Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct dw_i3c_xfer.

[1] 
https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Alexandre Belloni <[email protected]>
Cc: Jeremy Kerr <[email protected]>
Cc: Joel Stanley <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
 drivers/i3c/master/dw-i3c-master.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c 
b/drivers/i3c/master/dw-i3c-master.c
index 9332ae5f6419..ef5751e91cc9 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -233,7 +233,7 @@ struct dw_i3c_xfer {
        struct completion comp;
        int ret;
        unsigned int ncmds;
-       struct dw_i3c_cmd cmds[];
+       struct dw_i3c_cmd cmds[] __counted_by(ncmds);
 };
 
 struct dw_i3c_i2c_dev_data {
-- 
2.34.1


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