On Wed 13-11-24 16:51:03, Mateusz Guzik wrote: > It literally directly follows a spin_lock() call. > > This whacks an explicit barrier on x86-64. > > Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> > This plausibly can go away altogether, but I could not be arsed to > convince myself that's correct. Individuals willing to put in time are > welcome :) AFAICS there's nothing else really guaranteeing the last store to inode->i_state cannot be reordered up to after the wake up so I think the barrier should be there. Honza > > fs/inode.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/inode.c b/fs/inode.c > index e5a60084a7a9..b3db1234737f 100644 > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -817,7 +817,7 @@ static void evict(struct inode *inode) > * ___wait_var_event() either sees the bit cleared or > * waitqueue_active() check in wake_up_var() sees the waiter. > */ > - smp_mb(); > + smp_mb__after_spinlock(); > inode_wake_up_bit(inode, __I_NEW); > BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); > spin_unlock(&inode->i_lock); > -- > 2.43.0 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
