Re: [PATCH 02/13] x86: remove dma_alloc_coherent_mask

[Konrad Rzeszutek Wilk]

On Mon, Mar 05, 2018 at 09:46:44AM -0800, Christoph Hellwig wrote:
> These days all devices (including the ISA fallback device) have a coherent
> DMA mask set, so remove the workaround.
> 
> Signed-off-by: Christoph Hellwig 
Reviewed-by: Konrad Rzeszutek Wilk 

Thank you!
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[PATCH 02/13] x86: remove dma_alloc_coherent_mask

[Christoph Hellwig]

These days all devices (including the ISA fallback device) have a coherent
DMA mask set, so remove the workaround.

Signed-off-by: Christoph Hellwig 
---
 arch/x86/include/asm/dma-mapping.h | 18 ++
 arch/x86/kernel/pci-dma.c  | 10 --
 arch/x86/mm/mem_encrypt.c  |  4 +---
 drivers/xen/swiotlb-xen.c  | 16 +---
 4 files changed, 8 insertions(+), 40 deletions(-)

diff --git a/arch/x86/include/asm/dma-mapping.h 
b/arch/x86/include/asm/dma-mapping.h
index 6277c83c0eb1..545bf3721bc0 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -44,26 +44,12 @@ extern void dma_generic_free_coherent(struct device *dev, 
size_t size,
  void *vaddr, dma_addr_t dma_addr,
  unsigned long attrs);
 
-static inline unsigned long dma_alloc_coherent_mask(struct device *dev,
-   gfp_t gfp)
-{
-   unsigned long dma_mask = 0;
-
-   dma_mask = dev->coherent_dma_mask;
-   if (!dma_mask)
-   dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : 
DMA_BIT_MASK(32);
-
-   return dma_mask;
-}
-
 static inline gfp_t dma_alloc_coherent_gfp_flags(struct device *dev, gfp_t gfp)
 {
-   unsigned long dma_mask = dma_alloc_coherent_mask(dev, gfp);
-
-   if (dma_mask <= DMA_BIT_MASK(24))
+   if (dev->coherent_dma_mask <= DMA_BIT_MASK(24))
gfp |= GFP_DMA;
 #ifdef CONFIG_X86_64
-   if (dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA))
+   if (dev->coherent_dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA))
gfp |= GFP_DMA32;
 #endif
return gfp;
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index df7ab02f959f..b59820872ec7 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -80,13 +80,10 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t 
size,
 dma_addr_t *dma_addr, gfp_t flag,
 unsigned long attrs)
 {
-   unsigned long dma_mask;
struct page *page;
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
dma_addr_t addr;
 
-   dma_mask = dma_alloc_coherent_mask(dev, flag);
-
 again:
page = NULL;
/* CMA can be used only in the context which permits sleeping */
@@ -95,7 +92,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t 
size,
 flag);
if (page) {
addr = phys_to_dma(dev, page_to_phys(page));
-   if (addr + size > dma_mask) {
+   if (addr + size > dev->coherent_dma_mask) {
dma_release_from_contiguous(dev, page, count);
page = NULL;
}
@@ -108,10 +105,11 @@ void *dma_generic_alloc_coherent(struct device *dev, 
size_t size,
return NULL;
 
addr = phys_to_dma(dev, page_to_phys(page));
-   if (addr + size > dma_mask) {
+   if (addr + size > dev->coherent_dma_mask) {
__free_pages(page, get_order(size));
 
-   if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
+   if (dev->coherent_dma_mask < DMA_BIT_MASK(32) &&
+   !(flag & GFP_DMA)) {
flag = (flag & ~GFP_DMA32) | GFP_DMA;
goto again;
}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 1a53071e2e17..75dc8b525c12 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -203,12 +203,10 @@ void __init sme_early_init(void)
 static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
   gfp_t gfp, unsigned long attrs)
 {
-   unsigned long dma_mask;
unsigned int order;
struct page *page;
void *vaddr = NULL;
 
-   dma_mask = dma_alloc_coherent_mask(dev, gfp);
order = get_order(size);
 
/*
@@ -226,7 +224,7 @@ static void *sev_alloc(struct device *dev, size_t size, 
dma_addr_t *dma_handle,
 * mask with it already cleared.
 */
addr = __sme_clr(phys_to_dma(dev, page_to_phys(page)));
-   if ((addr + size) > dma_mask) {
+   if ((addr + size) > dev->coherent_dma_mask) {
__free_pages(page, get_order(size));
} else {
vaddr = page_address(page);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 5bb72d3f8337..e1c60899fdbc 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -53,20 +53,6 @@
  * API.
  */
 
-#ifndef CONFIG_X86
-static unsigned long dma_alloc_coherent_mask(struct device *dev,
-   gfp_t gfp)
-{
-   unsigned long dma_mask =