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Commit 30ca60c1 authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
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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 <pj@sgi.com>
Signed-off-by: default avatarMike Travis <travis@sgi.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9f0e738f

include/linux/bitmap.h

+1 −0
Original line number Diff line number Diff line
@@ -108,6 +108,7 @@ extern int __bitmap_weight(const unsigned long *bitmap, int bits); 


extern int bitmap_scnprintf(char *buf, unsigned int len,

			const unsigned long *src, int nbits);

extern int bitmap_scnprintf_len(unsigned int len);

extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,

			unsigned long *dst, int nbits);

extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,

include/linux/cpumask.h

+7 −0
Original line number Diff line number Diff line
@@ -273,6 +273,13 @@ static inline int __cpumask_scnprintf(char *buf, int len, 
	return bitmap_scnprintf(buf, len, srcp->bits, nbits);

}



#define cpumask_scnprintf_len(len) \

			__cpumask_scnprintf_len((len))

static inline int __cpumask_scnprintf_len(int len)

{

	return bitmap_scnprintf_len(len);

}



#define cpumask_parse_user(ubuf, ulen, dst) \

			__cpumask_parse_user((ubuf), (ulen), &(dst), NR_CPUS)

static inline int __cpumask_parse_user(const char __user *buf, int len,

lib/bitmap.c

+16 −0
Original line number Diff line number Diff line
@@ -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.