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Groups > linux.kernel > #1653247
| From | Peter Senna Tschudin <peter.senna@collabora.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC, PATCH] imx: serial: Take tty->files_lock opportunistically |
| Date | 2017-05-30 15:50 +0200 |
| Message-ID | <tMPH4-82d-23@gated-at.bofh.it> (permalink) |
| References | <tMOBj-7lm-3@gated-at.bofh.it> <tMOUG-7tv-25@gated-at.bofh.it> <tMPH3-82d-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, May 30, 2017 at 02:42:13PM +0100, Alan Cox wrote:
I sent a second patch recently:
https://patchwork.kernel.org/patch/9725625/
> > > Fixes: 18a4208826dd0a13eb06de724c86bba2c225f943 ("imx-serial: Reduce
> > > RX DMA startup latency when opening for reading")
> > >
> > > Cc: cphealy@gmail.com
> > > Cc: Peter Senna Tschudin <peter.senna@collabora.com>
> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > Cc: Jiri Slaby <jslaby@suse.com>
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> > > ---
> > >
> > > Not sure if this is the best way to solve the problem (hence the RFC
> > > tag). If anyone has a better idea, or if there's a better fix for this
> > > already, please let me know.
> >
> > IMO, the low level serial drivers shouldn't be accessing
> > tty->tty_files in the first place. Is being opened for write-only that
> > common and is skipping the DMA setup really necessary?
>
> Seconded - the Reduce RX DMA startup latency patch should just be
> reverted (and shouldn't ever IMHO have gotten in).
>
> Not all readers and writers to a tty have a file handle any more anyway,
> so it's not only icky and layer violating it's fundamentally broken
> beyond the locking.
>
> Alan
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[RFC, PATCH] imx: serial: Take tty->files_lock opportunistically Andrey Smirnov <andrew.smirnov@gmail.com> - 2017-05-30 14:40 +0200
Re: [RFC, PATCH] imx: serial: Take tty->files_lock opportunistically Rob Herring <robherring2@gmail.com> - 2017-05-30 15:00 +0200
Re: [RFC, PATCH] imx: serial: Take tty->files_lock opportunistically Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-05-30 15:50 +0200
Re: [RFC, PATCH] imx: serial: Take tty->files_lock opportunistically Peter Senna Tschudin <peter.senna@collabora.com> - 2017-05-30 15:50 +0200
Re: [RFC, PATCH] imx: serial: Take tty->files_lock opportunistically Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-03 16:20 +0200
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