From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Subject: lib/bitmap.c: simplify bitmap_print_to_pagebuf() len is guaranteed to lie in [1, PAGE_SIZE]. If scnprintf is called with a buffer size of 1, it is guaranteed to return 0. So in the extremely unlikely case of having just one byte remaining in the page, let's just call scnprintf anyway. The only difference is that this will write a '\0' to that final byte in the page, but that's an improvement: We now guarantee that after the call, buf is a properly terminated C string of length exactly the return value. Link: http://lkml.kernel.org/r/20180818131623.8755-8-linux@xxxxxxxxxxxxxxxxxx Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> Cc: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx> Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Cc: Sudeep Holla <sudeep.holla@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/bitmap.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) --- a/lib/bitmap.c~lib-bitmapc-simplify-bitmap_print_to_pagebuf +++ a/lib/bitmap.c @@ -471,12 +471,9 @@ int bitmap_print_to_pagebuf(bool list, c int nmaskbits) { ptrdiff_t len = PAGE_SIZE - offset_in_page(buf); - int n = 0; - if (len > 1) - n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : - scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); - return n; + return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : + scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); } EXPORT_SYMBOL(bitmap_print_to_pagebuf); _
