[PATCH] staging: lustre: fix lock imbalance

From: Joshua Clayton
Date: Sun Dec 27 2015 - 00:09:15 EST


nrs_resource_put_safe() might hold a lock one one struct
while operating on the other.
There are 2 levels of structures.
Use nrs_policy_put(), which has locking baked in.

sparse gives the following warning:
drivers/staging/lustre//lustre/ptlrpc/nrs.c:498:39:
warning: context imbalance in 'nrs_resource_put_safe' -
different lock contexts for basic block
---
drivers/staging/lustre/lustre/ptlrpc/nrs.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/staging/lustre/lustre/ptlrpc/nrs.c b/drivers/staging/lustre/lustre/ptlrpc/nrs.c
index 7044e1f..9028b12 100644
--- a/drivers/staging/lustre/lustre/ptlrpc/nrs.c
+++ b/drivers/staging/lustre/lustre/ptlrpc/nrs.c
@@ -496,18 +496,9 @@ static void nrs_resource_put_safe(struct ptlrpc_nrs_resource **resp)
}

for (i = 0; i < NRS_RES_MAX; i++) {
- if (pols[i] == NULL)
- continue;
-
- if (nrs == NULL) {
- nrs = pols[i]->pol_nrs;
- spin_lock(&nrs->nrs_lock);
- }
- nrs_policy_put_locked(pols[i]);
+ if (pols[i])
+ nrs_policy_put(pols[i]);
}
-
- if (nrs != NULL)
- spin_unlock(&nrs->nrs_lock);
}

/**
--
2.6.4

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