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Message-Id: <20201103095859.836711767@linutronix.de>
Date: Tue, 03 Nov 2020 10:27:44 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Linus Torvalds <torvalds@...uxfoundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Paul McKenney <paulmck@...nel.org>,
Christoph Hellwig <hch@....de>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
VMware Graphics <linux-graphics-maintainer@...are.com>,
Roland Scheidegger <sroland@...are.com>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
dri-devel@...ts.freedesktop.org,
Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
Alexander Viro <viro@...iv.linux.org.uk>,
Benjamin LaHaise <bcrl@...ck.org>,
linux-fsdevel@...r.kernel.org, linux-aio@...ck.org,
Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>, linux-btrfs@...r.kernel.org,
x86@...nel.org, Vineet Gupta <vgupta@...opsys.com>,
linux-snps-arc@...ts.infradead.org,
Russell King <linux@...linux.org.uk>,
Arnd Bergmann <arnd@...db.de>,
linux-arm-kernel@...ts.infradead.org, linux-csky@...r.kernel.org,
Michal Simek <monstr@...str.eu>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
linux-mips@...r.kernel.org, Nick Hu <nickhu@...estech.com>,
Greentime Hu <green.hu@...il.com>,
Vincent Chen <deanbo422@...il.com>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
linuxppc-dev@...ts.ozlabs.org,
"David S. Miller" <davem@...emloft.net>,
sparclinux@...r.kernel.org, Chris Zankel <chris@...kel.net>,
Max Filippov <jcmvbkbc@...il.com>,
linux-xtensa@...ux-xtensa.org, Ingo Molnar <mingo@...nel.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Christian Koenig <christian.koenig@....com>,
Huang Rui <ray.huang@....com>,
Dave Airlie <airlied@...hat.com>,
Gerd Hoffmann <kraxel@...hat.com>,
virtualization@...ts.linux-foundation.org,
spice-devel@...ts.freedesktop.org, Ben Skeggs <bskeggs@...hat.com>,
nouveau@...ts.freedesktop.org,
Jani Nikula <jani.nikula@...ux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@...el.com>,
intel-gfx@...ts.freedesktop.org
Subject: [patch V3 32/37] drm/vmgfx: Replace kmap_atomic()
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@...utronix.de>
Cc: VMware Graphics <linux-graphics-maintainer@...are.com>
Cc: Roland Scheidegger <sroland@...are.com>
Cc: David Airlie <airlied@...ux.ie>
Cc: Daniel Vetter <daniel@...ll.ch>
Cc: dri-devel@...ts.freedesktop.org
---
V3: New patch
---
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;
}
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