On Sep 12, 2016, at 04:27, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Fri, Sep 09, 2016 at 08:50:35PM +0530, Nayeemahmed Badebade wrote: >> Added __acquires / __releases sparse locking annotations >> to lock_res_and_lock and unlock_res_and_lock functions in >> l_lock.c, to fix below sparse warnings: >> >> l_lock.c:47:22: warning: context imbalance in 'lock_res_and_lock' - wrong count at exit >> l_lock.c:62:6: warning: context imbalance in 'unlock_res_and_lock' - unexpected unlock >> >> Signed-off-by: Nayeemahmed Badebade <itachi.opsrc@xxxxxxxxx> >> --- >> drivers/staging/lustre/lustre/ldlm/l_lock.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/staging/lustre/lustre/ldlm/l_lock.c b/drivers/staging/lustre/lustre/ldlm/l_lock.c >> index ea8840c..c4b9612 100644 >> --- a/drivers/staging/lustre/lustre/ldlm/l_lock.c >> +++ b/drivers/staging/lustre/lustre/ldlm/l_lock.c >> @@ -45,6 +45,8 @@ >> * being an atomic operation. >> */ >> struct ldlm_resource *lock_res_and_lock(struct ldlm_lock *lock) >> + __acquires(&lock->l_lock) >> + __acquires(lock->l_resource) > > Hm, these are tricky, I don't want to take this type of change without > an ack from the lustre developers... The "__acquires(&lock->l_lock)" line here looks correct, along with the corresponding "__releases(&lock->l_lock)" at unlock_res_and_lock(). The problem, however, is that "l_resource" is not a lock, but rather a struct. The call to "lock_res(lock->l_resource)" is actually locking "lr_lock" internally. It would be better to add "__acquires(&res->lr_lock)" at lock_res() and "__releases(&res->lr_lock)" at unlock_res(). That will also forestall any other warnings about an imbalance with lock_res()/unlock_res() or their callsites. Cheers, Andreas _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
