dma-debug: don't enforce dma mapping check on noncoherent allocations

As discussed in [1], there is no need to enforce dma mapping check on
noncoherent allocations, a simple test on the returned CPU address is
good enough.

Add a new pair of debug helpers and use them for noncoherent alloc/free
to fix this issue.

Fixes: efa70f2fdc84 ("dma-mapping: add a new dma_alloc_pages API")
Link: https://lore.kernel.org/all/ff6c1fe6-820f-4e58-8395-df06aa91706c@oss.qualcomm.com
Signed-off-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250828-dma-debug-fix-noncoherent-dma-check-v1-1-76e9be0dd7fc@oss.qualcomm.com

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index e43c6de2bce4e7d3e58f8d9601a7637d8f6da767..b82399437db03116a396c7d1cebd16b2e1af98c3 100644 (file)
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -39,6 +39,7 @@ enum {
        dma_debug_sg,
        dma_debug_coherent,
        dma_debug_resource,
+       dma_debug_noncoherent,
 };
 
 enum map_err_types {
@@ -141,6 +142,7 @@ static const char *type2name[] = {
        [dma_debug_sg] = "scatter-gather",
        [dma_debug_coherent] = "coherent",
        [dma_debug_resource] = "resource",
+       [dma_debug_noncoherent] = "noncoherent",
 };
 
 static const char *dir2name[] = {
@@ -993,7 +995,8 @@ static void check_unmap(struct dma_debug_entry *ref)
                           "[mapped as %s] [unmapped as %s]\n",
                           ref->dev_addr, ref->size,
                           type2name[entry->type], type2name[ref->type]);
-       } else if (entry->type == dma_debug_coherent &&
+       } else if ((entry->type == dma_debug_coherent ||
+                   entry->type == dma_debug_noncoherent) &&
                   ref->paddr != entry->paddr) {
                err_printk(ref->dev, entry, "device driver frees "
                           "DMA memory with different CPU address "
@@ -1581,6 +1584,49 @@ void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
        }
 }
 
+void debug_dma_alloc_pages(struct device *dev, struct page *page,
+                          size_t size, int direction,
+                          dma_addr_t dma_addr,
+                          unsigned long attrs)
+{
+       struct dma_debug_entry *entry;
+
+       if (unlikely(dma_debug_disabled()))
+               return;
+
+       entry = dma_entry_alloc();
+       if (!entry)
+               return;
+
+       entry->type      = dma_debug_noncoherent;
+       entry->dev       = dev;
+       entry->paddr     = page_to_phys(page);
+       entry->size      = size;
+       entry->dev_addr  = dma_addr;
+       entry->direction = direction;
+
+       add_dma_entry(entry, attrs);
+}
+
+void debug_dma_free_pages(struct device *dev, struct page *page,
+                         size_t size, int direction,
+                         dma_addr_t dma_addr)
+{
+       struct dma_debug_entry ref = {
+               .type           = dma_debug_noncoherent,
+               .dev            = dev,
+               .paddr          = page_to_phys(page),
+               .dev_addr       = dma_addr,
+               .size           = size,
+               .direction      = direction,
+       };
+
+       if (unlikely(dma_debug_disabled()))
+               return;
+
+       check_unmap(&ref);
+}
+
 static int __init dma_debug_driver_setup(char *str)
 {
        int i;

diff --git a/kernel/dma/debug.h b/kernel/dma/debug.h
index f525197d3cae605aa7e0499eb2ca6f1ae134ec93..48757ca13f31403f58090e1015de828893b8f94f 100644 (file)
--- a/kernel/dma/debug.h
+++ b/kernel/dma/debug.h
@@ -54,6 +54,13 @@ extern void debug_dma_sync_sg_for_cpu(struct device *dev,
 extern void debug_dma_sync_sg_for_device(struct device *dev,
                                         struct scatterlist *sg,
                                         int nelems, int direction);
+extern void debug_dma_alloc_pages(struct device *dev, struct page *page,
+                                 size_t size, int direction,
+                                 dma_addr_t dma_addr,
+                                 unsigned long attrs);
+extern void debug_dma_free_pages(struct device *dev, struct page *page,
+                                size_t size, int direction,
+                                dma_addr_t dma_addr);
 #else /* CONFIG_DMA_API_DEBUG */
 static inline void debug_dma_map_page(struct device *dev, struct page *page,
                                      size_t offset, size_t size,
@@ -126,5 +133,18 @@ static inline void debug_dma_sync_sg_for_device(struct device *dev,
                                                int nelems, int direction)
 {
 }
+
+static inline void debug_dma_alloc_pages(struct device *dev, struct page *page,
+                                        size_t size, int direction,
+                                        dma_addr_t dma_addr,
+                                        unsigned long attrs)
+{
+}
+
+static inline void debug_dma_free_pages(struct device *dev, struct page *page,
+                                       size_t size, int direction,
+                                       dma_addr_t dma_addr)
+{
+}
 #endif /* CONFIG_DMA_API_DEBUG */
 #endif /* _KERNEL_DMA_DEBUG_H */

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 107e4a4d251df65fb86a1d7302261c31138061b7..56de28a3b1799f7c18f7e3f8e5ecd438c5748677 100644 (file)
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -712,7 +712,7 @@ struct page *dma_alloc_pages(struct device *dev, size_t size,
        if (page) {
                trace_dma_alloc_pages(dev, page_to_virt(page), *dma_handle,
                                      size, dir, gfp, 0);
-               debug_dma_map_page(dev, page, 0, size, dir, *dma_handle, 0);
+               debug_dma_alloc_pages(dev, page, size, dir, *dma_handle, 0);
        } else {
                trace_dma_alloc_pages(dev, NULL, 0, size, dir, gfp, 0);
        }
@@ -738,7 +738,7 @@ void dma_free_pages(struct device *dev, size_t size, struct page *page,
                dma_addr_t dma_handle, enum dma_data_direction dir)
 {
        trace_dma_free_pages(dev, page_to_virt(page), dma_handle, size, dir, 0);
-       debug_dma_unmap_page(dev, dma_handle, size, dir);
+       debug_dma_free_pages(dev, page, size, dir, dma_handle);
        __dma_free_pages(dev, size, page, dma_handle, dir);
 }
 EXPORT_SYMBOL_GPL(dma_free_pages);