[PATCH v15 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing

From: Claire Chang
Date: Thu Jun 24 2021 - 11:56:36 EST


Propagate the swiotlb_force into io_tlb_default_mem->force_bounce and
use it to determine whether to bounce the data or not. This will be
useful later to allow for different pools.

Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Tested-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Tested-by: Will Deacon <will@xxxxxxxxxx>
Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
drivers/xen/swiotlb-xen.c | 2 +-
include/linux/swiotlb.h | 13 +++++++++++++
kernel/dma/direct.c | 2 +-
kernel/dma/direct.h | 2 +-
kernel/dma/swiotlb.c | 4 ++++
5 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 0c6ed09f8513..4730a146fa35 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -369,7 +369,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
if (dma_capable(dev, dev_addr, size, true) &&
!range_straddles_page_boundary(phys, size) &&
!xen_arch_need_swiotlb(dev, phys, dev_addr) &&
- swiotlb_force != SWIOTLB_FORCE)
+ !is_swiotlb_force_bounce(dev))
goto done;

/*
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index dd1c30a83058..da348671b0d5 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -84,6 +84,7 @@ extern enum swiotlb_force swiotlb_force;
* unmap calls.
* @debugfs: The dentry to debugfs.
* @late_alloc: %true if allocated using the page allocator
+ * @force_bounce: %true if swiotlb bouncing is forced
*/
struct io_tlb_mem {
phys_addr_t start;
@@ -94,6 +95,7 @@ struct io_tlb_mem {
spinlock_t lock;
struct dentry *debugfs;
bool late_alloc;
+ bool force_bounce;
struct io_tlb_slot {
phys_addr_t orig_addr;
size_t alloc_size;
@@ -109,6 +111,13 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
return mem && paddr >= mem->start && paddr < mem->end;
}

+static inline bool is_swiotlb_force_bounce(struct device *dev)
+{
+ struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+
+ return mem && mem->force_bounce;
+}
+
void __init swiotlb_exit(void);
unsigned int swiotlb_max_segment(void);
size_t swiotlb_max_mapping_size(struct device *dev);
@@ -120,6 +129,10 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
{
return false;
}
+static inline bool is_swiotlb_force_bounce(struct device *dev)
+{
+ return false;
+}
static inline void swiotlb_exit(void)
{
}
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 7a88c34d0867..a92465b4eb12 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -496,7 +496,7 @@ size_t dma_direct_max_mapping_size(struct device *dev)
{
/* If SWIOTLB is active, use its maximum mapping size */
if (is_swiotlb_active(dev) &&
- (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE))
+ (dma_addressing_limited(dev) || is_swiotlb_force_bounce(dev)))
return swiotlb_max_mapping_size(dev);
return SIZE_MAX;
}
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
index 13e9e7158d94..4632b0f4f72e 100644
--- a/kernel/dma/direct.h
+++ b/kernel/dma/direct.h
@@ -87,7 +87,7 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev,
phys_addr_t phys = page_to_phys(page) + offset;
dma_addr_t dma_addr = phys_to_dma(dev, phys);

- if (unlikely(swiotlb_force == SWIOTLB_FORCE))
+ if (is_swiotlb_force_bounce(dev))
return swiotlb_map(dev, phys, size, dir, attrs);

if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 8a120f42340b..0d294bbf274c 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -179,6 +179,10 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
mem->end = mem->start + bytes;
mem->index = 0;
mem->late_alloc = late_alloc;
+
+ if (swiotlb_force == SWIOTLB_FORCE)
+ mem->force_bounce = true;
+
spin_lock_init(&mem->lock);
for (i = 0; i < mem->nslabs; i++) {
mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i);
--
2.32.0.288.g62a8d224e6-goog