[Yaffs] Casting bug in yaffs_mtdif2.c

There is a minor bug in yaffs_mtdif2.c when converting from blockNo to
mtd offsets. If the offset ends up being > 2^31-1, then it gets
converted to a negative number, and then the loff_t gets stuff up.
However in general mtd supports up to 4GB (in theory, although I've
found a bunch of other things that make this difficult).

Anyway, I've attached a pretty trivial patch which adds a simple 2 line
conversion function, and calls this when necessary.

Andre

--
Bluewater Systems Ltd - ARM Technology Solutions Centre

       Andre Renaud                             Bluewater Systems Ltd
Phone: +64 3 3779127 (Aus 1 800 148 751)        Level 17, 119 Armagh St
Fax:   +64 3 3779135                            PO Box 13889
Email: arenaud@bluewatersys.com                 Christchurch
Web:   http://www.bluewatersys.com              New Zealand

Index: yaffs_mtdif2.c

===================================================================
--- yaffs_mtdif2.c    (revision 1376)
+++ yaffs_mtdif2.c    (working copy)
@@ -27,6 +27,12 @@

#include "yaffs_packedtags2.h"

+static loff_t block2offset (yaffs_Device *dev, int blockNo)
+{
+        return (loff_t)blockNo * (loff_t)dev->nChunksPerBlock * 
+                (loff_t)dev->nDataBytesPerChunk;
+}
+
 int nandmtd2_WriteChunkWithTagsToNAND(yaffs_Device * dev, int chunkInNAND,
                       const __u8 * data,
                       const yaffs_ExtendedTags * tags)
@@ -176,9 +182,7 @@
       (TSTR("nandmtd2_MarkNANDBlockBad %d" TENDSTR), blockNo));

     retval =
-        mtd->block_markbad(mtd,
-                   blockNo * dev->nChunksPerBlock *
-                   dev->nDataBytesPerChunk);
+        mtd->block_markbad(mtd, block2offset (dev, blockNo));

     if (retval == 0)
         return YAFFS_OK;
@@ -196,9 +200,7 @@
     T(YAFFS_TRACE_MTD,
       (TSTR("nandmtd2_QueryNANDBlock %d" TENDSTR), blockNo));
     retval =
-        mtd->block_isbad(mtd,
-                 blockNo * dev->nChunksPerBlock *
-                 dev->nDataBytesPerChunk);
+        mtd->block_isbad(mtd, block2offset (dev, blockNo));

     if (retval) {
         T(YAFFS_TRACE_MTD, (TSTR("block is bad" TENDSTR)));