+ [email protected]
On Thu, 21 May 2026 06:33:22 -0700 Kees Cook <[email protected]> wrote:
> Using the following Coccinelle script, convert struct kernel_param_ops
> .get callbacks from "char *" to "struct seq_buf *" when the only write
> to the buffer is via a final call of scnprintf(), snprintf(), sprintf(),
> or sysfs_emit().
>
> Since seq_buf_printf() will return -1 on overflow, and struct
> kernel_param_ops .get callbacks are expected to truncate without error,
> we must ignore the return value from seq_buf_print() and always return 0
> (as the length is calculated in the common dispatcher code).
>
> @@
> identifier FN, BUF, KP;
> expression FMT;
> expression list ARGS;
> @@
> int FN(
> - char *BUF
> + struct seq_buf *BUF
> , const struct kernel_param *KP)
> {
> ... when any
> (
> - return scnprintf(BUF, PAGE_SIZE, FMT, ARGS);
> |
> - return snprintf(BUF, PAGE_SIZE, FMT, ARGS);
> |
> - return sprintf(BUF, FMT, ARGS);
> |
> - return sysfs_emit(BUF, FMT, ARGS);
> )
> + seq_buf_printf(BUF, FMT, ARGS);
> + return 0;
> }
>
> No struct kernel_param_ops initializations need changing since
> DEFINE_KERNEL_PARAM_OPS already routes the pointer to .get or .get_str
> via _Generic based on the function signature, so converted callbacks
> are automatically moved from the .get_str to the .get callback.
>
> Signed-off-by: Kees Cook <[email protected]>
[...]
> mm/damon/lru_sort.c | 14 +++---
> mm/damon/reclaim.c | 14 +++---
> mm/damon/stat.c | 10 ++--
For the above DAMON changes,
Reviewed-by: SeongJae Park <[email protected]>
Thanks,
SJ
[...]
