[PATCH v4 1/7] nbd: simplify find_fallback() by removing redundant logic

[Yang Erkun <yangerkun@huawei.com>]

From: Long Li <leo.lilong@huawei.com>

Remove the intermediate new_index variable and return -1 directly.
The second conditional checking nsock->fallback_index validity is the
logical inverse of the first, so drop it and let execution fall through
naturally. Consolidate the two identical dev_err_ratelimited() + return
paths into a single no_fallback label to reduce duplication.

Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: Yu Kuai <yukuai@fygo.io>
---
 drivers/block/nbd.c | 37 ++++++++++++++-----------------------
 1 file changed, 14 insertions(+), 23 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 8f10762e90ef..b1a5acd57426 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1061,40 +1061,31 @@ static int find_fallback(struct nbd_device *nbd, int index)
 	int new_index = -1;
 	struct nbd_sock *nsock = config->socks[index];
 	int fallback = nsock->fallback_index;
+	int i;
 
 	if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
 		return new_index;
 
-	if (config->num_connections <= 1) {
-		dev_err_ratelimited(disk_to_dev(nbd->disk),
-				    "Dead connection, failed to find a fallback\n");
-		return new_index;
-	}
+	if (config->num_connections <= 1)
+		goto no_fallback;
 
 	if (fallback >= 0 && fallback < config->num_connections &&
 	    !config->socks[fallback]->dead)
 		return fallback;
 
-	if (nsock->fallback_index < 0 ||
-	    nsock->fallback_index >= config->num_connections ||
-	    config->socks[nsock->fallback_index]->dead) {
-		int i;
-		for (i = 0; i < config->num_connections; i++) {
-			if (i == index)
-				continue;
-			if (!config->socks[i]->dead) {
-				new_index = i;
-				break;
-			}
-		}
-		nsock->fallback_index = new_index;
-		if (new_index < 0) {
-			dev_err_ratelimited(disk_to_dev(nbd->disk),
-					    "Dead connection, failed to find a fallback\n");
-			return new_index;
+	for (i = 0; i < config->num_connections; i++) {
+		if (i != index && !config->socks[i]->dead) {
+			new_index = i;
+			break;
 		}
 	}
-	new_index = nsock->fallback_index;
+	nsock->fallback_index = new_index;
+	if (new_index >= 0)
+		return new_index;
+
+no_fallback:
+	dev_err_ratelimited(disk_to_dev(nbd->disk),
+			    "Dead connection, failed to find a fallback\n");
 	return new_index;
 }
 
-- 
2.52.0