Merge "msm: camera: reqmgr: Prevent session deadlock" into camera-kernel.lnx.5.0
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zatwierdzone przez
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6f1081755e
@@ -1424,20 +1424,20 @@ static int __cam_req_mgr_process_req(struct cam_req_mgr_core_link *link,
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return -EINVAL;
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}
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mutex_lock(&session->lock);
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/*
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* In case if the wq is scheduled while destroying session
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* the session mutex is already taken and will cause a
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* dead lock. To avoid further processing check link state
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* and exit.
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* During session destroy/unlink the link state is updated and session
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* mutex is released when flushing the workq. In case the wq is scheduled
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* thereafter this API will then check the updated link state and exit
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*/
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spin_lock_bh(&link->link_state_spin_lock);
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if (link->state == CAM_CRM_LINK_STATE_IDLE) {
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spin_unlock_bh(&link->link_state_spin_lock);
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mutex_unlock(&session->lock);
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return -EPERM;
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}
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spin_unlock_bh(&link->link_state_spin_lock);
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mutex_lock(&session->lock);
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in_q = link->req.in_q;
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/*
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* Check if new read index,
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@@ -4460,13 +4460,17 @@ end:
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/**
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* __cam_req_mgr_unlink()
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*
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* @brief : Unlink devices on a link structure from the session
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* @link : Pointer to the link structure
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* @brief : Unlink devices on a link structure from the session
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* This API is to be invoked with session mutex held
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* @session: session of the link
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* @link : Pointer to the link structure
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*
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* @return: 0 for success, negative for failure
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*
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*/
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static int __cam_req_mgr_unlink(struct cam_req_mgr_core_link *link)
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static int __cam_req_mgr_unlink(
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struct cam_req_mgr_core_session *session,
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struct cam_req_mgr_core_link *link)
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{
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int rc;
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@@ -4482,14 +4486,16 @@ static int __cam_req_mgr_unlink(struct cam_req_mgr_core_link *link)
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}
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mutex_lock(&link->lock);
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spin_lock_bh(&link->link_state_spin_lock);
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/* Destroy timer of link */
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crm_timer_exit(&link->watchdog);
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spin_unlock_bh(&link->link_state_spin_lock);
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/* Release session mutex for workq processing */
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mutex_unlock(&session->lock);
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/* Destroy workq of link */
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cam_req_mgr_workq_destroy(&link->workq);
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/* Acquire session mutex after workq flush */
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mutex_lock(&session->lock);
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/* Cleanup request tables and unlink devices */
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__cam_req_mgr_destroy_link_info(link);
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/* Free memory holding data of linked devs */
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@@ -4531,6 +4537,7 @@ int cam_req_mgr_destroy_session(
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goto end;
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}
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mutex_lock(&cam_session->lock);
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if (cam_session->num_links) {
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CAM_DBG(CAM_CRM, "destroy session %x num_active_links %d",
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@@ -4546,7 +4553,7 @@ int cam_req_mgr_destroy_session(
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link->link_hdl);
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/* Ignore return value since session is going away */
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link->is_shutdown = is_shutdown;
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__cam_req_mgr_unlink(link);
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__cam_req_mgr_unlink(cam_session, link);
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__cam_req_mgr_free_link(link);
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}
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}
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@@ -4829,8 +4836,9 @@ int cam_req_mgr_unlink(struct cam_req_mgr_unlink_info *unlink_info)
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rc = -EINVAL;
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goto done;
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}
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rc = __cam_req_mgr_unlink(link);
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mutex_lock(&cam_session->lock);
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rc = __cam_req_mgr_unlink(cam_session, link);
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mutex_unlock(&cam_session->lock);
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/* Free curent link and put back into session's free pool of links */
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__cam_req_mgr_unreserve_link(cam_session, link);
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