diff mbox series

[08/13] swiotlb-xen: always use dma-direct helpers to alloc coherent pages

Message ID 20190902130339.23163-9-hch@lst.de (mailing list archive)
State Superseded
Headers show
Series [01/13] xen/arm: use dma-noncoherent.h calls for xen-swiotlb cache maintainance | expand

Commit Message

Christoph Hellwig Sept. 2, 2019, 1:03 p.m. UTC 
x86 currently calls alloc_pages, but using dma-direct works as well
there, with the added benefit of using the CMA pool if available.
The biggest advantage is of course to remove a pointless bit of
architecture specific code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
 arch/x86/include/asm/xen/page-coherent.h | 16 ----------------
 drivers/xen/swiotlb-xen.c                |  7 +++----
 include/xen/arm/page-coherent.h          | 12 ------------
 3 files changed, 3 insertions(+), 32 deletions(-)

Comments

Boris Ostrovsky Sept. 3, 2019, 10:15 p.m. UTC | #1 
On 9/2/19 9:03 AM, Christoph Hellwig wrote:
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index b8808677ae1d..f9dd4cb6e4b3 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -299,8 +299,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
>  	 * address. In fact on ARM virt_to_phys only works for kernel direct
>  	 * mapped RAM memory. Also see comment below.
>  	 */
> -	ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
> -
> +	ret = dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);


If I am reading __dma_direct_alloc_pages() correctly there is a path
that will force us to use GFP_DMA32 and as Juergen pointed out in
another message that may not be desirable.

-boris
Boris Ostrovsky Sept. 3, 2019, 10:25 p.m. UTC | #2 
(Now with correct address for Juergen)

On 9/3/19 6:15 PM, Boris Ostrovsky wrote:
> On 9/2/19 9:03 AM, Christoph Hellwig wrote:
>> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
>> index b8808677ae1d..f9dd4cb6e4b3 100644
>> --- a/drivers/xen/swiotlb-xen.c
>> +++ b/drivers/xen/swiotlb-xen.c
>> @@ -299,8 +299,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
>>  	 * address. In fact on ARM virt_to_phys only works for kernel direct
>>  	 * mapped RAM memory. Also see comment below.
>>  	 */
>> -	ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
>> -
>> +	ret = dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
>
> If I am reading __dma_direct_alloc_pages() correctly there is a path
> that will force us to use GFP_DMA32 and as Juergen pointed out in
> another message that may not be desirable.
>
> -boris
>
>
>
Christoph Hellwig Sept. 4, 2019, 7 a.m. UTC | #3 
On Tue, Sep 03, 2019 at 06:25:54PM -0400, Boris Ostrovsky wrote:
> > If I am reading __dma_direct_alloc_pages() correctly there is a path
> > that will force us to use GFP_DMA32 and as Juergen pointed out in
> > another message that may not be desirable.

Yes, it will add GFP_DMA32.  So I guess for now we'll just keep the
direct page allocator calls and resend.  I don't think this is the
right thing to do long term, but I'd really like to get this series
finished.
diff mbox series

Patch

diff --git a/arch/x86/include/asm/xen/page-coherent.h b/arch/x86/include/asm/xen/page-coherent.h
index 116777e7f387..8ee33c5edded 100644
--- a/arch/x86/include/asm/xen/page-coherent.h
+++ b/arch/x86/include/asm/xen/page-coherent.h
@@ -5,22 +5,6 @@ 
 #include <asm/page.h>
 #include <linux/dma-mapping.h>
 
-static inline void *xen_alloc_coherent_pages(struct device *hwdev, size_t size,
-		dma_addr_t *dma_handle, gfp_t flags,
-		unsigned long attrs)
-{
-	void *vstart = (void*)__get_free_pages(flags, get_order(size));
-	*dma_handle = virt_to_phys(vstart);
-	return vstart;
-}
-
-static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
-		void *cpu_addr, dma_addr_t dma_handle,
-		unsigned long attrs)
-{
-	free_pages((unsigned long) cpu_addr, get_order(size));
-}
-
 static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
 	     dma_addr_t dev_addr, unsigned long offset, size_t size,
 	     enum dma_data_direction dir, unsigned long attrs) { }
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index b8808677ae1d..f9dd4cb6e4b3 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -299,8 +299,7 @@  xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 	 * address. In fact on ARM virt_to_phys only works for kernel direct
 	 * mapped RAM memory. Also see comment below.
 	 */
-	ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
-
+	ret = dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
 	if (!ret)
 		return ret;
 
@@ -319,7 +318,7 @@  xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 	else {
 		if (xen_create_contiguous_region(phys, order,
 						 fls64(dma_mask), dma_handle) != 0) {
-			xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
+			dma_direct_free(hwdev, size, ret, (dma_addr_t)phys, attrs);
 			return NULL;
 		}
 		SetPageXenRemapped(virt_to_page(ret));
@@ -351,7 +350,7 @@  xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
 	    TestClearPageXenRemapped(virt_to_page(vaddr)))
 		xen_destroy_contiguous_region(phys, order);
 
-	xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
+	dma_direct_free(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
 }
 
 /*
diff --git a/include/xen/arm/page-coherent.h b/include/xen/arm/page-coherent.h
index a840d6949a87..0e244f4fec1a 100644
--- a/include/xen/arm/page-coherent.h
+++ b/include/xen/arm/page-coherent.h
@@ -16,18 +16,6 @@  void __xen_dma_sync_single_for_cpu(struct device *hwdev,
 void __xen_dma_sync_single_for_device(struct device *hwdev,
 		dma_addr_t handle, size_t size, enum dma_data_direction dir);
 
-static inline void *xen_alloc_coherent_pages(struct device *hwdev, size_t size,
-		dma_addr_t *dma_handle, gfp_t flags, unsigned long attrs)
-{
-	return dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
-}
-
-static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
-		void *cpu_addr, dma_addr_t dma_handle, unsigned long attrs)
-{
-	dma_direct_free(hwdev, size, cpu_addr, dma_handle, attrs);
-}
-
 static inline void xen_dma_sync_single_for_cpu(struct device *hwdev,
 		dma_addr_t handle, size_t size, enum dma_data_direction dir)
 {