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stm class: Fix locking in unbinding policy path
Right now, if stm device removal has to unbind from a policy (that is, an stm device that has STP policy, gets removed), it will trigger a nested lock on the stm device's policy mutex. This patch fixes the problem by moving the locking from the policy unbinding to policy removal (configfs path), where it's actually needed; the other caller of the policy unbinding function already takes the mutex around the call. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
042d4460b5
commit
4c127fd16e
1 changed files with 15 additions and 3 deletions
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@ -272,13 +272,17 @@ void stp_policy_unbind(struct stp_policy *policy)
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{
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struct stm_device *stm = policy->stm;
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/*
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* stp_policy_release() will not call here if the policy is already
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* unbound; other users should not either, as no link exists between
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* this policy and anything else in that case
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*/
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if (WARN_ON_ONCE(!policy->stm))
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return;
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mutex_lock(&stm->policy_mutex);
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stm->policy = NULL;
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mutex_unlock(&stm->policy_mutex);
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lockdep_assert_held(&stm->policy_mutex);
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stm->policy = NULL;
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policy->stm = NULL;
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stm_put_device(stm);
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@ -287,8 +291,16 @@ void stp_policy_unbind(struct stp_policy *policy)
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static void stp_policy_release(struct config_item *item)
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{
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struct stp_policy *policy = to_stp_policy(item);
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struct stm_device *stm = policy->stm;
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/* a policy *can* be unbound and still exist in configfs tree */
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if (!stm)
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return;
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mutex_lock(&stm->policy_mutex);
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stp_policy_unbind(policy);
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mutex_unlock(&stm->policy_mutex);
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kfree(policy);
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}
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