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Message-ID: <20230719134314.GA7590@ubuntu>
Date: Wed, 19 Jul 2023 06:43:14 -0700
From: Sumitra Sharma <sumitraartsy@...il.com>
To: Patrik Jakobsson <patrik.r.jakobsson@...il.com>,
David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
Ira Weiny <ira.weiny@...el.com>,
Fabio <fmdefrancesco@...il.com>, Deepak R Varma <drv@...lo.com>,
Sumitra Sharma <sumitraartsy@...il.com>,
Alison Schofield <alison.schofield@...el.com>
Subject: [PATCH] Remove unnecessary calls to kmap{,_local_page}() when
acquiring pages using GFP_DMA32.
The GFP_DMA32 uses the DMA32 zone to satisfy the allocation
requests. Therefore, pages allocated with GFP_DMA32 cannot
come from Highmem.
Avoid using calls to kmap() / kunmap() as the kmap() is being
deprecated [1].
Avoid using calls to kmap_local_page() / kunmap_local() as the
code does not depends on the implicit disable of migration of
local mappings and is, in fact, an unnecessary overhead for
the main code [2].
Hence, use a plain page_address() directly in the
psb_mmu_alloc_pd function.
[1]: https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com/
[2]: https://lwn.net/Articles/836503/
Suggested-by: Ira Weiny <ira.weiny@...el.com>
Signed-off-by: Sumitra Sharma <sumitraartsy@...il.com>
---
drivers/gpu/drm/gma500/mmu.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/gma500/mmu.c b/drivers/gpu/drm/gma500/mmu.c
index a70b01ccdf70..1a44dd062fd1 100644
--- a/drivers/gpu/drm/gma500/mmu.c
+++ b/drivers/gpu/drm/gma500/mmu.c
@@ -184,20 +184,15 @@ struct psb_mmu_pd *psb_mmu_alloc_pd(struct psb_mmu_driver *driver,
pd->invalid_pte = 0;
}
- v = kmap_local_page(pd->dummy_pt);
+ v = page_address(pd->dummy_pt);
for (i = 0; i < (PAGE_SIZE / sizeof(uint32_t)); ++i)
v[i] = pd->invalid_pte;
- kunmap_local(v);
-
- v = kmap_local_page(pd->p);
+ v = page_address(pd->p);
for (i = 0; i < (PAGE_SIZE / sizeof(uint32_t)); ++i)
v[i] = pd->invalid_pde;
- kunmap_local(v);
-
- clear_page(kmap(pd->dummy_page));
- kunmap(pd->dummy_page);
+ clear_page(page_address(pd->dummy_page));
pd->tables = vmalloc_user(sizeof(struct psb_mmu_pt *) * 1024);
if (!pd->tables)
--
2.25.1
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