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bitmap: assert that start and nr are non negative 

commit e1123a3b introduced a data corruption regression
in the iscsi driver because it passed -1 as nr to bitmap_set
and bitmap_clear. Add an assertion to catch such flaws earlier.

Suggested-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Message-Id: <1484844230-24490-1-git-send-email-pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Lieven 2017-01-19 17:43:50 +01:00 committed by Paolo Bonzini
parent a049223ab1
commit e12ed72e5c
1 changed files with 8 additions and 0 deletions
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8
util/bitmap.c
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@ -164,6 +164,8 @@ void bitmap_set(unsigned long *map, long start, long nr)
int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
assert(start >= 0 && nr >= 0);
while (nr - bits_to_set >= 0) {
*p |= mask_to_set;
nr -= bits_to_set;
@ -184,6 +186,8 @@ void bitmap_set_atomic(unsigned long *map, long start, long nr)
int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
assert(start >= 0 && nr >= 0);
/* First word */
if (nr - bits_to_set > 0) {
atomic_or(p, mask_to_set);
@ -221,6 +225,8 @@ void bitmap_clear(unsigned long *map, long start, long nr)
int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
assert(start >= 0 && nr >= 0);
while (nr - bits_to_clear >= 0) {
*p &= ~mask_to_clear;
nr -= bits_to_clear;
@ -243,6 +249,8 @@ bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr)
unsigned long dirty = 0;
unsigned long old_bits;
assert(start >= 0 && nr >= 0);
/* First word */
if (nr - bits_to_clear > 0) {
old_bits = atomic_fetch_and(p, ~mask_to_clear);