On Mon, Feb 17, 2014 at 01:35:56PM -0800, Paul E. McKenney wrote: > From: "Paul E. McKenney" <[email protected]> > > (Trivial patch.) > > If the code is looking at the RCU-protected pointer itself, but not > dereferencing it, the rcu_dereference() functions can be downgraded to > rcu_access_pointer(). This commit makes this downgrade in __alloc_fd(), > which simply compares the RCU-protected pointer against NULL with no > dereferencing. > > Signed-off-by: Paul E. McKenney <[email protected]> > Cc: Alexander Viro <[email protected]> > Cc: [email protected]
I'm beginning to wonder if this common pattern ought to have an rcu_pointer_is_null(), which would not return the pointer, only the boolean. Regardless, for this patch: Reviewed-by: Josh Triplett <[email protected]> > fs/file.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/file.c b/fs/file.c > index db25c2bdfe46..18f7d27855c4 100644 > --- a/fs/file.c > +++ b/fs/file.c > @@ -497,7 +497,7 @@ repeat: > error = fd; > #if 1 > /* Sanity check */ > - if (rcu_dereference_raw(fdt->fd[fd]) != NULL) { > + if (rcu_access_pointer(fdt->fd[fd]) != NULL) { > printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd); > rcu_assign_pointer(fdt->fd[fd], NULL); > } > -- > 1.8.1.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
