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Date: Thu, 17 Jan 2019 09:22:09 -0600 From: Jassi Brar <jassisinghbrar@...il.com> To: CK Hu <ck.hu@...iatek.com> Cc: Matthias Brugger <matthias.bgg@...il.com>, Houlong Wei <houlong.wei@...iatek.com>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com Subject: Re: [PATCH 1/3] mailbox: Add ability for clients to abort data in channel On Thu, Jan 17, 2019 at 2:00 AM CK Hu <ck.hu@...iatek.com> wrote: > > Hi, Jassi: > > On Wed, 2019-01-16 at 10:22 -0600, Jassi Brar wrote: > > On Tue, Jan 15, 2019 at 11:07 PM CK Hu <ck.hu@...iatek.com> wrote: > > > > > > This patch supplies a new framework API, mbox_abort_channel(), and > > > a new controller interface, abort_data(). > > > > > > For some client's application, it need to clean up the data in channel > > > but keep the channel so it could send data to channel later. > > > > > > Signed-off-by: CK Hu <ck.hu@...iatek.com> > > > --- > > > drivers/mailbox/mailbox.c | 23 +++++++++++++++++++++++ > > > include/linux/mailbox_client.h | 1 + > > > include/linux/mailbox_controller.h | 4 ++++ > > > 3 files changed, 28 insertions(+) > > > > > > diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c > > > index c6a7d4582dc6..281647162c76 100644 > > > --- a/drivers/mailbox/mailbox.c > > > +++ b/drivers/mailbox/mailbox.c > > > @@ -428,6 +428,29 @@ struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl, > > > } > > > EXPORT_SYMBOL_GPL(mbox_request_channel_byname); > > > > > > +/** > > > + * mbox_abort_channel - The client abort all data in a mailbox > > > + * channel by this call. > > > + * @chan: The mailbox channel to be aborted. > > > + */ > > > +void mbox_abort_channel(struct mbox_chan *chan) > > > +{ > > > + unsigned long flags; > > > + > > > + if (!chan || !chan->cl) > > > + return; > > > + > > > + if (chan->mbox->ops->abort_data) > > > + chan->mbox->ops->abort_data(chan); > > > + > > > + /* The queued TX requests are simply aborted, no callbacks are made */ > > > + spin_lock_irqsave(&chan->lock, flags); > > > + chan->cl = NULL; > > > + chan->active_req = NULL; > > > + spin_unlock_irqrestore(&chan->lock, flags); > > > +} > > > > > Why not just release and then request channel again ? > > mbox_abort_channel() is just a copy of mbox_free_channel() and if the > > abort can sleep, that is more reason to just do that. > > The cursor may change position 300 times in one second, so I still > concern the processing time. Request and free channel looks too heavy to > do 300 times per second. You send data 300Hz, not abort ... which is supposed to be a rare event. And then your shutdown/startup is currently empty, while abort isn't quite lightweight. > Conceptually, I just want to clean up the > channel rather than free and request it, so they are somewhat different. > I say it may sleep because mbox_abort_channel() is a copy of > mbox_free_channel(). I could change it to 'must not sleep' because > Mediatek controller does not sleep in abort callback. > No please. Just use the shutdown/startup. Thanks.
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