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[v8,05/15] swiotlb: Add a new get_io_tlb_mem getter

Message ID 20210527125845.1852284-6-tientzu@chromium.org (mailing list archive)
State Superseded
Headers show
Series Restricted DMA | expand

Commit Message

Claire Chang May 27, 2021, 12:58 p.m. UTC 
Add a new getter, get_io_tlb_mem, to help select the io_tlb_mem struct.
The restricted DMA pool is preferred if available.

The reason it was done this way instead of assigning the active pool to
dev->dma_io_tlb_mem was because directly using dev->dma_io_tlb_mem might
cause memory allocation issues for existing devices. The pool can't
support atomic coherent allocation so swiotlb_alloc needs to distinguish
it from the default swiotlb pool.

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

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;