Re: [PATCH] dma: zynqmp_dma: Initialize descriptor list after freeing during reset

[Vinod Koul]

On 02-05-20, 15:00, RafaÅ Hibner wrote:
> Hello Vinod,
> 
> On 02.05.2020 14:32, Vinod Koul wrote:
> > Would it not be better to use list_del_init() where we delete it rather
> > than do the init here?
> >
> 
> It is not a problem of list element itself not being initialized.
> The problem is that during fault conditions (zynqmp_dma_reset) all
> elements are moved to free list. List head however is not reinitialized.
> 
> In normal flow elements are removed by list_del and resubmitted to
> free list with zynqmp_dma_free_descriptor.
> 
> static void zynqmp_dma_chan_desc_cleanup(struct zynqmp_dma_chan *chan)
> {
> ÂÂÂ ...
> ÂÂÂ list_for_each_entry_safe(desc, next, &chan->done_list, node) {
> ÂÂÂÂÂÂÂ ...
> ÂÂÂÂÂÂÂ list_del(&desc->node);
> ÂÂÂÂÂÂÂ ...
> ÂÂÂÂÂÂÂ zynqmp_dma_free_descriptor(chan, desc);
> ÂÂÂ }
> }
> 
> The zynqmp_dma_free_descriptor does not delete elements from the
> list by itself.
> I am not he author of this driver so I fixed it by
> doing non intrusive changes.
> 
> Anyways, I do not see how using list_del_init would fix the bug.

Looking at this, i think it would make sense to do list_splice_init()
before we send the list to be freed.

Radhey/Appana are cced, they should test this.

-- 
~Vinod