From b9f63009f39c45c2a2d8c023ee5baaa4e2f55185 Mon Sep 17 00:00:00 2001
From: Ni Xun <nixun@baidu.com>
Date: Fri, 14 Sep 2018 20:19:17 +0800
Subject: [PATCH] nbd: add support for io_wait implement in nbd

according to commit:
     bdev: add spdk_bdev_queue_io_wait
This patch will make io_wait to support nbd

Change-Id: I9c8a6f5d20afbada45cedffe9d49846a992d2581
Signed-off-by: Ni Xun <nixun@baidu.com>
Signed-off-by: Li Lin <lilin24@baidu.com>
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/425594
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
---
 lib/nbd/nbd.c | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/lib/nbd/nbd.c b/lib/nbd/nbd.c
index 52c613d64..639f122ce 100644
--- a/lib/nbd/nbd.c
+++ b/lib/nbd/nbd.c
@@ -78,6 +78,9 @@ struct nbd_io {
 	 */
 	uint32_t		offset;
 
+	/* for bdev io_wait */
+	struct spdk_bdev_io_wait_entry bdev_io_wait;
+
 	TAILQ_ENTRY(nbd_io)	tailq;
 };
 
@@ -117,6 +120,9 @@ struct spdk_nbd_disk_globals {
 
 static struct spdk_nbd_disk_globals g_spdk_nbd;
 
+static int
+nbd_submit_bdev_io(struct spdk_nbd_disk *nbd, struct nbd_io *io);
+
 int
 spdk_nbd_init(void)
 {
@@ -451,6 +457,37 @@ nbd_io_done(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
 	}
 }
 
+static void
+nbd_resubmit_io(void *arg)
+{
+	struct nbd_io *io = (struct nbd_io *)arg;
+	struct spdk_nbd_disk *nbd = io->nbd;
+	int rc = 0;
+
+	rc = nbd_submit_bdev_io(nbd, io);
+	if (rc) {
+		SPDK_INFOLOG(SPDK_LOG_NBD, "nbd: io resubmit for dev %s , io_type %d, returned %d.\n",
+			     spdk_nbd_disk_get_bdev_name(nbd), from_be32(&io->req.type), rc);
+	}
+}
+
+static void
+nbd_queue_io(struct nbd_io *io)
+{
+	int rc;
+	struct spdk_bdev *bdev = io->nbd->bdev;
+
+	io->bdev_io_wait.bdev = bdev;
+	io->bdev_io_wait.cb_fn = nbd_resubmit_io;
+	io->bdev_io_wait.cb_arg = io;
+
+	rc = spdk_bdev_queue_io_wait(bdev, io->nbd->ch, &io->bdev_io_wait);
+	if (rc != 0) {
+		SPDK_ERRLOG("Queue io failed in nbd_queue_io, rc=%d.\n", rc);
+		nbd_io_done(NULL, false, io);
+	}
+}
+
 static int
 nbd_submit_bdev_io(struct spdk_nbd_disk *nbd, struct nbd_io *io)
 {
@@ -489,7 +526,13 @@ nbd_submit_bdev_io(struct spdk_nbd_disk *nbd, struct nbd_io *io)
 	}
 
 	if (rc < 0) {
-		nbd_io_done(NULL, false, io);
+		if (rc == -ENOMEM) {
+			SPDK_INFOLOG(SPDK_LOG_NBD, "No memory, start to queue io.\n");
+			nbd_queue_io(io);
+		} else {
+			SPDK_ERRLOG("nbd io failed in nbd_queue_io, rc=%d.\n", rc);
+			nbd_io_done(NULL, false, io);
+		}
 	}
 
 	return 0;