Hello Peng Ma,
Commit b092529e0aa0 ("dmaengine: fsl-qdma: Add qDMA controller driver
for Layerscape SoCs") from Oct 30, 2018 (linux-next), leads to the
following Smatch static checker warning:
drivers/dma/fsl-qdma.c:331 fsl_qdma_free_chan_resources()
error: we previously assumed 'fsl_queue->comp_pool' could be null (see line 324)
drivers/dma/fsl-qdma.c
309 static void fsl_qdma_free_chan_resources(struct dma_chan *chan)
310 {
311 struct fsl_qdma_chan *fsl_chan = to_fsl_qdma_chan(chan);
312 struct fsl_qdma_queue *fsl_queue = fsl_chan->queue;
313 struct fsl_qdma_engine *fsl_qdma = fsl_chan->qdma;
314 struct fsl_qdma_comp *comp_temp, *_comp_temp;
315 unsigned long flags;
316 LIST_HEAD(head);
317
318 spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
319 vchan_get_all_descriptors(&fsl_chan->vchan, &head);
320 spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
321
322 vchan_dma_desc_free_list(&fsl_chan->vchan, &head);
323
324 if (!fsl_queue->comp_pool && !fsl_queue->desc_pool)
This should probably be || instead of &&.
325 return;
326
327 list_for_each_entry_safe(comp_temp, _comp_temp,
328 &fsl_queue->comp_used, list) {
329 dma_pool_free(fsl_queue->comp_pool,
^^^^^^^^^^^^^^^^^^^^
If only one is free but not the other then it leads to an Oops.
330 comp_temp->virt_addr,
--> 331 comp_temp->bus_addr);
332 dma_pool_free(fsl_queue->desc_pool,
^^^^^^^^^^^^^^^^^^^^
333 comp_temp->desc_virt_addr,
334 comp_temp->desc_bus_addr);
335 list_del(&comp_temp->list);
336 kfree(comp_temp);
337 }
regards,
dan carpenter
