Add a new getter, get_io_tlb_mem, to help select the io_tlb_mem struct.
The restricted DMA pool is preferred if available.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/swiotlb.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 03ad6e3b4056..b469f04cca26 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -2,6 +2,7 @@
 #ifndef __LINUX_SWIOTLB_H
 #define __LINUX_SWIOTLB_H
 
+#include <linux/device.h>
 #include <linux/dma-direction.h>
 #include <linux/init.h>
 #include <linux/types.h>
@@ -102,6 +103,16 @@ struct io_tlb_mem {
 };
 extern struct io_tlb_mem *io_tlb_default_mem;
 
+static inline struct io_tlb_mem *get_io_tlb_mem(struct device *dev)
+{
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (dev && dev->dma_io_tlb_mem)
+		return dev->dma_io_tlb_mem;
+#endif /* CONFIG_DMA_RESTRICTED_POOL */
+
+	return io_tlb_default_mem;
+}
+
 static inline bool is_swiotlb_buffer(phys_addr_t paddr)
 {
 	struct io_tlb_mem *mem = io_tlb_default_mem;
-- 
2.31.1.751.gd2f1c929bd-goog

Still keep this function because directly using dev->dma_io_tlb_mem
will cause issues for memory allocation for existing devices. The pool
can't support atomic coherent allocation so we need to distinguish the
per device pool and the default pool in swiotlb_alloc.

On Tue, May 18, 2021 at 02:51:52PM +0800, Claire Chang wrote:
> Still keep this function because directly using dev->dma_io_tlb_mem
> will cause issues for memory allocation for existing devices. The pool
> can't support atomic coherent allocation so we need to distinguish the
> per device pool and the default pool in swiotlb_alloc.

This above should really be rolled in the commit. You can prefix it by
"The reason it was done this way was because directly using .."

On Mon, May 24, 2021 at 11:51 PM Konrad Rzeszutek Wilk
<konrad.wilk@oracle.com> wrote:
>
> On Tue, May 18, 2021 at 02:51:52PM +0800, Claire Chang wrote:
> > Still keep this function because directly using dev->dma_io_tlb_mem
> > will cause issues for memory allocation for existing devices. The pool
> > can't support atomic coherent allocation so we need to distinguish the
> > per device pool and the default pool in swiotlb_alloc.
>
> This above should really be rolled in the commit. You can prefix it by
> "The reason it was done this way was because directly using .."
>

Will add it.

On 5/17/2021 11:42 PM, Claire Chang wrote:
> Add a new getter, get_io_tlb_mem, to help select the io_tlb_mem struct.
> The restricted DMA pool is preferred if available.
> 
> Signed-off-by: Claire Chang <tientzu@chromium.org>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian