qemu/scsi-bus-fix-incorrect-call-for-blk_error_retry_rese.patch

From 3ab10a5ad9bf1cbf3b4603f5a930a7924a07ad5a Mon Sep 17 00:00:00 2001
From: Yan Wang <wangyan122@huawei.com>
Date: Tue, 29 Mar 2022 12:05:56 +0800
Subject: [PATCH 1/2] scsi-bus: fix incorrect call for
 blk_error_retry_reset_timeout()

Fix commit 52115ca0("scsi-disk: Add support for retry on errors").
Call Stack:
    ...
    scsi_read_data()
        scsi_do_read(r, 0)
            scsi_disk_req_check_error()
                blk_error_retry_reset_timeout()
                    blk->retry_start_time = 0;

It will cause IO hang when storage network disconnected. Before the
storage network recovered, the upper call stack will reset the
retry_start_time, and cause the next IO operation not returned immediately.

Signed-off-by: Yan Wang <wangyan122@huawei.com>
---
 hw/scsi/scsi-disk.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 8661932a15..a66d2b0a98 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -255,10 +255,8 @@ static bool scsi_handle_rw_error(SCSIDiskReq *r, int ret, bool acct_failed)
     }
 }
 
-static bool scsi_disk_req_check_error(SCSIDiskReq *r, int ret, bool acct_failed)
+static bool scsi_disk_req_handle_error(SCSIDiskReq *r, int ret, bool acct_failed)
 {
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
-
     if (r->req.io_canceled) {
         scsi_req_cancel_complete(&r->req);
         return true;
@@ -268,6 +266,17 @@ static bool scsi_disk_req_check_error(SCSIDiskReq *r, int ret, bool acct_failed)
         return scsi_handle_rw_error(r, ret, acct_failed);
     }
 
+    return false;
+}
+
+static bool scsi_disk_req_check_error(SCSIDiskReq *r, int ret, bool acct_failed)
+{
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
+
+    if (r->req.io_canceled || ret < 0) {
+        return scsi_disk_req_handle_error(r, ret, acct_failed);
+    }
+
     blk_error_retry_reset_timeout(s->qdev.conf.blk);
     return false;
 }
@@ -418,7 +427,7 @@ static void scsi_do_read(SCSIDiskReq *r, int ret)
     SCSIDiskClass *sdc = (SCSIDiskClass *) object_get_class(OBJECT(s));
 
     assert (r->req.aiocb == NULL);
-    if (scsi_disk_req_check_error(r, ret, false)) {
+    if (scsi_disk_req_handle_error(r, ret, false)) {
         goto done;
     }
 
@@ -458,6 +467,9 @@ static void scsi_do_read_cb(void *opaque, int ret)
         block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
     } else {
         block_acct_done(blk_get_stats(s->qdev.conf.blk), &r->acct);
+        if (!r->req.io_canceled) {
+            blk_error_retry_reset_timeout(s->qdev.conf.blk);
+        }
     }
     scsi_do_read(opaque, ret);
     aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
-- 
2.27.0