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From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: John Snow <jsnow@redhat.com>, Kevin Wolf <kwolf@redhat.com>,
	<qemu-block@nongnu.org>, Hanna Reitz <hreitz@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Xiang Zheng <zhengxiang9@huawei.com>
Subject: [PATCH] pflash: fix sectors vs bytes confusion in blk_pread_nonzeroes()
Date: Mon, 29 Jan 2024 19:27:12 -0500	[thread overview]
Message-ID: <20240130002712.257815-1-stefanha@redhat.com> (raw)

The following expression is incorrect because blk_pread_nonzeroes()
deals in units of bytes, not sectors:

  bytes = MIN(size - offset, BDRV_REQUEST_MAX_SECTORS)
                                              ^^^^^^^

BDRV_REQUEST_MAX_BYTES is the appropriate constant.

Fixes: a4b15a8b9ef2 ("pflash: Only read non-zero parts of backend image")
Cc: Xiang Zheng <zhengxiang9@huawei.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/block/block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/block/block.c b/hw/block/block.c
index 9f52ee6e72..ff503002aa 100644
--- a/hw/block/block.c
+++ b/hw/block/block.c
@@ -30,7 +30,7 @@ static int blk_pread_nonzeroes(BlockBackend *blk, hwaddr size, void *buf)
     BlockDriverState *bs = blk_bs(blk);
 
     for (;;) {
-        bytes = MIN(size - offset, BDRV_REQUEST_MAX_SECTORS);
+        bytes = MIN(size - offset, BDRV_REQUEST_MAX_BYTES);
         if (bytes <= 0) {
             return 0;
         }
-- 
2.43.0



             reply	other threads:[~2024-01-30  0:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-30  0:27 Stefan Hajnoczi [this message]
2024-01-30  8:31 ` [PATCH] pflash: fix sectors vs bytes confusion in blk_pread_nonzeroes() Philippe Mathieu-Daudé
2024-01-30 21:18 ` Stefan Hajnoczi
2024-02-01 11:37 ` Michael Tokarev
2024-02-08 21:21   ` Stefan Hajnoczi
2024-02-09  7:44     ` Michael Tokarev

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