LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Ankit Jindal <ankit.jindal@linaro.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Hans J. Koch" <hjk@hansjkoch.de>,
	"patches@apm.com" <patches@apm.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Tushar Jagad" <tushar.jagad@linaro.org>,
	"Russell King - ARM Linux" <linux@arm.linux.org.uk>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"Guenter Roeck" <linux@roeck-us.net>,
	"Varka Bhadram" <varkabhadram@gmail.com>,
	"Kumar Gala" <galak@codeaurora.org>,
	"Anup Patel" <anup@brainfault.org>,
	"Andreas Färber" <afaerber@suse.de>
Subject: Re: [PATCH v5 2/6] uio: Add new UIO_MEM_PHYS_CACHE type for mem regions
Date: Mon, 8 Dec 2014 18:13:28 +0530	[thread overview]
Message-ID: <CAPTm99WWk6XZnEjwjiDoxxGZdR6WccFXZBAjOfpWNq1dWrBfjw@mail.gmail.com> (raw)
In-Reply-To: <20141127000147.GC5313@kroah.com>

On 27 November 2014 at 05:31, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Mon, Nov 17, 2014 at 04:06:08PM +0530, Ankit Jindal wrote:
>> Currently, three types of mem regions are supported: UIO_MEM_PHYS,
>> UIO_MEM_LOGICAL and UIO_MEM_VIRTUAL. Among these UIO_MEM_PHYS helps
>> UIO driver export physcial memory to user space as non-cacheable
>> user memory. Typcially memory-mapped registers of a device are exported
>> to user space as UIO_MEM_PHYS type mem region. The UIO_MEM_PHYS type
>> is not efficient if dma-capable devices are capable of maintaining coherency
>> with CPU caches.
>
> Not efficient in what way?
Sorry, I will rephrase this.
>
>> This patch adds new type UIO_MEM_PHYS_CACHE for mem regions to enable
>> cacheable access to physical memory from user space.
>>
>> Signed-off-by: Ankit Jindal <ankit.jindal@linaro.org>
>> Signed-off-by: Tushar Jagad <tushar.jagad@linaro.org>
>> ---
>>  drivers/uio/uio.c          |   11 ++++++++---
>>  include/linux/uio_driver.h |    1 +
>>  2 files changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
>> index 97e6444..120a84b 100644
>> --- a/drivers/uio/uio.c
>> +++ b/drivers/uio/uio.c
>> @@ -644,7 +644,7 @@ static const struct vm_operations_struct uio_physical_vm_ops = {
>>  #endif
>>  };
>>
>> -static int uio_mmap_physical(struct vm_area_struct *vma)
>> +static int uio_mmap_physical(struct vm_area_struct *vma, bool cacheable)
>
> I despise "bool" flags in a function, as they don't give any idea of
> what is going on when you see the function being called.  Please create
> a new function that does this properly, with a correct name, if it's
> needed.
Sure, will take care of this in next revision.
>
> thanks,
>
> greg k-h
Thanks,
Ankit

  reply	other threads:[~2014-12-08 12:43 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-17 10:36 [PATCH v5 0/6] UIO driver for APM X-Gene QMTM Ankit Jindal
2014-11-17 10:36 ` [PATCH v5 1/6] uio: code style cleanup Ankit Jindal
2014-11-17 10:36 ` [PATCH v5 2/6] uio: Add new UIO_MEM_PHYS_CACHE type for mem regions Ankit Jindal
2014-11-27  0:01   ` Greg Kroah-Hartman
2014-12-08 12:43     ` Ankit Jindal [this message]
2014-11-17 10:36 ` [PATCH v5 3/6] Documentation: Update documentation for UIO_MEM_PHYS_CACHE Ankit Jindal
2014-11-17 10:36 ` [PATCH v5 4/6] uio: Add X-Gene QMTM UIO driver Ankit Jindal
2014-11-17 10:36 ` [PATCH v5 5/6] Documentation: dt-bindings: Add binding info for " Ankit Jindal
2014-11-17 10:43   ` Andreas Färber
2014-11-17 11:17   ` Arnd Bergmann
2014-11-18  9:29     ` Ankit Jindal
2014-11-18 13:10       ` Arnd Bergmann
2014-12-08 12:42         ` Ankit Jindal
2014-12-08 17:15           ` Rob Herring
2014-12-09  6:33             ` Ankit Jindal
2014-11-17 10:36 ` [PATCH v5 6/6] MAINTAINERS: Add entry for APM " Ankit Jindal

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAPTm99WWk6XZnEjwjiDoxxGZdR6WccFXZBAjOfpWNq1dWrBfjw@mail.gmail.com \
    --to=ankit.jindal@linaro.org \
    --cc=afaerber@suse.de \
    --cc=anup@brainfault.org \
    --cc=devicetree@vger.kernel.org \
    --cc=galak@codeaurora.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=hjk@hansjkoch.de \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@arm.linux.org.uk \
    --cc=linux@roeck-us.net \
    --cc=patches@apm.com \
    --cc=robh+dt@kernel.org \
    --cc=tushar.jagad@linaro.org \
    --cc=varkabhadram@gmail.com \
    --subject='Re: [PATCH v5 2/6] uio: Add new UIO_MEM_PHYS_CACHE type for mem regions' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).