From: Petr Tesarik <[email protected]>
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 <[email protected]>
---
arch/arm/xen/mm.c | 2 +-
arch/mips/pci/pci-octeon.c | 2 +-
arch/x86/kernel/pci-dma.c | 2 +-
drivers/base/core.c | 4 +---
drivers/xen/swiotlb-xen.c | 2 +-
include/linux/swiotlb.h | 25 +++++++++++++++++++++++-
kernel/dma/swiotlb.c | 39 +++++++++++++++++++++++++++++++++++++-
7 files changed, 67 insertions(+), 9 deletions(-)
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 3d826c0b5fee..0f32c14eb786 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -125,7 +125,7 @@ static int __init xen_mm_init(void)
return 0;
/* we can work with the default swiotlb */
- if (!io_tlb_default_mem.nslabs) {
+ if (!is_swiotlb_allocated()) {
rc = swiotlb_init_late(swiotlb_size_or_default(),
xen_swiotlb_gfp(), NULL);
if (rc < 0)
diff --git a/arch/mips/pci/pci-octeon.c b/arch/mips/pci/pci-octeon.c
index e457a18cbdc5..c5c4c1f7d5e4 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_start() & ~((1ull << 22) - 1);
for (index = 0; index < 32; index++) {
union cvmx_pci_bar1_indexx bar1_index;
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index de6be0a3965e..08c6ffc3550f 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -90,7 +90,7 @@ int pci_xen_swiotlb_init_late(void)
return 0;
/* we can work with the default swiotlb */
- if (!io_tlb_default_mem.nslabs) {
+ if (!is_swiotlb_allocated()) {
int rc = swiotlb_init_late(swiotlb_size_or_default(),
GFP_KERNEL, xen_swiotlb_fixup);
if (rc < 0)
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..07216af59e93 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_start(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_start(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 2b83e3ad9dca..873b077d7e37 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;
@@ -486,6 +486,15 @@ 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.
*/
@@ -950,6 +959,14 @@ 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;
@@ -958,6 +975,26 @@ bool is_swiotlb_active(struct device *dev)
}
EXPORT_SYMBOL_GPL(is_swiotlb_active);
+/**
+ * default_swiotlb_start() - get the start of the default SWIOTLB
+ *
+ * Get the lowest physical address used by the default software IO TLB pool.
+ */
+phys_addr_t default_swiotlb_start(void)
+{
+ return io_tlb_default_mem.start;
+}
+
+/**
+ * default_swiotlb_limit() - get the highest address in 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)
--
2.25.1
Hi Petr,
On 13/7/23 17:23, Petr Tesarik wrote:
> From: Petr Tesarik <[email protected]>
>
> 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 <[email protected]>
> ---
> arch/arm/xen/mm.c | 2 +-
> arch/mips/pci/pci-octeon.c | 2 +-
> arch/x86/kernel/pci-dma.c | 2 +-
> drivers/base/core.c | 4 +---
> drivers/xen/swiotlb-xen.c | 2 +-
> include/linux/swiotlb.h | 25 +++++++++++++++++++++++-
> kernel/dma/swiotlb.c | 39 +++++++++++++++++++++++++++++++++++++-
> 7 files changed, 67 insertions(+), 9 deletions(-)
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 4e52cd5e0bdc..07216af59e93 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_start(void);
> +phys_addr_t default_swiotlb_limit(void);
Usually we use start/end, base/limit, low[est]/high[est] tuples.
Possibly clearer to rename, regardless:
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 2b83e3ad9dca..873b077d7e37 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -958,6 +975,26 @@ bool is_swiotlb_active(struct device *dev)
> }
> EXPORT_SYMBOL_GPL(is_swiotlb_active);
>
> +/**
> + * default_swiotlb_start() - get the start of the default SWIOTLB
> + *
> + * Get the lowest physical address used by the default software IO TLB pool.
> + */
> +phys_addr_t default_swiotlb_start(void)
> +{
> + return io_tlb_default_mem.start;
> +}
> +
> +/**
> + * default_swiotlb_limit() - get the highest address in the default SWIOTLB
> + *
> + * Get the highest physical address used by the default software IO TLB pool.
(note you describe lowest/highest).
> + */
> +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)
On Mon, 17 Jul 2023 08:06:07 +0200
Philippe Mathieu-Daudé <[email protected]> wrote:
> Hi Petr,
>
> On 13/7/23 17:23, Petr Tesarik wrote:
> > From: Petr Tesarik <[email protected]>
> >
> > 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 <[email protected]>
> > ---
> > arch/arm/xen/mm.c | 2 +-
> > arch/mips/pci/pci-octeon.c | 2 +-
> > arch/x86/kernel/pci-dma.c | 2 +-
> > drivers/base/core.c | 4 +---
> > drivers/xen/swiotlb-xen.c | 2 +-
> > include/linux/swiotlb.h | 25 +++++++++++++++++++++++-
> > kernel/dma/swiotlb.c | 39 +++++++++++++++++++++++++++++++++++++-
> > 7 files changed, 67 insertions(+), 9 deletions(-)
>
>
> > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> > index 4e52cd5e0bdc..07216af59e93 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_start(void);
> > +phys_addr_t default_swiotlb_limit(void);
>
> Usually we use start/end, base/limit, low[est]/high[est] tuples.
I'm no big fan of start/end, because the "end" sometimes means "highest
within range" and sometimes "one past range", being responsible for an
impressive amount of off-by-one errors.
But I agree. When I decided against "end", I should have also replaced
"start" with "base". Well, this patch series will certainly see a v5,
so I'll change it there. Thanks for the suggestion!
Petr T
> Possibly clearer to rename, regardless:
> Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
>
> > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> > index 2b83e3ad9dca..873b077d7e37 100644
> > --- a/kernel/dma/swiotlb.c
> > +++ b/kernel/dma/swiotlb.c
>
>
> > @@ -958,6 +975,26 @@ bool is_swiotlb_active(struct device *dev)
> > }
> > EXPORT_SYMBOL_GPL(is_swiotlb_active);
> >
> > +/**
> > + * default_swiotlb_start() - get the start of the default SWIOTLB
> > + *
> > + * Get the lowest physical address used by the default software IO TLB pool.
> > + */
> > +phys_addr_t default_swiotlb_start(void)
> > +{
> > + return io_tlb_default_mem.start;
> > +}
> > +
> > +/**
> > + * default_swiotlb_limit() - get the highest address in the default SWIOTLB
> > + *
> > + * Get the highest physical address used by the default software IO TLB pool.
>
> (note you describe lowest/highest).
>
> > + */
> > +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)
>
On Thu, 20 Jul 2023 08:37:44 +0200
Christoph Hellwig <[email protected]> wrote:
> On Thu, Jul 13, 2023 at 05:23:12PM +0200, Petr Tesarik wrote:
> > From: Petr Tesarik <[email protected]>
> >
> > 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 <[email protected]>
> > ---
> > arch/arm/xen/mm.c | 2 +-
> > arch/mips/pci/pci-octeon.c | 2 +-
> > arch/x86/kernel/pci-dma.c | 2 +-
> > drivers/base/core.c | 4 +---
> > drivers/xen/swiotlb-xen.c | 2 +-
> > include/linux/swiotlb.h | 25 +++++++++++++++++++++++-
> > kernel/dma/swiotlb.c | 39 +++++++++++++++++++++++++++++++++++++-
> > 7 files changed, 67 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
> > index 3d826c0b5fee..0f32c14eb786 100644
> > --- a/arch/arm/xen/mm.c
> > +++ b/arch/arm/xen/mm.c
> > @@ -125,7 +125,7 @@ static int __init xen_mm_init(void)
> > return 0;
> >
> > /* we can work with the default swiotlb */
> > - if (!io_tlb_default_mem.nslabs) {
> > + if (!is_swiotlb_allocated()) {
> > rc = swiotlb_init_late(swiotlb_size_or_default(),
> > xen_swiotlb_gfp(), NULL);
> > if (rc < 0)
>
> I'd much rather move the already initialized check into
> swiotlb_init_late, which is a much cleaer interface.
>
> > /* we can work with the default swiotlb */
> > - if (!io_tlb_default_mem.nslabs) {
> > + if (!is_swiotlb_allocated()) {
> > int rc = swiotlb_init_late(swiotlb_size_or_default(),
> > GFP_KERNEL, xen_swiotlb_fixup);
> > if (rc < 0)
>
> .. and would take care of this one as well.
Oh, you're right! These are the only two places that look at
io_tlb_default_mem.nslabs, and all they need is to avoid double
initialization. Makes perfect sense to move it inside
swiotlb_init_late().
> > +bool is_swiotlb_allocated(void)
> > +{
> > + return !!io_tlb_default_mem.nslabs;
>
> Nit: no need for the !!, we can rely on the implicit promotion to
> bool. But with the suggestion above the need for this helper
> should go away anyway.
Eh, yes. I initially declared the return type as int and then forgot to
change the return statement. But as you say, the whole function will go
away entirely.
Petr T
On Thu, Jul 13, 2023 at 05:23:12PM +0200, Petr Tesarik wrote:
> From: Petr Tesarik <[email protected]>
>
> 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 <[email protected]>
> ---
> arch/arm/xen/mm.c | 2 +-
> arch/mips/pci/pci-octeon.c | 2 +-
> arch/x86/kernel/pci-dma.c | 2 +-
> drivers/base/core.c | 4 +---
> drivers/xen/swiotlb-xen.c | 2 +-
> include/linux/swiotlb.h | 25 +++++++++++++++++++++++-
> kernel/dma/swiotlb.c | 39 +++++++++++++++++++++++++++++++++++++-
> 7 files changed, 67 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
> index 3d826c0b5fee..0f32c14eb786 100644
> --- a/arch/arm/xen/mm.c
> +++ b/arch/arm/xen/mm.c
> @@ -125,7 +125,7 @@ static int __init xen_mm_init(void)
> return 0;
>
> /* we can work with the default swiotlb */
> - if (!io_tlb_default_mem.nslabs) {
> + if (!is_swiotlb_allocated()) {
> rc = swiotlb_init_late(swiotlb_size_or_default(),
> xen_swiotlb_gfp(), NULL);
> if (rc < 0)
I'd much rather move the already initialized check into
swiotlb_init_late, which is a much cleaer interface.
> /* we can work with the default swiotlb */
> - if (!io_tlb_default_mem.nslabs) {
> + if (!is_swiotlb_allocated()) {
> int rc = swiotlb_init_late(swiotlb_size_or_default(),
> GFP_KERNEL, xen_swiotlb_fixup);
> if (rc < 0)
.. and would take care of this one as well.
> +bool is_swiotlb_allocated(void)
> +{
> + return !!io_tlb_default_mem.nslabs;
Nit: no need for the !!, we can rely on the implicit promotion to
bool. But with the suggestion above the need for this helper
should go away anyway.