43 lines
1.5 KiB
Diff
43 lines
1.5 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Stefan Reiter <s.reiter@proxmox.com>
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Date: Tue, 2 Mar 2021 16:11:54 +0100
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Subject: [PATCH] block/io: accept NULL qiov in bdrv_pad_request
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Some operations, e.g. block-stream, perform reads while discarding the
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results (only copy-on-read matters). In this case they will pass NULL as
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the target QEMUIOVector, which will however trip bdrv_pad_request, since
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it wants to extend its passed vector.
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Simply check for NULL and do nothing, there's no reason to pad the
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target if it will be discarded anyway.
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---
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block/io.c | 13 ++++++++-----
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1 file changed, 8 insertions(+), 5 deletions(-)
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diff --git a/block/io.c b/block/io.c
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index ec5e152bb7..08dee005ec 100644
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--- a/block/io.c
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+++ b/block/io.c
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@@ -1613,13 +1613,16 @@ static bool bdrv_pad_request(BlockDriverState *bs,
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return false;
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}
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- qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
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- *qiov, *qiov_offset, *bytes,
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- pad->buf + pad->buf_len - pad->tail, pad->tail);
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+ if (*qiov) {
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+ qemu_iovec_init_extended(&pad->local_qiov, pad->buf, pad->head,
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+ *qiov, *qiov_offset, *bytes,
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+ pad->buf + pad->buf_len - pad->tail, pad->tail);
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+ *qiov = &pad->local_qiov;
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+ *qiov_offset = 0;
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+ }
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+
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*bytes += pad->head + pad->tail;
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*offset -= pad->head;
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- *qiov = &pad->local_qiov;
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- *qiov_offset = 0;
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return true;
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}
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