app no longer needs to process spdk_bdev.
This enables upcomming patches to move nbd test app
functionality to SPDK library.

Change-Id: I1b563a49dc9488e8dcc20706be82b17fdbd07ff1
Signed-off-by: Xiaodong Liu <xiaodong.liu@intel.com>
Reviewed-on: https://review.gerrithub.io/390093
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>

include/spdk/nbd.h

@@ -37,14 +37,7 @@
 struct spdk_bdev;
 struct spdk_nbd_disk;
 
-struct spdk_nbd_disk *spdk_nbd_start(struct spdk_bdev *bdev, const char *nbd_path);
+struct spdk_nbd_disk *spdk_nbd_start(const char *bdev_name, const char *nbd_path);
-
-/**
- * Poll an NBD instance.
- *
- * \return 0 on success or negated errno values on error (e.g. connection closed).
- */
-int spdk_nbd_poll(struct spdk_nbd_disk *nbd);
 
 void spdk_nbd_stop(struct spdk_nbd_disk *nbd);
 

lib/nbd/nbd.c

@@ -75,6 +75,7 @@ struct spdk_nbd_disk {
 	int			kernel_sp_fd;
 	int			spdk_sp_fd;
 	struct nbd_io		io;
+	struct spdk_poller	*nbd_poller;
 	uint32_t		buf_align;
 };
 
@@ -123,6 +124,10 @@ _nbd_stop(struct spdk_nbd_disk *nbd)
 		close(nbd->kernel_sp_fd);
 	}
 
+	if (nbd->nbd_poller) {
+		spdk_poller_unregister(&nbd->nbd_poller);
+	}
+
 	free(nbd);
 }
 
@@ -286,8 +291,13 @@ process_request(struct spdk_nbd_disk *nbd)
 	return 0;
 }
 
-int
+/**
-spdk_nbd_poll(struct spdk_nbd_disk *nbd)
+ * Poll an NBD instance.
+ *
+ * \return 0 on success or negated errno values on error (e.g. connection closed).
+ */
+static int
+_spdk_nbd_poll(struct spdk_nbd_disk *nbd)
 {
 	struct nbd_io	*io = &nbd->io;
 	int		fd = nbd->spdk_sp_fd;
@@ -355,6 +365,19 @@ spdk_nbd_poll(struct spdk_nbd_disk *nbd)
 	return 0;
 }
 
+static void
+spdk_nbd_poll(void *arg)
+{
+	struct spdk_nbd_disk *nbd = arg;
+	int rc;
+
+	rc = _spdk_nbd_poll(nbd);
+	if (rc < 0) {
+		SPDK_NOTICELOG("spdk_nbd_poll got error %d; close it", rc);
+		spdk_nbd_stop(nbd);
+	}
+}
+
 static void *
 nbd_start_kernel(void *arg)
 {
@@ -388,15 +411,22 @@ nbd_start_kernel(void *arg)
 }
 
 struct spdk_nbd_disk *
-spdk_nbd_start(struct spdk_bdev *bdev, const char *nbd_path)
+spdk_nbd_start(const char *bdev_name, const char *nbd_path)
 {
 	struct spdk_nbd_disk	*nbd;
+	struct spdk_bdev	*bdev;
 	pthread_t		tid;
 	int			rc;
 	int			sp[2];
 	char			buf[64];
 	int			flag;
 
+	bdev = spdk_bdev_get_by_name(bdev_name);
+	if (bdev == NULL) {
+		SPDK_ERRLOG("no bdev %s exists\n", bdev_name);
+		return NULL;
+	}
+
 	nbd = calloc(1, sizeof(*nbd));
 	if (nbd == NULL) {
 		return NULL;
@@ -478,6 +508,8 @@ spdk_nbd_start(struct spdk_bdev *bdev, const char *nbd_path)
 	to_be32(&nbd->io.resp.magic, NBD_REPLY_MAGIC);
 	nbd->io.req_in_progress = true;
 
+	nbd->nbd_poller = spdk_poller_register(spdk_nbd_poll, nbd, 0);
+
 	return nbd;
 
 err:

test/lib/bdev/nbd/nbd.c

@@ -43,7 +43,6 @@
 #include "spdk/log.h"
 #include "spdk/util.h"
 
-static struct spdk_poller *g_nbd_poller;
 static struct spdk_nbd_disk *g_nbd_disk;
 static char *g_bdev_name;
 static char *g_nbd_name = "/dev/nbd0";
@@ -53,43 +52,18 @@ static char *g_nbd_name = "/dev/nbd0";
 static void
 nbd_shutdown(void)
 {
-	spdk_poller_unregister(&g_nbd_poller);
-
 	spdk_nbd_stop(g_nbd_disk);
 	spdk_app_stop(0);
 }
 
-static void
-nbd_poll(void *arg)
-{
-	int rc;
-
-	rc = spdk_nbd_poll(g_nbd_disk);
-	if (rc < 0) {
-		SPDK_NOTICELOG("spdk_nbd_poll() returned %d; shutting down", rc);
-		nbd_shutdown();
-	}
-}
-
 static void
 nbd_start(void *arg1, void *arg2)
 {
-	struct spdk_bdev	*bdev;
+	g_nbd_disk = spdk_nbd_start(g_bdev_name, g_nbd_name);
-
-	bdev = spdk_bdev_get_by_name(g_bdev_name);
-	if (bdev == NULL) {
-		SPDK_ERRLOG("no bdev %s exists\n", g_bdev_name);
-		spdk_app_stop(-1);
-		return;
-	}
-
-	g_nbd_disk = spdk_nbd_start(bdev, g_nbd_name);
 	if (g_nbd_disk == NULL) {
 		spdk_app_stop(-1);
 		return;
 	}
-
-	g_nbd_poller = spdk_poller_register(nbd_poll, NULL, 0);
 }
 
 static void usage(char *program_name)