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Message-ID: <20240123221227.868341-1-afd@ti.com>
Date: Tue, 23 Jan 2024 16:12:25 -0600
From: Andrew Davis <afd@...com>
To: Gerd Hoffmann <kraxel@...hat.com>, Sumit Semwal <sumit.semwal@...aro.org>,
Christian König <christian.koenig@....com>,
Paul Cercueil
<paul@...pouillou.net>
CC: <dri-devel@...ts.freedesktop.org>, <linux-media@...r.kernel.org>,
<linaro-mm-sig@...ts.linaro.org>, <linux-kernel@...r.kernel.org>,
Andrew
Davis <afd@...com>
Subject: [PATCH 1/3] udmabuf: Keep track current device mappings
When a device attaches to and maps our buffer we need to keep track
of this mapping/device. This is needed for synchronization with these
devices when beginning and ending CPU access for instance. Add a list
that tracks device mappings as part of {map,unmap}_udmabuf().
Signed-off-by: Andrew Davis <afd@...com>
---
drivers/dma-buf/udmabuf.c | 43 +++++++++++++++++++++++++++++++++++++--
1 file changed, 41 insertions(+), 2 deletions(-)
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index c406459996489..3a23f0a7d112a 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -28,6 +28,14 @@ struct udmabuf {
struct page **pages;
struct sg_table *sg;
struct miscdevice *device;
+ struct list_head attachments;
+ struct mutex lock;
+};
+
+struct udmabuf_attachment {
+ struct device *dev;
+ struct sg_table *table;
+ struct list_head list;
};
static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf)
@@ -120,14 +128,42 @@ static void put_sg_table(struct device *dev, struct sg_table *sg,
static struct sg_table *map_udmabuf(struct dma_buf_attachment *at,
enum dma_data_direction direction)
{
- return get_sg_table(at->dev, at->dmabuf, direction);
+ struct udmabuf *ubuf = at->dmabuf->priv;
+ struct udmabuf_attachment *a;
+
+ a = kzalloc(sizeof(*a), GFP_KERNEL);
+ if (!a)
+ return ERR_PTR(-ENOMEM);
+
+ a->table = get_sg_table(at->dev, at->dmabuf, direction);
+ if (IS_ERR(a->table)) {
+ kfree(a);
+ return a->table;
+ }
+
+ a->dev = at->dev;
+
+ mutex_lock(&ubuf->lock);
+ list_add(&a->list, &ubuf->attachments);
+ mutex_unlock(&ubuf->lock);
+
+ return a->table;
}
static void unmap_udmabuf(struct dma_buf_attachment *at,
struct sg_table *sg,
enum dma_data_direction direction)
{
- return put_sg_table(at->dev, sg, direction);
+ struct udmabuf_attachment *a = at->priv;
+ struct udmabuf *ubuf = at->dmabuf->priv;
+
+ mutex_lock(&ubuf->lock);
+ list_del(&a->list);
+ mutex_unlock(&ubuf->lock);
+
+ put_sg_table(at->dev, sg, direction);
+
+ kfree(a);
}
static void release_udmabuf(struct dma_buf *buf)
@@ -263,6 +299,9 @@ static long udmabuf_create(struct miscdevice *device,
memfd = NULL;
}
+ INIT_LIST_HEAD(&ubuf->attachments);
+ mutex_init(&ubuf->lock);
+
exp_info.ops = &udmabuf_ops;
exp_info.size = ubuf->pagecount << PAGE_SHIFT;
exp_info.priv = ubuf;
--
2.39.2
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