Re: [PATCH] rwlock_is_locked undefined for UP systems

[Nikita Danilov <Nikita@Namesys.COM>]

Joe Thornber writes:
 > On Fri, Jan 16, 2004 at 02:55:50PM +0100, Arjan van de Ven wrote:
 > > On Fri, 2004-01-16 at 14:45, Prashanth T wrote:
 > > > Hi,
 > > >     I had to use rwlock_is_locked( ) with linux2.6 for kdb and noticed that
 > > > this routine to be undefined for UP.  I have attached the patch for 2.6.1
 > > > below to return 0 for rwlock_is_locked( ) on UP systems.
 > > > Please let me know.
 > > 
 > > I consider any user of this on UP to be broken, just like UP use of
 > > spin_is_locked() is always a bug..... better a compiletime bug than a
 > > runtime bug I guess...
 > 
 > Then maybe a #error explaining this is in order ?

So, if there is a function

void foo_locked(struct bar *obj)
{
    /* check that we are called with obj's lock held */
    BUG_ON(!rwlock_is_locked(&obj->lock));
    /* proceed with obj. */
}

it should now be changed to the

void foo_locked(struct bar *obj)
{
#ifdef CONFIG_SMP
    BUG_ON(!rwlock_is_locked(&obj->lock));
#endif
    /* proceed with obj. */
}

?

 > 
 > - Joe
 > 

Nikita.

 >