diff mbox series

[v4,12/14] swiotlb: Add restricted DMA alloc/free support.

Message ID 20210209062131.2300005-13-tientzu@chromium.org (mailing list archive)
State New, archived
Headers show
Series Restricted DMA | expand

Commit Message

Claire Chang Feb. 9, 2021, 6:21 a.m. UTC 
Add the functions, dev_swiotlb_{alloc,free} to support the memory
allocation from restricted DMA pool.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 include/linux/swiotlb.h |  2 ++
 kernel/dma/direct.c     | 30 ++++++++++++++++++++++--------
 kernel/dma/swiotlb.c    | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 8 deletions(-)

Comments

Claire Chang Feb. 26, 2021, 4:17 a.m. UTC | #1 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index fd9c1bd183ac..8b77fd64199e 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -836,6 +836,40 @@ late_initcall(swiotlb_create_default_debugfs);
>  #endif
>
>  #ifdef CONFIG_DMA_RESTRICTED_POOL
> +struct page *dev_swiotlb_alloc(struct device *dev, size_t size, gfp_t gfp)
> +{
> +       struct swiotlb *swiotlb;
> +       phys_addr_t tlb_addr;
> +       unsigned int index;
> +
> +       /* dev_swiotlb_alloc can be used only in the context which permits sleeping. */
> +       if (!dev->dev_swiotlb || !gfpflags_allow_blocking(gfp))

Just noticed that !gfpflags_allow_blocking(gfp) shouldn't be here.

Hi Christoph,

Do you think I should fix this and rebase on the latest linux-next
now? I wonder if there are more factor and clean up coming and I
should wait after that.

Thanks,
Claire
Christoph Hellwig Feb. 26, 2021, 5:17 a.m. UTC | #2 
On Fri, Feb 26, 2021 at 12:17:50PM +0800, Claire Chang wrote:
> Do you think I should fix this and rebase on the latest linux-next
> now? I wonder if there are more factor and clean up coming and I
> should wait after that.

Here is my preferred plan:

 1) wait for my series to support the min alignment in swiotlb to
    land in Linus tree
 2) I'll resend my series with the further swiotlb cleanup and
    refactoring, which includes a slightly rebased version of your
    patch to add the io_tlb_mem structure
 3) resend your series on top of that as a baseline

This is my current WIP tree for 2:

  http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/swiotlb-struct
Claire Chang Feb. 26, 2021, 9:35 a.m. UTC | #3 
On Fri, Feb 26, 2021 at 1:17 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Fri, Feb 26, 2021 at 12:17:50PM +0800, Claire Chang wrote:
> > Do you think I should fix this and rebase on the latest linux-next
> > now? I wonder if there are more factor and clean up coming and I
> > should wait after that.
>
> Here is my preferred plan:
>
>  1) wait for my series to support the min alignment in swiotlb to
>     land in Linus tree
>  2) I'll resend my series with the further swiotlb cleanup and
>     refactoring, which includes a slightly rebased version of your
>     patch to add the io_tlb_mem structure
>  3) resend your series on top of that as a baseline
>
> This is my current WIP tree for 2:
>
>   http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/swiotlb-struct

Sounds good to me. Thanks!
diff mbox series

Patch

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index b9f2a250c8da..2cd39e102915 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -74,6 +74,8 @@  extern enum swiotlb_force swiotlb_force;
 #ifdef CONFIG_DMA_RESTRICTED_POOL
 bool is_swiotlb_force(struct device *dev);
 bool is_dev_swiotlb_force(struct device *dev);
+struct page *dev_swiotlb_alloc(struct device *dev, size_t size, gfp_t gfp);
+bool dev_swiotlb_free(struct device *dev, struct page *page, size_t size);
 #else
 static inline bool is_swiotlb_force(struct device *dev)
 {
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index a76a1a2f24da..f9a9321f7559 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -12,6 +12,7 @@ 
 #include <linux/pfn.h>
 #include <linux/vmalloc.h>
 #include <linux/set_memory.h>
+#include <linux/swiotlb.h>
 #include <linux/slab.h>
 #include "direct.h"
 
@@ -77,6 +78,10 @@  static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 
 static void __dma_direct_free_pages(struct device *dev, struct page *page, size_t size)
 {
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (dev_swiotlb_free(dev, page, size))
+		return;
+#endif
 	dma_free_contiguous(dev, page, size);
 }
 
@@ -89,6 +94,12 @@  static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 
 	WARN_ON_ONCE(!PAGE_ALIGNED(size));
 
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	page = dev_swiotlb_alloc(dev, size, gfp);
+	if (page)
+		return page;
+#endif
+
 	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
 					   &phys_limit);
 	page = dma_alloc_contiguous(dev, size, gfp);
@@ -147,7 +158,7 @@  void *dma_direct_alloc(struct device *dev, size_t size,
 		gfp |= __GFP_NOWARN;
 
 	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev)) {
+	    !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) {
 		page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
 		if (!page)
 			return NULL;
@@ -160,8 +171,8 @@  void *dma_direct_alloc(struct device *dev, size_t size,
 	}
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-	    !dev_is_dma_coherent(dev))
+	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) &&
+	    !is_dev_swiotlb_force(dev))
 		return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
 
 	/*
@@ -171,7 +182,9 @@  void *dma_direct_alloc(struct device *dev, size_t size,
 	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 	    !gfpflags_allow_blocking(gfp) &&
 	    (force_dma_unencrypted(dev) ||
-	     (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev))))
+	     (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+	      !dev_is_dma_coherent(dev))) &&
+	    !is_dev_swiotlb_force(dev))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	/* we always manually zero the memory once we are done */
@@ -252,15 +265,15 @@  void dma_direct_free(struct device *dev, size_t size,
 	unsigned int page_order = get_order(size);
 
 	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev)) {
+	    !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) {
 		/* cpu_addr is a struct page cookie, not a kernel address */
 		dma_free_contiguous(dev, cpu_addr, size);
 		return;
 	}
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-	    !dev_is_dma_coherent(dev)) {
+	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) &&
+	    !is_dev_swiotlb_force(dev)) {
 		arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
 		return;
 	}
@@ -288,7 +301,8 @@  struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	void *ret;
 
 	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
-	    force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp))
+	    force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp) &&
+	    !is_dev_swiotlb_force(dev))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	page = __dma_direct_alloc_pages(dev, size, gfp);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index fd9c1bd183ac..8b77fd64199e 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -836,6 +836,40 @@  late_initcall(swiotlb_create_default_debugfs);
 #endif
 
 #ifdef CONFIG_DMA_RESTRICTED_POOL
+struct page *dev_swiotlb_alloc(struct device *dev, size_t size, gfp_t gfp)
+{
+	struct swiotlb *swiotlb;
+	phys_addr_t tlb_addr;
+	unsigned int index;
+
+	/* dev_swiotlb_alloc can be used only in the context which permits sleeping. */
+	if (!dev->dev_swiotlb || !gfpflags_allow_blocking(gfp))
+		return NULL;
+
+	swiotlb = dev->dev_swiotlb;
+	index = swiotlb_tbl_find_free_region(dev, swiotlb->start, size, 0);
+	if (index < 0)
+		return NULL;
+
+	tlb_addr = swiotlb->start + (index << IO_TLB_SHIFT);
+
+	return pfn_to_page(PFN_DOWN(tlb_addr));
+}
+
+bool dev_swiotlb_free(struct device *dev, struct page *page, size_t size)
+{
+	unsigned int index;
+	phys_addr_t tlb_addr = page_to_phys(page);
+
+	if (!is_swiotlb_buffer(dev, tlb_addr))
+		return false;
+
+	index = (tlb_addr - dev->dev_swiotlb->start) >> IO_TLB_SHIFT;
+	swiotlb_tbl_release_region(dev, index, size);
+
+	return true;
+}
+
 bool is_swiotlb_force(struct device *dev)
 {
 	return unlikely(swiotlb_force == SWIOTLB_FORCE) || dev->dev_swiotlb;