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

[RafaÅ Hibner]

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.

Regards, Rafal