linux-kernel - [PATCH v4] drm/etnaviv: Request pages from DMA32 zone on addressing

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Message-Id: <20241001233430.4072268-1-xiaolei.wang@windriver.com>
Date: Wed,  2 Oct 2024 07:34:30 +0800
From: Xiaolei Wang <xiaolei.wang@...driver.com>
To: l.stach@...gutronix.de, sui.jingfeng@...ux.dev,
        christian.gmeiner@...il.com, airlied@...il.com, daniel@...ll.ch,
        linux+etnaviv@...linux.org.uk
Cc: etnaviv@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4] drm/etnaviv: Request pages from DMA32 zone on addressing_limited

Remove __GFP_HIGHMEM when requesting a page from DMA32 zone,
and since all vivante GPUs in the system will share the same
DMA constraints, move the check of whether to get a page from
DMA32 to etnaviv_bind().

Fixes: b72af445cd38 ("drm/etnaviv: request pages from DMA32 zone when needed")
Suggested-by: Sui Jingfeng <sui.jingfeng@...ux.dev>
Signed-off-by: Xiaolei Wang <xiaolei.wang@...driver.com>
Reviewed-by: Christian Gmeiner <cgmeiner@...lia.com>
---
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.

v3:
  Use "priv->shm_gfp_mask = GFP_USER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;"
instead of
  "priv->shm_gfp_mask = GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;"

v4:
  drop the HIGHMEM bit only if dma addressing is limited.

 drivers/gpu/drm/etnaviv/etnaviv_drv.c | 10 ++++++++++
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c |  8 --------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
index 6500f3999c5f..19ec67a5a918 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
@@ -538,6 +538,16 @@ static int etnaviv_bind(struct device *dev)
 	priv->num_gpus = 0;
 	priv->shm_gfp_mask = GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
 
+	/*
+	 * If the GPU is part of a system with DMA addressing limitations,
+	 * request pages for our SHM backend buffers from the DMA32 zone to
+	 * hopefully avoid performance killing SWIOTLB bounce buffering.
+	 */
+	if (dma_addressing_limited(dev)) {
+		priv->shm_gfp_mask |= GFP_DMA32;
+		priv->shm_gfp_mask &= ~__GFP_HIGHMEM;
+	}
+
 	priv->cmdbuf_suballoc = etnaviv_cmdbuf_suballoc_new(drm->dev);
 	if (IS_ERR(priv->cmdbuf_suballoc)) {
 		dev_err(drm->dev, "Failed to create cmdbuf suballocator\n");
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 7c7f97793ddd..5e753dd42f72 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -839,14 +839,6 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
 	if (ret)
 		goto fail;
 
-	/*
-	 * If the GPU is part of a system with DMA addressing limitations,
-	 * 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))
-		priv->shm_gfp_mask |= GFP_DMA32;
-
 	/* Create buffer: */
 	ret = etnaviv_cmdbuf_init(priv->cmdbuf_suballoc, &gpu->buffer,
 				  PAGE_SIZE);
-- 
2.25.1