iommu.lists.linux-foundation.org archive mirror
 help / color / mirror / Atom feed
From: Arend Van Spriel via iommu <iommu@lists.linux-foundation.org>
To: Christoph Hellwig <hch@lst.de>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <maxime.ripard@bootlin.com>,
	Sean Paul <sean@poorly.run>,  David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel@ffwll.ch>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Ian Abbott <abbotti@mev.co.uk>,
	 H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: devel@driverdev.osuosl.org, linux-s390@vger.kernel.org,
	Intel Linux Wireless <linuxwifi@intel.com>,
	linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
	intel-gfx@lists.freedesktop.org, linux-wireless@vger.kernel.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-mm@kvack.org, iommu@lists.linux-foundation.org,
	"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
	linux-media@vger.kernel.org
Subject: Re: use exact allocation for dma coherent memory
Date: Tue, 2 Jul 2019 11:48:44 +0200	[thread overview]
Message-ID: <74eb9d99-6aa6-d1ad-e66d-6cc9c496b2f3@broadcom.com> (raw)
In-Reply-To: <20190701084833.GA22927@lst.de>



On 7/1/2019 10:48 AM, Christoph Hellwig wrote:
> On Fri, Jun 14, 2019 at 03:47:10PM +0200, Christoph Hellwig wrote:
>> Switching to a slightly cleaned up alloc_pages_exact is pretty easy,
>> but it turns out that because we didn't filter valid gfp_t flags
>> on the DMA allocator, a bunch of drivers were passing __GFP_COMP
>> to it, which is rather bogus in too many ways to explain.  Arm has
>> been filtering it for a while, but this series instead tries to fix
>> the drivers and warn when __GFP_COMP is passed, which makes it much
>> larger than just adding the functionality.
> 
> Dear driver maintainers,
> 
> can you look over the patches touching your drivers, please?  I'd
> like to get as much as possible of the driver patches into this
> merge window, so that it can you through your maintainer trees.

You made me look ;-) Actually not touching my drivers so I'm off the 
hook. However, I was wondering if drivers could know so I decided to 
look into the DMA-API.txt documentation which currently states:

"""
The flag parameter (dma_alloc_coherent() only) allows the caller to
specify the ``GFP_`` flags (see kmalloc()) for the allocation (the
implementation may choose to ignore flags that affect the location of
the returned memory, like GFP_DMA).
"""

I do expect you are going to change that description as well now that 
you are going to issue a warning on __GFP_COMP. Maybe include that in 
patch 15/16 where you introduce that warning.

Regards,
Arend
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2019-07-02 15:13 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-14 13:47 use exact allocation for dma coherent memory Christoph Hellwig
2019-06-14 13:47 ` [PATCH 01/16] media: videobuf-dma-contig: use dma_mmap_coherent Christoph Hellwig
2019-06-14 13:47 ` [PATCH 02/16] drm/ati_pcigart: stop using drm_pci_alloc Christoph Hellwig
2019-06-14 13:47 ` [PATCH 03/16] drm/i915: " Christoph Hellwig
2019-06-14 16:45   ` [Intel-gfx] " Ville Syrjälä
2019-06-14 13:47 ` [PATCH 04/16] drm: move drm_pci_{alloc,free} to drm_legacy Christoph Hellwig
2019-06-14 13:47 ` [PATCH 05/16] drm: don't mark pages returned from drm_pci_alloc reserved Christoph Hellwig
2019-06-14 13:47 ` [PATCH 06/16] drm: don't pass __GFP_COMP to dma_alloc_coherent in drm_pci_alloc Christoph Hellwig
2019-06-14 13:47 ` [PATCH 07/16] IB/hfi1: stop passing bogus gfp flags arguments to dma_alloc_coherent Christoph Hellwig
2019-06-14 13:47 ` [PATCH 08/16] IB/qib: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 09/16] cnic: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 10/16] iwlwifi: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 11/16] s390/ism: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 12/16] staging/comedi: mark as broken Christoph Hellwig
2019-06-14 14:02   ` Greg KH
2019-06-14 14:48     ` Christoph Hellwig
2019-06-14 15:30       ` Greg KH
2019-06-14 15:34         ` Christoph Hellwig
2019-06-17 13:15           ` Ian Abbott
2019-06-14 13:47 ` [PATCH 13/16] mm: rename alloc_pages_exact_nid to alloc_pages_exact_node Christoph Hellwig
2019-06-14 13:47 ` [PATCH 14/16] mm: use alloc_pages_exact_node to implement alloc_pages_exact Christoph Hellwig
2019-06-14 13:47 ` [PATCH 15/16] dma-mapping: clear __GFP_COMP in dma_alloc_attrs Christoph Hellwig
2019-06-14 13:47 ` [PATCH 16/16] dma-mapping: use exact allocation in dma_alloc_contiguous Christoph Hellwig
2019-06-14 14:15   ` David Laight
2019-06-14 14:50     ` 'Christoph Hellwig'
2019-06-14 15:01       ` David Laight
2019-06-14 15:05         ` 'Christoph Hellwig'
2019-06-14 15:05       ` Robin Murphy
2019-06-14 15:08         ` 'Christoph Hellwig'
2019-06-14 15:16         ` David Laight
2019-06-17  8:21 ` use exact allocation for dma coherent memory Dan Carpenter
2019-06-17  8:33   ` Christoph Hellwig
2019-06-19 16:29     ` Jason Gunthorpe
2019-06-20 10:51       ` Christoph Hellwig
2019-07-01  8:48 ` Christoph Hellwig
2019-07-02  9:48   ` Arend Van Spriel via iommu [this message]
2019-07-08 18:43     ` Christoph Hellwig

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=74eb9d99-6aa6-d1ad-e66d-6cc9c496b2f3@broadcom.com \
    --to=iommu@lists.linux-foundation.org \
    --cc=abbotti@mev.co.uk \
    --cc=airlied@linux.ie \
    --cc=arend.vanspriel@broadcom.com \
    --cc=daniel@ffwll.ch \
    --cc=devel@driverdev.osuosl.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=hch@lst.de \
    --cc=hsweeten@visionengravers.com \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=jani.nikula@linux.intel.com \
    --cc=joonas.lahtinen@linux.intel.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linuxwifi@intel.com \
    --cc=maarten.lankhorst@linux.intel.com \
    --cc=maxime.ripard@bootlin.com \
    --cc=netdev@vger.kernel.org \
    --cc=rodrigo.vivi@intel.com \
    --cc=sean@poorly.run \
    /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;
as well as URLs for NNTP newsgroup(s).