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Fix bitstring allocation on 32-bit platforms

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sys/sys/bitstring.h
	Fix a rounding calculation that could undersize a bitstring on
	32-bit platforms.

tests/sys/sys/bitstring_test.h
	Add a test for bitstr_size

PR:		210260
Reported by:	Mark Millard
Reviewed by:	gibbs
Approved by:	re (marius)
Sponsored by:	Spectra Logic Corp
Differential Revision:	https://reviews.freebsd.org/D6848
This commit is contained in:
Alan Somers 2016-06-24 21:44:46 +00:00
parent 0367ff567c
commit 39ba705baf
2 changed files with 21 additions and 4 deletions
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13
sys/sys/bitstring.h
View File

@ -75,6 +75,12 @@ typedef unsigned long bitstr_t;
#define _BITSTR_MASK (~0UL)
#define _BITSTR_BITS (sizeof(bitstr_t) * 8)
#ifdef roundup2
#define _bit_roundup2 roundup2
#else
#define _bit_roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
#endif
/* bitstr_t in bit string containing the bit. */
static inline int
_bit_idx(int _bit)
@ -104,9 +110,8 @@ _bit_make_mask(int _start, int _stop)
}
/*----------------------------- Public Interface -----------------------------*/
/* Number of bytes consumed by a bit string of nbits bits */
#define bitstr_size(_nbits) \
(((_nbits) + _BITSTR_BITS - 1) / 8)
/* Number of bytes allocated for a bit string of nbits bits */
#define bitstr_size(_nbits) (_bit_roundup2(_nbits, _BITSTR_BITS) / 8)
/* Allocate a bit string initialized with no bits set. */
#ifdef _KERNEL
@ -123,7 +128,7 @@ bit_alloc(int _nbits)
}
#endif
/* Allocate a bit string on the stack with no bits set. */
/* Allocate a bit string on the stack */
#define bit_decl(name, nbits) \
((name)[bitstr_size(nbits) / sizeof(bitstr_t)])

12
tests/sys/sys/bitstring_test.c
View File

@ -102,6 +102,17 @@ ATF_TC_BODY(bitstr_in_struct, tc)
bit_nclear(test_struct.bitstr, 0, 8);
}
ATF_TC_WITHOUT_HEAD(bitstr_size);
ATF_TC_BODY(bitstr_size, tc)
{
size_t sob = sizeof(bitstr_t);
ATF_CHECK_EQ(0, bitstr_size(0));
ATF_CHECK_EQ(sob, bitstr_size(1));
ATF_CHECK_EQ(sob, bitstr_size(sob * 8));
ATF_CHECK_EQ(2 * sob, bitstr_size(sob * 8 + 1));
}
BITSTRING_TC_DEFINE(bit_set)
/* bitstr_t *bitstr, int nbits, const char *memloc */
{
@ -407,6 +418,7 @@ ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, bitstr_in_struct);
ATF_TP_ADD_TC(tp, bitstr_size);
BITSTRING_TC_ADD(tp, bit_set);
BITSTRING_TC_ADD(tp, bit_clear);
BITSTRING_TC_ADD(tp, bit_ffs);