From 6952df035509717bdc46194b2a3d6ffb9349f267 Mon Sep 17 00:00:00 2001
From: Albert Lee <albertcc@tw.ibm.com>
Date: Mon, 6 Jun 2005 15:56:03 +0800
Subject: [PATCH] [PATCH] sg traverse fix for __atapi_pio_bytes()
Problem:
Incorrect md5sum when using ATAPI PIO mode to verify a distro CD.
Root cause: sg traverse problem.
In __atapi_pio_bytes(), if qc->cursg++ is increased and "goto
next_page" is executed, then sg is not updated to the new qc->cursg
and the old sg is overwritten with the new data.
Changes:
- Replace "goto next_page" with "goto next_sg" to make sg updated.
Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
---
drivers/scsi/libata-core.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 21d194c6ace3..9e58f134f68b 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2577,7 +2577,6 @@ static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
next_sg:
sg = &qc->sg[qc->cursg];
-next_page:
page = sg->page;
offset = sg->offset + qc->cursg_ofs;
@@ -2585,6 +2584,7 @@ static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
page = nth_page(page, (offset >> PAGE_SHIFT));
offset %= PAGE_SIZE;
+ /* don't overrun current sg */
count = min(sg->length - qc->cursg_ofs, bytes);
/* don't cross page boundaries */
@@ -2609,8 +2609,6 @@ static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
kunmap(page);
if (bytes) {
- if (qc->cursg_ofs < sg->length)
- goto next_page;
goto next_sg;
}
}
--
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