From 30ca60c15a725f655e5d3f14e0238a066bc5aeb7 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Tue, 25 Mar 2008 15:06:55 -0700 Subject: cpumask: add cpumask_scnprintf_len function Add a new function cpumask_scnprintf_len() to return the number of characters needed to display "len" cpumask bits. The current method of allocating NR_CPUS bytes is incorrect as what's really needed is 9 characters per 32-bit word of cpumask bits (8 hex digits plus the seperator [','] or the terminating NULL.) This function provides the caller the means to allocate the correct string length. Cc: Paul Jackson Signed-off-by: Mike Travis Signed-off-by: Ingo Molnar --- lib/bitmap.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'lib/bitmap.c') diff --git a/lib/bitmap.c b/lib/bitmap.c index 2c9242e3fed..a6939e18d7b 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -315,6 +315,22 @@ int bitmap_scnprintf(char *buf, unsigned int buflen, } EXPORT_SYMBOL(bitmap_scnprintf); +/** + * bitmap_scnprintf_len - return buffer length needed to convert + * bitmap to an ASCII hex string. + * @len: number of bits to be converted + */ +int bitmap_scnprintf_len(unsigned int len) +{ + /* we need 9 chars per word for 32 bit words (8 hexdigits + sep/null) */ + int bitslen = ALIGN(len, CHUNKSZ); + int wordlen = CHUNKSZ / 4; + int buflen = (bitslen / wordlen) * (wordlen + 1) * sizeof(char); + + return buflen; +} +EXPORT_SYMBOL(bitmap_scnprintf_len); + /** * __bitmap_parse - convert an ASCII hex string into a bitmap. * @buf: pointer to buffer containing string. -- cgit v1.2.3