Messages in this thread | | | Subject | Re: Kernel crash after using new Intel NIC (igb) | From | Eric Dumazet <> | Date | Sat, 28 May 2011 07:41:25 +0200 |
| |
Le vendredi 27 mai 2011 à 14:14 -0700, Arun Sharma a écrit :
> The attached works for me for x86_64. Cc'ing Ingo/Thomas for comment. > > -Arun > > atomic: Refactor atomic_add_unless > > Commit 686a7e3 (inetpeer: fix race in unused_list manipulations) > in net-2.6 added a atomic_add_unless_return() variant that tries > to detect 0->1 transitions of an atomic reference count. > > This sounds like a generic functionality that could be expressed > in terms of an __atomic_add_unless() that returned the old value > instead of a bool. > > Signed-off-by: Arun Sharma <asharma@fb.com> > --- > arch/x86/include/asm/atomic.h | 22 ++++++++++++++++++---- > 1 files changed, 18 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h > index 952a826..bbdbffe 100644 > --- a/arch/x86/include/asm/atomic.h > +++ b/arch/x86/include/asm/atomic.h > @@ -221,15 +221,15 @@ static inline int atomic_xchg(atomic_t *v, int new) > } > > /** > - * atomic_add_unless - add unless the number is already a given value > + * __atomic_add_unless - add unless the number is already a given value > * @v: pointer of type atomic_t > * @a: the amount to add to v... > * @u: ...unless v is equal to u. > * > * Atomically adds @a to @v, so long as @v was not already @u. > - * Returns non-zero if @v was not @u, and zero otherwise. > + * Returns the old value of v > */ > -static inline int atomic_add_unless(atomic_t *v, int a, int u) > +static inline int __atomic_add_unless(atomic_t *v, int a, int u) > { > int c, old; > c = atomic_read(v); > @@ -241,7 +241,21 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u) > break; > c = old; > } > - return c != (u); > + return c; > +} > + > +/** > + * atomic_add_unless - add unless the number is already a given value > + * @v: pointer of type atomic_t > + * @a: the amount to add to v... > + * @u: ...unless v is equal to u. > + * > + * Atomically adds @a to @v, so long as @v was not already @u. > + * Returns non-zero if @v was not @u, and zero otherwise. > + */ > +static inline int atomic_add_unless(atomic_t *v, int a, int u) > +{ > + return __atomic_add_unless(v, a, u) != u; > } > > #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
As I said, atomic_add_unless() has several implementations in various arches. You must take care of all, not only x86.
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |