Re: [PATCH RFC 1/5] dma/direct: turn ARCH_ZONE_DMA_BITS into a variable

2019-10-31 Thread Nicolas Saenz Julienne 
On Thu, 2019-10-31 at 06:38 -0700, Christoph Hellwig wrote:
> On Thu, Oct 31, 2019 at 11:30:36AM +0100, Nicolas Saenz Julienne wrote:
> > On Wed, 2019-10-30 at 14:49 -0700, Christoph Hellwig wrote:
> > > On Mon, Oct 14, 2019 at 08:31:03PM +0200, Nicolas Saenz Julienne wrote:
> > > > Some architectures, notably ARM, are interested in tweaking this
> > > > depending on their runtime DMA addressing limitations.
> > > > 
> > > > Signed-off-by: Nicolas Saenz Julienne 
> > > 
> > > Do you want me to pick this up for the 5.5 dma-mapping tree, or do you
> > > want me to wait for the rest to settle?
> > 
> > I'd say take it, this will be ultimately needed once we push forward with
> > ARM.
> 
> Can you resend a version that applies against 5.4-rc?  The current one
> has conflicts in the arm64 code.

Hi Catalin,
would you mind taking this patch on top of the arm64 ZONE_DMA series?

I tried to go though Christoph's tree but it ultimately clashes with the
ZONE_DMA series. It's simpler to apply it on top of your tree.

Regrads,
Nicolas



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Re: [PATCH RFC 1/5] dma/direct: turn ARCH_ZONE_DMA_BITS into a variable

2019-10-31 Thread Christoph Hellwig 
On Thu, Oct 31, 2019 at 11:30:36AM +0100, Nicolas Saenz Julienne wrote:
> On Wed, 2019-10-30 at 14:49 -0700, Christoph Hellwig wrote:
> > On Mon, Oct 14, 2019 at 08:31:03PM +0200, Nicolas Saenz Julienne wrote:
> > > Some architectures, notably ARM, are interested in tweaking this
> > > depending on their runtime DMA addressing limitations.
> > > 
> > > Signed-off-by: Nicolas Saenz Julienne 
> > 
> > Do you want me to pick this up for the 5.5 dma-mapping tree, or do you
> > want me to wait for the rest to settle?
> 
> I'd say take it, this will be ultimately needed once we push forward with ARM.

Can you resend a version that applies against 5.4-rc?  The current one
has conflicts in the arm64 code.

Re: [PATCH RFC 1/5] dma/direct: turn ARCH_ZONE_DMA_BITS into a variable

2019-10-31 Thread Nicolas Saenz Julienne 
On Wed, 2019-10-30 at 14:49 -0700, Christoph Hellwig wrote:
> On Mon, Oct 14, 2019 at 08:31:03PM +0200, Nicolas Saenz Julienne wrote:
> > Some architectures, notably ARM, are interested in tweaking this
> > depending on their runtime DMA addressing limitations.
> > 
> > Signed-off-by: Nicolas Saenz Julienne 
> 
> Do you want me to pick this up for the 5.5 dma-mapping tree, or do you
> want me to wait for the rest to settle?

I'd say take it, this will be ultimately needed once we push forward with ARM.



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Re: [PATCH RFC 1/5] dma/direct: turn ARCH_ZONE_DMA_BITS into a variable

2019-10-30 Thread Christoph Hellwig 
On Mon, Oct 14, 2019 at 08:31:03PM +0200, Nicolas Saenz Julienne wrote:
> Some architectures, notably ARM, are interested in tweaking this
> depending on their runtime DMA addressing limitations.
> 
> Signed-off-by: Nicolas Saenz Julienne 

Do you want me to pick this up for the 5.5 dma-mapping tree, or do you
want me to wait for the rest to settle?

[PATCH RFC 1/5] dma/direct: turn ARCH_ZONE_DMA_BITS into a variable

2019-10-14 Thread Nicolas Saenz Julienne 
Some architectures, notably ARM, are interested in tweaking this
depending on their runtime DMA addressing limitations.

Signed-off-by: Nicolas Saenz Julienne 
---
 arch/arm64/include/asm/page.h   |  2 --
 arch/arm64/mm/init.c|  9 +++--
 arch/powerpc/include/asm/page.h |  9 -
 arch/powerpc/mm/mem.c   | 20 +++-
 arch/s390/include/asm/page.h|  2 --
 arch/s390/mm/init.c |  1 +
 include/linux/dma-direct.h  |  2 ++
 kernel/dma/direct.c | 13 ++---
 8 files changed, 31 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 7b8c98830101..d39ddb258a04 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -38,6 +38,4 @@ extern int pfn_valid(unsigned long);
 
 #include 
 
-#define ARCH_ZONE_DMA_BITS 30
-
 #endif
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 44f07fdf7a59..ddd6a6ce158e 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -20,6 +20,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -41,6 +42,8 @@
 #include 
 #include 
 
+#define ARM64_ZONE_DMA_BITS30
+
 /*
  * We need to be able to catch inadvertent references to memstart_addr
  * that occur (potentially in generic code) before arm64_memblock_init()
@@ -440,8 +443,10 @@ void __init arm64_memblock_init(void)
 
early_init_fdt_scan_reserved_mem();
 
-   if (IS_ENABLED(CONFIG_ZONE_DMA))
-   arm64_dma_phys_limit = max_zone_phys(ARCH_ZONE_DMA_BITS);
+   if (IS_ENABLED(CONFIG_ZONE_DMA)) {
+   zone_dma_bits = ARM64_ZONE_DMA_BITS;
+   arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS);
+   }
 
if (IS_ENABLED(CONFIG_ZONE_DMA32))
arm64_dma32_phys_limit = max_zone_phys(32);
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index c8bb14ff4713..f6c562acc3f8 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -329,13 +329,4 @@ struct vm_area_struct;
 #endif /* __ASSEMBLY__ */
 #include 
 
-/*
- * Allow 30-bit DMA for very limited Broadcom wifi chips on many powerbooks.
- */
-#ifdef CONFIG_PPC32
-#define ARCH_ZONE_DMA_BITS 30
-#else
-#define ARCH_ZONE_DMA_BITS 31
-#endif
-
 #endif /* _ASM_POWERPC_PAGE_H */
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 97e5922cb52e..8bab4e8b6bae 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -31,6 +31,7 @@
 #include 
 #include 
 #include 
+#include 
 
 #include 
 #include 
@@ -200,10 +201,10 @@ static int __init mark_nonram_nosave(void)
  * everything else. GFP_DMA32 page allocations automatically fall back to
  * ZONE_DMA.
  *
- * By using 31-bit unconditionally, we can exploit ARCH_ZONE_DMA_BITS to
- * inform the generic DMA mapping code.  32-bit only devices (if not handled
- * by an IOMMU anyway) will take a first dip into ZONE_NORMAL and get
- * otherwise served by ZONE_DMA.
+ * By using 31-bit unconditionally, we can exploit zone_dma_bits to inform the
+ * generic DMA mapping code.  32-bit only devices (if not handled by an IOMMU
+ * anyway) will take a first dip into ZONE_NORMAL and get otherwise served by
+ * ZONE_DMA.
  */
 static unsigned long max_zone_pfns[MAX_NR_ZONES];
 
@@ -236,9 +237,18 @@ void __init paging_init(void)
printk(KERN_DEBUG "Memory hole size: %ldMB\n",
   (long int)((top_of_ram - total_ram) >> 20));
 
+   /*
+* Allow 30-bit DMA for very limited Broadcom wifi chips on many
+* powerbooks.
+*/
+   if (IS_ENABLED(CONFIG_PPC32))
+   zone_dma_bits = 30;
+   else
+   zone_dma_bits = 31;
+
 #ifdef CONFIG_ZONE_DMA
max_zone_pfns[ZONE_DMA] = min(max_low_pfn,
- 1UL << (ARCH_ZONE_DMA_BITS - PAGE_SHIFT));
+ 1UL << (zone_dma_bits - PAGE_SHIFT));
 #endif
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 #ifdef CONFIG_HIGHMEM
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 823578c6b9e2..a4d38092530a 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -177,8 +177,6 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #define VM_DATA_DEFAULT_FLAGS  (VM_READ | VM_WRITE | \
 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
 
-#define ARCH_ZONE_DMA_BITS 31
-
 #include 
 #include 
 
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index c1d96e588152..ac44bd76db4b 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -118,6 +118,7 @@ void __init paging_init(void)
 
sparse_memory_present_with_active_regions(MAX_NUMNODES);
sparse_init();
+   zone_dma_bits = 31;
memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
diff