On Mon, 2024-10-28 at 09:04 +1100, NeilBrown wrote: > refcount_t, by design, checks for unwanted situations and provides > warnings. It is rarely useful to have explicit warnings with refcount > usage. > > In this case we have an explicit warning if a refcount_t reaches zero > when decremented. Simply using refcount_dec() will provide a similar > warning and also mark the refcount_t as saturated to avoid any possible > use-after-free. > > This patch drops the warning and uses refcount_dec() instead of > refcount_dec_and_test(). > > Signed-off-by: NeilBrown <neilb@xxxxxxx> > --- > fs/nfsd/filecache.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c > index 1408166222c5..c16671135d17 100644 > --- a/fs/nfsd/filecache.c > +++ b/fs/nfsd/filecache.c > @@ -1050,7 +1050,7 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net, > * the last one however, since we should hold another. > */ > if (nfsd_file_lru_remove(nf)) > - WARN_ON_ONCE(refcount_dec_and_test(&nf->nf_ref)); > + refcount_dec(&nf->nf_ref); The existing code threw a warning when the counter reached 0. Your change will make the potential warning fire later, after we try to put the last reference and the counter goes to -1. That's probably fine as it should happen later in this function either way. > goto wait_for_construction; > } > > > base-commit: 7fa861d5df402b2327f45e0240c1b842f71fec11 Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
