diff mbox series

[v6,2/9] swiotlb: make io_tlb_default_mem local to swiotlb.c

Message ID e97d4eca870c3eb2ca86e173e22c0d0b14485bbf.1690459412.git.petr.tesarik.ext@huawei.com (mailing list archive)
State Superseded
Headers show
Series Allow dynamic allocation of software IO TLB bounce buffers | expand

Commit Message

Petr Tesarik July 27, 2023, 12:05 p.m. UTC 
From: Petr Tesarik <petr.tesarik.ext@huawei.com>

SWIOTLB implementation details should not be exposed to the rest of the
kernel. This will allow to make changes to the implementation without
modifying non-swiotlb code.

To avoid breaking existing users, provide helper functions for the few
required fields.

As a bonus, using a helper function to initialize struct device allows to
get rid of an #ifdef in driver core.

Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
---
 arch/mips/pci/pci-octeon.c |  2 +-
 drivers/base/core.c        |  4 +---
 drivers/xen/swiotlb-xen.c  |  2 +-
 include/linux/swiotlb.h    | 25 +++++++++++++++++++++++-
 kernel/dma/swiotlb.c       | 39 +++++++++++++++++++++++++++++++++++++-
 mm/slab_common.c           |  5 ++---
 6 files changed, 67 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/arch/mips/pci/pci-octeon.c b/arch/mips/pci/pci-octeon.c
index e457a18cbdc5..d19d9d456309 100644
--- a/arch/mips/pci/pci-octeon.c
+++ b/arch/mips/pci/pci-octeon.c
@@ -664,7 +664,7 @@  static int __init octeon_pci_setup(void)
 
 		/* BAR1 movable regions contiguous to cover the swiotlb */
 		octeon_bar1_pci_phys =
-			io_tlb_default_mem.start & ~((1ull << 22) - 1);
+			default_swiotlb_base() & ~((1ull << 22) - 1);
 
 		for (index = 0; index < 32; index++) {
 			union cvmx_pci_bar1_indexx bar1_index;
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 3dff5037943e..46d1d78c5beb 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3108,9 +3108,7 @@  void device_initialize(struct device *dev)
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
 	dev->dma_coherent = dma_default_coherent;
 #endif
-#ifdef CONFIG_SWIOTLB
-	dev->dma_io_tlb_mem = &io_tlb_default_mem;
-#endif
+	swiotlb_dev_init(dev);
 }
 EXPORT_SYMBOL_GPL(device_initialize);
 
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 67aa74d20162..946bd56f0ac5 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -381,7 +381,7 @@  xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
 static int
 xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
-	return xen_phys_to_dma(hwdev, io_tlb_default_mem.end - 1) <= mask;
+	return xen_phys_to_dma(hwdev, default_swiotlb_limit()) <= mask;
 }
 
 const struct dma_map_ops xen_swiotlb_dma_ops = {
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 4e52cd5e0bdc..2d453b3e7771 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -110,7 +110,6 @@  struct io_tlb_mem {
 	atomic_long_t used_hiwater;
 #endif
 };
-extern struct io_tlb_mem io_tlb_default_mem;
 
 static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
@@ -128,13 +127,22 @@  static inline bool is_swiotlb_force_bounce(struct device *dev)
 
 void swiotlb_init(bool addressing_limited, unsigned int flags);
 void __init swiotlb_exit(void);
+void swiotlb_dev_init(struct device *dev);
 size_t swiotlb_max_mapping_size(struct device *dev);
+bool is_swiotlb_allocated(void);
 bool is_swiotlb_active(struct device *dev);
 void __init swiotlb_adjust_size(unsigned long size);
+phys_addr_t default_swiotlb_base(void);
+phys_addr_t default_swiotlb_limit(void);
 #else
 static inline void swiotlb_init(bool addressing_limited, unsigned int flags)
 {
 }
+
+static inline void swiotlb_dev_init(struct device *dev)
+{
+}
+
 static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
 	return false;
@@ -151,6 +159,11 @@  static inline size_t swiotlb_max_mapping_size(struct device *dev)
 	return SIZE_MAX;
 }
 
+static inline bool is_swiotlb_allocated(void)
+{
+	return false;
+}
+
 static inline bool is_swiotlb_active(struct device *dev)
 {
 	return false;
@@ -159,6 +172,16 @@  static inline bool is_swiotlb_active(struct device *dev)
 static inline void swiotlb_adjust_size(unsigned long size)
 {
 }
+
+static inline phys_addr_t default_swiotlb_base(void)
+{
+	return 0;
+}
+
+static inline phys_addr_t default_swiotlb_limit(void)
+{
+	return 0;
+}
 #endif /* CONFIG_SWIOTLB */
 
 extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 66fc8ec9ae45..0b173303e088 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -71,7 +71,7 @@  struct io_tlb_slot {
 static bool swiotlb_force_bounce;
 static bool swiotlb_force_disable;
 
-struct io_tlb_mem io_tlb_default_mem;
+static struct io_tlb_mem io_tlb_default_mem;
 
 static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT;
 static unsigned long default_nareas;
@@ -489,6 +489,15 @@  void __init swiotlb_exit(void)
 	memset(mem, 0, sizeof(*mem));
 }
 
+/**
+ * swiotlb_dev_init() - initialize swiotlb fields in &struct device
+ * @dev:	Device to be initialized.
+ */
+void swiotlb_dev_init(struct device *dev)
+{
+	dev->dma_io_tlb_mem = &io_tlb_default_mem;
+}
+
 /*
  * Return the offset into a iotlb slot required to keep the device happy.
  */
@@ -953,6 +962,14 @@  size_t swiotlb_max_mapping_size(struct device *dev)
 	return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align;
 }
 
+/**
+ * is_swiotlb_allocated() - check if the default software IO TLB is initialized
+ */
+bool is_swiotlb_allocated(void)
+{
+	return io_tlb_default_mem.nslabs;
+}
+
 bool is_swiotlb_active(struct device *dev)
 {
 	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
@@ -961,6 +978,26 @@  bool is_swiotlb_active(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(is_swiotlb_active);
 
+/**
+ * default_swiotlb_base() - get the base address of the default SWIOTLB
+ *
+ * Get the lowest physical address used by the default software IO TLB pool.
+ */
+phys_addr_t default_swiotlb_base(void)
+{
+	return io_tlb_default_mem.start;
+}
+
+/**
+ * default_swiotlb_limit() - get the address limit of the default SWIOTLB
+ *
+ * Get the highest physical address used by the default software IO TLB pool.
+ */
+phys_addr_t default_swiotlb_limit(void)
+{
+	return io_tlb_default_mem.end - 1;
+}
+
 #ifdef CONFIG_DEBUG_FS
 
 static int io_tlb_used_get(void *data, u64 *val)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index d1555ea2981a..c639dba9a3b7 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -864,10 +864,9 @@  void __init setup_kmalloc_cache_index_table(void)
 
 static unsigned int __kmalloc_minalign(void)
 {
-#ifdef CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC
-	if (io_tlb_default_mem.nslabs)
+	if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) &&
+	    is_swiotlb_allocated())
 		return ARCH_KMALLOC_MINALIGN;
-#endif
 	return dma_get_cache_alignment();
 }