From: Andrew Morton <akpm@linux-foundation.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
dan.j.williams@intel.com, jglisse@redhat.com,
ldufour@linux.vnet.ibm.com
Subject: Re: [PATCH] mm/dev_pfn: Exclude MEMORY_DEVICE_PRIVATE while computing virtual address
Date: Fri, 17 May 2019 14:50:50 -0700 [thread overview]
Message-ID: <20190517145050.2b6b0afdaab5c3c69a4b153e@linux-foundation.org> (raw)
In-Reply-To: <1558089514-25067-1-git-send-email-anshuman.khandual@arm.com>
On Fri, 17 May 2019 16:08:34 +0530 Anshuman Khandual <anshuman.khandual@arm.com> wrote:
> The presence of struct page does not guarantee linear mapping for the pfn
> physical range. Device private memory which is non-coherent is excluded
> from linear mapping during devm_memremap_pages() though they will still
> have struct page coverage. Just check for device private memory before
> giving out virtual address for a given pfn.
I was going to give my standard "what are the user-visible runtime
effects of this change?", but...
> All these helper functions are all pfn_t related but could not figure out
> another way of determining a private pfn without looking into it's struct
> page. pfn_t_to_virt() is not getting used any where in mainline kernel.Is
> it used by out of tree drivers ? Should we then drop it completely ?
Yeah, let's kill it.
But first, let's fix it so that if someone brings it back, they bring
back a non-buggy version.
So... what (would be) the user-visible runtime effects of this change?
next prev parent reply other threads:[~2019-05-17 21:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-17 10:38 Anshuman Khandual
2019-05-17 21:50 ` Andrew Morton [this message]
2019-05-20 5:37 ` Anshuman Khandual
2019-05-20 19:00 ` Dan Williams
2019-05-20 19:27 ` Jerome Glisse
2019-05-20 19:33 ` Dan Williams
2019-05-21 2:08 ` Anshuman Khandual
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=20190517145050.2b6b0afdaab5c3c69a4b153e@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=anshuman.khandual@arm.com \
--cc=dan.j.williams@intel.com \
--cc=jglisse@redhat.com \
--cc=ldufour@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox