Wrong cache invalidation in cfi_cmdset0001.c (2.6.21 kernel)

[Massimo CIRILLO]

We found an issue in cfi_cmdset0001.c file of 2.6.21 kernel.
It is related to cache region invalidation in the buffered
write procedure.

The original code performs cache invalidation from "adr" to "adr + len" in
do_write_buffer() while we modify region from "cmd_adr" to "len2" 
where len2 is equal to initial value of len.

The following is the patch to apply for 2.6.21 kernel.

--- a/drivers/mtd/chips/cfi_cmdset_0001.c	2007-11-26 18:06:37.000000000 +0100
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c	2007-11-26 18:06:44.000000000 +0100
@@ -1472,6 +1472,7 @@ static int __xipram do_write_buffer(stru
 	int ret, wbufsize, word_gap, words;
 	const struct kvec *vec;
 	unsigned long vec_seek;
+	int len2=len;
 
 	wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
 	adr += chip->start;
@@ -1578,7 +1579,7 @@ static int __xipram do_write_buffer(stru
 	chip->state = FL_WRITING;
 
 	ret = INVAL_CACHE_AND_WAIT(map, chip, cmd_adr,
-				   adr, len,
+				   cmd_adr, len2,
 				   chip->buffer_write_time);
 	if (ret) {
 		map_write(map, CMD(0x70), cmd_adr);

In any case we believe this patch should be valid also for the 2.6.22 and 2.6.23 kernel.

Looking forward feedbacks.