linux-kernel - [PATCH v2] drm/etnaviv: Clear the __GFP_HIGHMEM bit in GFP

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Message-Id: <20240807013328.2795300-1-xiaolei.wang@windriver.com>
Date: Wed,  7 Aug 2024 09:33:28 +0800
From: Xiaolei Wang <xiaolei.wang@...driver.com>
To: l.stach@...gutronix.de, linux+etnaviv@...linux.org.uk,
        christian.gmeiner@...il.com, airlied@...il.com, daniel@...ll.ch
Cc: etnaviv@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] drm/etnaviv: Clear the __GFP_HIGHMEM bit in GFP_HIGHUSER with 32 address

GFP_HIGHUSER is a combination of GFP_USER | __GFP_HIGHMEM.
Only the highmem part is incompatible with DMA32. Reserve
GFP_USER bit here, as the driver allocated buffers might
be mapped to userspace.

Fixes: b72af445cd38 ("drm/etnaviv: request pages from DMA32 zone when needed")
Signed-off-by: Xiaolei Wang <xiaolei.wang@...driver.com>
---
change log

v1:
  https://patchwork.kernel.org/project/dri-devel/patch/20240806104733.2018783-1-xiaolei.wang@windriver.com/

v2:
  Modify the issue of not retaining GFP_USER in v1 and update the commit log.

 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 7c7f97793ddd..0e6bdf2d028b 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -844,8 +844,10 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
 	 * request pages for our SHM backend buffers from the DMA32 zone to
 	 * hopefully avoid performance killing SWIOTLB bounce buffering.
 	 */
-	if (dma_addressing_limited(gpu->dev))
+	if (dma_addressing_limited(gpu->dev)) {
 		priv->shm_gfp_mask |= GFP_DMA32;
+		priv->shm_gfp_mask &= ~__GFP_HIGHMEM;
+	}
 
 	/* Create buffer: */
 	ret = etnaviv_cmdbuf_init(priv->cmdbuf_suballoc, &gpu->buffer,
-- 
2.25.1