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 <[email protected]> --- drivers/dma-buf/udmabuf.c | 45 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 43 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 40399c26e6be6..cc5c1cc42c7f2 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -42,6 +42,14 @@ struct udmabuf { struct sg_table *sg; struct miscdevice *device; pgoff_t *offsets; + struct list_head attachments; + struct mutex lock; /* for attachments list */ +}; + +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) @@ -185,14 +193,44 @@ 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; + struct sg_table *table; + + a = kzalloc(sizeof(*a), GFP_KERNEL); + if (!a) + return ERR_PTR(-ENOMEM); + + table = get_sg_table(at->dev, at->dmabuf, direction); + if (IS_ERR(table)) { + kfree(a); + return table; + } + + a->dev = at->dev; + a->table = table; + + 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 unpin_all_folios(struct udmabuf *ubuf) @@ -384,6 +422,9 @@ static long udmabuf_create(struct miscdevice *device, if (!ubuf) return -ENOMEM; + INIT_LIST_HEAD(&ubuf->attachments); + mutex_init(&ubuf->lock); + pglimit = ((u64)size_limit_mb * 1024 * 1024) >> PAGE_SHIFT; for (i = 0; i < head->count; i++) { pgoff_t subpgcnt; -- 2.39.2
