[PATCH libata-2.6 2/5] Fix sg increase problem in __atapi_pio_bytes()

[PATCH libata-2.6 2/5] Fix sg increase problem in __atapi_pio_bytes()

[Albert Lee]

[-- Attachment #1: Type: text/plain, Size: 1088 bytes --]

Hi Jeff,

Problem:
   In __atapi_pio_bytes(), after qc->cursg++ increased, if "goto next_page" is executed,
then sg is not updated and the old sg is overwritten with the new data.

Changes:
- Replace goto next_page by goto next_sg.

   Attached please find the patch against the libata-2.6 tree for your review. Thanks.

Albert

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
---------------------------------------
--- libata-2.6-sgdma/drivers/scsi/libata-core.c	2005-03-17 17:23:42.000000000 +0800
+++ libata-2.6-atapi_pio_bytes/drivers/scsi/libata-core.c	2005-03-18 13:20:01.000000000 +0800
@@ -2340,7 +2340,6 @@
  next_sg:
  	sg = &qc->sg[qc->cursg];

-next_page:
  	page = sg->page;
  	offset = sg->offset + qc->cursg_ofs;

@@ -2348,6 +2347,7 @@
  	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 */
@@ -2372,8 +2372,6 @@
  	kunmap(page);

  	if (bytes) {
-		if (qc->cursg_ofs < sg->length)
-			goto next_page;
  		goto next_sg;
  	}
  }


[-- Attachment #2: cursg_fix.diff --]
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--- libata-2.6-sgdma/drivers/scsi/libata-core.c	2005-03-17 17:23:42.000000000 +0800
+++ libata-2.6-atapi_pio_bytes/drivers/scsi/libata-core.c	2005-03-18 13:20:01.000000000 +0800
@@ -2340,7 +2340,6 @@
 next_sg:
 	sg = &qc->sg[qc->cursg];
 
-next_page:
 	page = sg->page;
 	offset = sg->offset + qc->cursg_ofs;
 
@@ -2348,6 +2347,7 @@
 	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 */
@@ -2372,8 +2372,6 @@
 	kunmap(page);
 
 	if (bytes) {
-		if (qc->cursg_ofs < sg->length)
-			goto next_page;
 		goto next_sg;
 	}
 }