From: Mauro Carvalho Chehab <mchehab@s-opensource.com>
To: Michael Ira Krufky <mkrufky@linuxtv.org>, Antti Palosaari <crope@iki.fi>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH 00/26] Don't use stack for DMA transers on dvb-usb drivers
Date: Tue, 11 Oct 2016 07:12:04 -0300 [thread overview]
Message-ID: <20161011071204.6096efbb@vento.lan> (raw)
In-Reply-To: <CAOcJUbxv_jm4SVtPYpm=+jhFh_0cFx4-h_N8gZoQ9r2+nqULOg@mail.gmail.com>
Em Mon, 10 Oct 2016 07:44:53 -0400
Michael Ira Krufky <mkrufky@linuxtv.org> escreveu:
> Antti makes a very good point. If we consider a situation where we
> are streaming data while concurrently checking frontend status and
> polling for IR codes, some locking will certainly be required in all
> of these drivers.
>
> -Mike Krufky
>
> On Mon, Oct 10, 2016 at 7:24 AM, Antti Palosaari <crope@iki.fi> wrote:
> > Hello
> > If you use usb buffers from the state you will need add lock in order to
> > protect concurrent access to buffer. There may have multiple concurrent
> > operations from rc-polling/demux/frontend. Lets say you are reading ber and
> > it sets data to buffer (state), then context switch to remote controller
> > polling => buffer in state is overwritten, then context is changed back to
> > ber reading and now there is bad data.
Indeed a mutex to protect it is required. I added it and re-submitted
the series, with a few extra patches, fixing issues on some drivers
that are outside dvb-usb.
Feel free to review.
Regards,
Mauro
prev parent reply other threads:[~2016-10-11 10:22 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 17:24 [PATCH 00/26] Don't use stack for DMA transers on dvb-usb drivers Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 01/26] af9005: don't do DMA on stack Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 02/26] cinergyT2-core: " Mauro Carvalho Chehab
2016-10-10 6:39 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 03/26] cinergyT2-core:: handle error code on RC query Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 04/26] cinergyT2-fe: cache stats at cinergyt2_fe_read_status() Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 05/26] cinergyT2-fe: don't do DMA on stack Mauro Carvalho Chehab
2016-10-10 6:39 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 06/26] cxusb: " Mauro Carvalho Chehab
2016-10-10 6:38 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 07/26] dib0700: be sure that dib0700_ctrl_rd() users can do DMA Mauro Carvalho Chehab
2016-10-10 6:38 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 08/26] dib0700_core: don't use stack on I2C reads Mauro Carvalho Chehab
2016-10-10 6:37 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 09/26] dibusb: don't do DMA on stack Mauro Carvalho Chehab
2016-10-10 6:37 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 10/26] dibusb: handle error code on RC query Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 11/26] digitv: don't do DMA on stack Mauro Carvalho Chehab
2016-10-10 6:36 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 12/26] dtt200u-fe: " Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 13/26] dtt200u-fe: handle errors on USB control messages Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 14/26] dtt200u: don't do DMA on stack Mauro Carvalho Chehab
2016-10-10 6:36 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 15/26] dtt200u: handle USB control message errors Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 16/26] dtv5100: : don't do DMA on stack Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 17/26] gp8psk: " Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 18/26] gp8psk: don't go past the buffer size Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 19/26] nova-t-usb2: don't do DMA on stack Mauro Carvalho Chehab
2016-10-10 6:35 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 20/26] pctv452e: " Mauro Carvalho Chehab
2016-10-10 6:35 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 21/26] pctv452e: don't call BUG_ON() on non-fatal error Mauro Carvalho Chehab
2016-10-08 10:11 ` [PATCH v2 " Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 22/26] technisat-usb2: use DMA buffers for I2C transfers Mauro Carvalho Chehab
2016-10-10 6:34 ` Patrick Boettcher
2016-10-07 17:24 ` [PATCH 23/26] dvb-usb: warn if return value for USB read/write routines is not checked Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 24/26] nova-t-usb2: handle error code on RC query Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 25/26] dw2102: return error if su3000_power_ctrl() fails Mauro Carvalho Chehab
2016-10-07 17:24 ` [PATCH 26/26] digitv: handle error code on RC query Mauro Carvalho Chehab
2016-10-10 11:24 ` [PATCH 00/26] Don't use stack for DMA transers on dvb-usb drivers Antti Palosaari
2016-10-10 11:44 ` Michael Ira Krufky
2016-10-11 10:12 ` Mauro Carvalho Chehab [this message]
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