2022-06-09 01:03:50

by Dongli Zhang

Subject: [PATCH RFC v1 5/7] swiotlb: add interface to set dev->dma_io_tlb_mem

The interface re-configures dev->dma_io_tlb_mem conditionally, if the
'io_tlb_high_mem' is active.

Cc: Konrad Wilk <[email protected]>
Cc: Joe Jin <[email protected]>
Signed-off-by: Dongli Zhang <[email protected]>
---
include/linux/swiotlb.h | 6 ++++++
kernel/dma/swiotlb.c | 10 ++++++++++
2 files changed, 16 insertions(+)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 8196bf961aab..78217d8bbee2 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -131,6 +131,7 @@ unsigned int swiotlb_max_segment(void);
size_t swiotlb_max_mapping_size(struct device *dev);
bool is_swiotlb_active(struct device *dev);
void __init swiotlb_adjust_size(unsigned long size);
+bool swiotlb_use_high(struct device *dev);
#else
static inline void swiotlb_init(bool addressing_limited, unsigned int flags)
{
@@ -163,6 +164,11 @@ static inline bool is_swiotlb_active(struct device *dev)
static inline void swiotlb_adjust_size(unsigned long size)
{
}
+
+static bool swiotlb_use_high(struct device *dev);
+{
+ return false;
+}
#endif /* CONFIG_SWIOTLB */

extern bool swiotlb_high_active(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index ff82b281ce01..0dcdd25ea95d 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -121,6 +121,16 @@ bool swiotlb_high_active(void)
return high_nslabs && io_tlb_high_mem.nslabs;
}

+bool swiotlb_use_high(struct device *dev)
+{
+ if (!swiotlb_high_active())
+ return false;
+
+ dev->dma_io_tlb_mem = &io_tlb_high_mem;
+ return true;
+}
+EXPORT_SYMBOL_GPL(swiotlb_use_high);
+
unsigned int swiotlb_max_segment(void)
{
if (!io_tlb_default_mem.nslabs)
--
2.17.1

2022-06-09 05:16:07

by Christoph Hellwig

Subject: Re: [PATCH RFC v1 5/7] swiotlb: add interface to set dev->dma_io_tlb_mem

This should be handled under the hood without the driver even knowing.