[MIPS] Fix bug in atomic_sub_if_positive.

The branch optimization fixes in 2.6.21 introduced a bug in
atomic_sub_if_positive that causes it to return even when the sc
instruction fails. The result is that e.g. down_trylock becomes unreliable
as the semaphore counter is not always decremented.

Original MUA-shredded patch from Morten Larsen <mlarsen@broadcom.com>.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle 2008-07-03 23:28:35 +01:00
parent bf9127c363
commit 5095202603

View File

@ -283,10 +283,10 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
" beqz %0, 2f \n"
" subu %0, %1, %3 \n"
" .set reorder \n"
"1: \n"
" .subsection 2 \n"
"2: b 1b \n"
" .previous \n"
"1: \n"
" .set mips0 \n"
: "=&r" (result), "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter)
@ -664,10 +664,10 @@ static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
" beqz %0, 2f \n"
" dsubu %0, %1, %3 \n"
" .set reorder \n"
"1: \n"
" .subsection 2 \n"
"2: b 1b \n"
" .previous \n"
"1: \n"
" .set mips0 \n"
: "=&r" (result), "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter)