diff options
Diffstat (limited to 'lib/bitmap.c')
| -rw-r--r-- | lib/bitmap.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 73746d96af81..663dd81967d4 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -568,6 +568,24 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, * and it can break the size limit of converted decimal list and hexadecimal * bitmask. * + * WARNING! + * + * This function is not a replacement for sprintf() or bitmap_print_to_pagebuf(). + * It is intended to workaround sysfs limitations discussed above and should be + * used carefully in general case for the following reasons: + * - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf(). + * - Memory complexity is O(nbits), comparing to O(1) for snprintf(). + * - @off and @count are NOT offset and number of bits to print. + * - If printing part of bitmap as list, the resulting string is not a correct + * list representation of bitmap. Particularly, some bits within or out of + * related interval may be erroneously set or unset. The format of the string + * may be broken, so bitmap_parselist-like parser may fail parsing it. + * - If printing the whole bitmap as list by parts, user must ensure the order + * of calls of the function such that the offset is incremented linearly. + * - If printing the whole bitmap as list by parts, user must keep bitmap + * unchanged between the very first and very last call. Otherwise concatenated + * result may be incorrect, and format may be broken. + * * Returns the number of characters actually printed to @buf */ int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp, |