| Message ID | 20240902110654.2685917-1-ruanjinjie@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | a7293f0998a24344755fa69af5717055f20e5eaf |
| Headers | show |
| Series | [-next] rcu: Use the BITS_PER_LONG macro | expand |
On 2024-09-02 07:06, Jinjie Ruan wrote: > sizeof(unsigned long) * 8 is the number of bits in an unsigned long > variable, replace it with BITS_PER_LONG macro to make it simpler. An alternative would be: if (rcu_fanout_leaf < 2 || sizeof_field(struct rcu_node, qsmask) * CHAR_BIT) { which would then tie the check to validated member type. But it's slightly more verbose, so it's up to the maintainer really. Thanks, Mathieu > > Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> > --- > kernel/rcu/tree.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index a60616e69b66..b48864df415c 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -5579,8 +5579,7 @@ void rcu_init_geometry(void) > * Complain and fall back to the compile-time values if this > * limit is exceeded. > */ > - if (rcu_fanout_leaf < 2 || > - rcu_fanout_leaf > sizeof(unsigned long) * 8) { > + if (rcu_fanout_leaf < 2 || rcu_fanout_leaf > BITS_PER_LONG) { > rcu_fanout_leaf = RCU_FANOUT_LEAF; > WARN_ON(1); > return;
On 2024/9/2 20:16, Mathieu Desnoyers wrote: > On 2024-09-02 07:06, Jinjie Ruan wrote: >> sizeof(unsigned long) * 8 is the number of bits in an unsigned long >> variable, replace it with BITS_PER_LONG macro to make it simpler. > > An alternative would be: > > if (rcu_fanout_leaf < 2 || sizeof_field(struct rcu_node, qsmask) * > CHAR_BIT) { > > which would then tie the check to validated member type. But it's > slightly more verbose, so it's up to the maintainer really. Yes, it reflects the original purpose but it is too long. > > Thanks, > > Mathieu > >> >> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> >> --- >> kernel/rcu/tree.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c >> index a60616e69b66..b48864df415c 100644 >> --- a/kernel/rcu/tree.c >> +++ b/kernel/rcu/tree.c >> @@ -5579,8 +5579,7 @@ void rcu_init_geometry(void) >> * Complain and fall back to the compile-time values if this >> * limit is exceeded. >> */ >> - if (rcu_fanout_leaf < 2 || >> - rcu_fanout_leaf > sizeof(unsigned long) * 8) { >> + if (rcu_fanout_leaf < 2 || rcu_fanout_leaf > BITS_PER_LONG) { >> rcu_fanout_leaf = RCU_FANOUT_LEAF; >> WARN_ON(1); >> return; >
On Mon, Sep 02, 2024 at 07:06:54PM +0800, Jinjie Ruan wrote: > sizeof(unsigned long) * 8 is the number of bits in an unsigned long > variable, replace it with BITS_PER_LONG macro to make it simpler. > > Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Either Jinjie's or Mathieu's formulation works for me. But Jinjie was here first, so: Reviewed-by: Paul E. McKenney <paulmck@kernel.org> > --- > kernel/rcu/tree.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index a60616e69b66..b48864df415c 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -5579,8 +5579,7 @@ void rcu_init_geometry(void) > * Complain and fall back to the compile-time values if this > * limit is exceeded. > */ > - if (rcu_fanout_leaf < 2 || > - rcu_fanout_leaf > sizeof(unsigned long) * 8) { > + if (rcu_fanout_leaf < 2 || rcu_fanout_leaf > BITS_PER_LONG) { > rcu_fanout_leaf = RCU_FANOUT_LEAF; > WARN_ON(1); > return; > -- > 2.34.1 >
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a60616e69b66..b48864df415c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -5579,8 +5579,7 @@ void rcu_init_geometry(void) * Complain and fall back to the compile-time values if this * limit is exceeded. */ - if (rcu_fanout_leaf < 2 || - rcu_fanout_leaf > sizeof(unsigned long) * 8) { + if (rcu_fanout_leaf < 2 || rcu_fanout_leaf > BITS_PER_LONG) { rcu_fanout_leaf = RCU_FANOUT_LEAF; WARN_ON(1); return;
sizeof(unsigned long) * 8 is the number of bits in an unsigned long variable, replace it with BITS_PER_LONG macro to make it simpler. Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- kernel/rcu/tree.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)