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SubjectRecent patch to cfi.h screws MTD CFI layer
Date
The recent patch in 2.4.0-test11 causes MTD to oops the kernel:

diff -u --recursive --new-file v2.4.0-test10/linux/include/linux/mtd/cfi.h linux/include/linux/mtd/cfi.
h
--- v2.4.0-test10/linux/include/linux/mtd/cfi.h Tue Jul 4 10:12:34 2000
+++ linux/include/linux/mtd/cfi.h Tue Nov 7 10:46:04 2000
@@ -92,6 +92,7 @@
int numchips;
unsigned long chipshift; /* Because they're of the same type */
struct flchip chips[0]; /* per-chip data structure for each chip */
+ const char *im_name; /* inter_module name for cmdset_setup */
};

#define MAX_CFI_CHIPS 8 /* Entirely arbitrary to avoid realloc() */
This is what happens to chips[].start during initialisation:

chip 0 start 0
chip 1 start 800000
chip 2 start 1000000
chip 3 start 1800000
Intel/Sharp Extended Query Table at 0x0031
chip 0 start c013b45c <--- overwritten by write to im_name
chip 1 start 800000
chip 2 start 1000000
chip 3 start 1800000
chip 0 start c013b45c
chip 1 start 800000
chip 2 start 1000000
chip 3 start 1800000
number of CFI chips: 4
chip 0 start c013b45c
chip 1 start 800000
chip 2 start 1000000
chip 3 start 1800000
Here is a patch that fixes the problem, and includes a warning to tell
people not to add extra fields after the "chips" element.

--- linux.orig/include/linux/mtd/cfi.h Sat Nov 18 21:54:02 2000
+++ linux/include/linux/mtd/cfi.h Fri Nov 24 17:57:06 2000
@@ -209,8 +209,9 @@
must be of the same type. */
int numchips;
unsigned long chipshift; /* Because they're of the same type */
- struct flchip chips[0]; /* per-chip data structure for each chip */
const char *im_name; /* inter_module name for cmdset_setup */
+ struct flchip chips[0]; /* per-chip data structure for each chip */
+ /* do not add extra fields after "chips" */
};

#define MAX_CFI_CHIPS 8 /* Entirely arbitrary to avoid realloc() */
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