bump version to 5.2.0-11

[pve-qemu.git] / debian / patches / pve / 0046-block-io-accept-NULL-qiov-in-bdrv_pad_request.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Reiter <s.reiter@proxmox.com>
Date: Tue, 2 Mar 2021 16:11:54 +0100
Subject: [PATCH] block/io: accept NULL qiov in bdrv_pad_request

Some operations, e.g. block-stream, perform reads while discarding the
results (only copy-on-read matters). In this case they will pass NULL as
the target QEMUIOVector, which will however trip bdrv_pad_request, since
it wants to extend its passed vector.

Simply check for NULL and do nothing, there's no reason to pad the
target if it will be discarded anyway.
---
 block/io.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/block/io.c b/block/io.c
index ec5e152bb7..08dee005ec 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1613,13 +1613,16 @@ static bool bdrv_pad_request(BlockDriverState *bs,
         return false;
     }
 
-    qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
-                             *qiov, *qiov_offset, *bytes,
-                             pad->buf + pad->buf_len - pad->tail, pad->tail);
+    if (*qiov) {
+        qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
+                                *qiov, *qiov_offset, *bytes,
+                                pad->buf + pad->buf_len - pad->tail, pad->tail);
+        *qiov = &pad->local_qiov;
+        *qiov_offset = 0;
+    }
+
     *bytes += pad->head + pad->tail;
     *offset -= pad->head;
-    *qiov = &pad->local_qiov;
-    *qiov_offset = 0;
 
     return true;
 }