Re: [HPDD-discuss] [PATCH 4/4] Staging: lustre: sparse lock warning fix
On 2015/05/20, 1:42 PM, "Dan Carpenter" <dan.carpenter(a)oracle.com> wrote:
In Smatch, it the equivalent warning is turned off by default because
there are too many false positives, but you can enable it with the
--spammy flag.
kchecker --spammy drivers/staging/lustre/lustre/ptlrpc/nrs.c
drivers/staging/lustre/lustre/ptlrpc/nrs.c:512 nrs_resource_put_safe()
warn: 'spin_lock:&nrs->nrs_lock' is sometimes locked here and sometimes
unlocked.
Would this be happier with something like:
for (i = 0; i < NRS_RES_MAX; i++) {
if (pols[i] == NULL)
continue;
if (nrs == NULL) {
nrs = pols[i]->pol_nrs;
if (likely(nrs != NULL)) /* make sparse happy */
spin_lock(&nrs->nrs_lock);
}
nrs_policy_put_locked(pols[i]);
}
if (nrs != NULL)
spin_unlock(&nrs->nrs_lock);
so that the "if" conditions are the same? The code definitely doesn't
have a bug, because the lock is only locked once when nrs is first set,
and only unlocked if it is set. Or is there a comment to put there that
will quiet the static checker?
Cheers, Andreas
--
Andreas Dilger
Lustre Software Architect
Intel High Performance Data Division