From: Zack Rusin <zackr@vmware.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux-graphics-maintainer <Linux-graphics-maintainer@vmware.com>,
Roland Scheidegger <sroland@vmware.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
DRI Development <dri-devel@lists.freedesktop.org>,
Christian Koenig <christian.koenig@amd.com>,
Huang Rui <ray.huang@amd.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Gerd Hoffmann <kraxel@redhat.com>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"spice-devel@lists.freedesktop.org"
<spice-devel@lists.freedesktop.org>,
Ben Skeggs <bskeggs@redhat.com>,
"nouveau@lists.freedesktop.org" <nouveau@lists.freedesktop.org>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Chris Wilson <chris@chris-wilson.co.uk>,
"intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>
Subject: Re: [patch 2/7] drm/vmgfx: Replace kmap_atomic()
Date: Thu, 4 Mar 2021 18:47:43 +0000 [thread overview]
Message-ID: <66B6DD38-3BE5-4B94-A15C-8A1B1D417754@vmware.com> (raw)
In-Reply-To: <20210303132711.487711828@linutronix.de>
> On Mar 3, 2021, at 08:20, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> From: Thomas Gleixner <tglx@linutronix.de>
>
> There is no reason to disable pagefaults and preemption as a side effect of
> kmap_atomic_prot().
>
> Use kmap_local_page_prot() instead and document the reasoning for the
> mapping usage with the given pgprot.
>
> Remove the NULL pointer check for the map. These functions return a valid
> address for valid pages and the return was bogus anyway as it would have
> left preemption and pagefaults disabled.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
> Cc: Roland Scheidegger <sroland@vmware.com>
> Cc: Zack Rusin <zackr@vmware.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> ---
> drivers/gpu/drm/vmwgfx/vmwgfx_blit.c | 30 ++++++++++++------------------
> 1 file changed, 12 insertions(+), 18 deletions(-)
>
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_blit.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_blit.c
> @@ -375,12 +375,12 @@ static int vmw_bo_cpu_blit_line(struct v
> copy_size = min_t(u32, copy_size, PAGE_SIZE - src_page_offset);
>
> if (unmap_src) {
> - kunmap_atomic(d->src_addr);
> + kunmap_local(d->src_addr);
> d->src_addr = NULL;
> }
>
> if (unmap_dst) {
> - kunmap_atomic(d->dst_addr);
> + kunmap_local(d->dst_addr);
> d->dst_addr = NULL;
> }
>
> @@ -388,12 +388,8 @@ static int vmw_bo_cpu_blit_line(struct v
> if (WARN_ON_ONCE(dst_page >= d->dst_num_pages))
> return -EINVAL;
>
> - d->dst_addr =
> - kmap_atomic_prot(d->dst_pages[dst_page],
> - d->dst_prot);
> - if (!d->dst_addr)
> - return -ENOMEM;
> -
> + d->dst_addr = kmap_local_page_prot(d->dst_pages[dst_page],
> + d->dst_prot);
> d->mapped_dst = dst_page;
> }
>
> @@ -401,12 +397,8 @@ static int vmw_bo_cpu_blit_line(struct v
> if (WARN_ON_ONCE(src_page >= d->src_num_pages))
> return -EINVAL;
>
> - d->src_addr =
> - kmap_atomic_prot(d->src_pages[src_page],
> - d->src_prot);
> - if (!d->src_addr)
> - return -ENOMEM;
> -
> + d->src_addr = kmap_local_page_prot(d->src_pages[src_page],
> + d->src_prot);
> d->mapped_src = src_page;
> }
> diff->do_cpy(diff, d->dst_addr + dst_page_offset,
> @@ -436,8 +428,10 @@ static int vmw_bo_cpu_blit_line(struct v
> *
> * Performs a CPU blit from one buffer object to another avoiding a full
> * bo vmap which may exhaust- or fragment vmalloc space.
> - * On supported architectures (x86), we're using kmap_atomic which avoids
> - * cross-processor TLB- and cache flushes and may, on non-HIGHMEM systems
> + *
> + * On supported architectures (x86), we're using kmap_local_prot() which
> + * avoids cross-processor TLB- and cache flushes. kmap_local_prot() will
> + * either map a highmem page with the proper pgprot on HIGHMEM=y systems or
> * reference already set-up mappings.
> *
> * Neither of the buffer objects may be placed in PCI memory
> @@ -500,9 +494,9 @@ int vmw_bo_cpu_blit(struct ttm_buffer_ob
> }
> out:
> if (d.src_addr)
> - kunmap_atomic(d.src_addr);
> + kunmap_local(d.src_addr);
> if (d.dst_addr)
> - kunmap_atomic(d.dst_addr);
> + kunmap_local(d.dst_addr);
>
> return ret;
> }
Looks good. Thanks.
Reviewed-by: Zack Rusin <zackr@vmware.com>
z
next prev parent reply other threads:[~2021-03-04 18:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 13:20 [patch 0/7] drm, highmem: Cleanup io/kmap_atomic*() usage Thomas Gleixner
2021-03-03 13:20 ` [patch 1/7] drm/ttm: Replace kmap_atomic() usage Thomas Gleixner
2021-03-04 17:42 ` Christian König
2021-03-03 13:20 ` [patch 2/7] drm/vmgfx: Replace kmap_atomic() Thomas Gleixner
2021-03-04 18:47 ` Zack Rusin [this message]
2021-03-05 15:35 ` Roland Scheidegger
2021-03-03 13:20 ` [patch 3/7] highmem: Remove kmap_atomic_prot() Thomas Gleixner
2021-03-03 13:20 ` [patch 4/7] drm/qxl: Replace io_mapping_map_atomic_wc() Thomas Gleixner
2021-03-03 13:20 ` [patch 5/7] drm/nouveau/device: " Thomas Gleixner
2021-03-03 13:20 ` [patch 6/7] drm/i915: " Thomas Gleixner
2021-03-03 13:20 ` [patch 7/7] io-mapping: Remove io_mapping_map_atomic_wc() Thomas Gleixner
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=66B6DD38-3BE5-4B94-A15C-8A1B1D417754@vmware.com \
--to=zackr@vmware.com \
--cc=Linux-graphics-maintainer@vmware.com \
--cc=airlied@linux.ie \
--cc=akpm@linux-foundation.org \
--cc=bskeggs@redhat.com \
--cc=chris@chris-wilson.co.uk \
--cc=christian.koenig@amd.com \
--cc=daniel@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=jani.nikula@linux.intel.com \
--cc=joonas.lahtinen@linux.intel.com \
--cc=kraxel@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=nouveau@lists.freedesktop.org \
--cc=ray.huang@amd.com \
--cc=rodrigo.vivi@intel.com \
--cc=spice-devel@lists.freedesktop.org \
--cc=sroland@vmware.com \
--cc=tglx@linutronix.de \
--cc=virtualization@lists.linux-foundation.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;
as well as URLs for NNTP newsgroup(s).