Messages in this thread | | | Date | Wed, 26 Sep 2012 16:25:22 +0530 | Subject | Re: [PATCH 3/3] DMA: PL330: Balance module remove function with probe | From | Inderpal Singh <> |
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On 26 September 2012 15:02, Jassi Brar <jassisinghbrar@gmail.com> wrote: > On Wed, Sep 26, 2012 at 12:11 PM, Inderpal Singh > <inderpal.singh@linaro.org> wrote: > >> How about conditionally DMA_TERMINATE_ALL and free resources like below ? >> >> @@ -3017,9 +3017,11 @@ static int __devexit pl330_remove(struct >> amba_device *adev) >> /* Remove the channel */ >> list_del(&pch->chan.device_node); >> >> - /* Flush the channel */ >> - pl330_control(&pch->chan, DMA_TERMINATE_ALL, 0); >> - pl330_free_chan_resources(&pch->chan); >> + if (pch->chan.client_count != 0) { >> + /* Flush the channel */ >> + pl330_control(&pch->chan, DMA_TERMINATE_ALL, 0); >> + pl330_free_chan_resources(&pch->chan); >> + } >> } >> > It is perfectly safe to flush the channels that have client_count == 0 > as well. Which is already the case.
As per my understanding, if client_count ==0, It may mean following:
1. This channel was never allocated to any client. Hence alloc_chan_resources was not done for it. So, no need to flush and free resources if it was never allocated at the first place. If we free_chan_resources, it will not be balanced against alloc_chan_resources. Scenario: insmod and then rmmod.
Or,
2. The channel was allocated to some client, alloc_chan_resource was done, the work for the client is completed and free_chan_resources was performed. Now since resources have already been freed, no need to flush and free_chan_resources again in remove.
The whole idea of this patch is to balance alloc_chan_resources and free_chan_resources.
Thanks, Inder
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