Re: [PATCH v4 03/16] dma-debug: refactor to use physical addresses for page mapping
From: Jason Gunthorpe <jgg@nvidia.com>
Date: 2025-08-28 13:19:58
Also in:
linux-block, linux-doc, linux-iommu, linux-mm, linux-nvme, linux-trace-kernel, lkml, rust-for-linux, virtualization, xen-devel
Subsystem:
dma mapping helpers, the rest · Maintainers:
Marek Szyprowski, Linus Torvalds
On Tue, Aug 19, 2025 at 08:36:47PM +0300, Leon Romanovsky wrote:
quoted hunk ↗ jump to hunk
@@ -1218,19 +1219,24 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset, return; entry->dev = dev; - entry->type = dma_debug_single; - entry->paddr = page_to_phys(page) + offset; + entry->type = dma_debug_phy; + entry->paddr = phys; entry->dev_addr = dma_addr; entry->size = size; entry->direction = direction; entry->map_err_type = MAP_ERR_NOT_CHECKED; - check_for_stack(dev, page, offset); + if (!(attrs & DMA_ATTR_MMIO)) { + struct page *page = phys_to_page(phys); + size_t offset = offset_in_page(page); - if (!PageHighMem(page)) { - void *addr = page_address(page) + offset; + check_for_stack(dev, page, offset); - check_for_illegal_area(dev, addr, size); + if (!PageHighMem(page)) { + void *addr = page_address(page) + offset; + + check_for_illegal_area(dev, addr, size); + } }
Not anything to change in this series, but I was looking at what it would take to someday remove the struct page here and it looks reasonable.
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 06e31fd216e38e..0d6dd3eb9860ac 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c@@ -1051,28 +1051,28 @@ static void check_unmap(struct dma_debug_entry *ref) dma_entry_free(entry); } -static void check_for_stack(struct device *dev, - struct page *page, size_t offset) +static void check_for_stack(struct device *dev, phys_addr_t phys) { void *addr; struct vm_struct *stack_vm_area = task_stack_vm_area(current); if (!stack_vm_area) { /* Stack is direct-mapped. */ - if (PageHighMem(page)) + if (PhysHighMem(phys)) return; - addr = page_address(page) + offset; + addr = phys_to_virt(phys); if (object_is_on_stack(addr)) err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr); } else { /* Stack is vmalloced. */ + unsigned long pfn = phys >> PAGE_SHIFT; int i; for (i = 0; i < stack_vm_area->nr_pages; i++) { - if (page != stack_vm_area->pages[i]) + if (pfn != page_to_pfn(stack_vm_area->pages[i])) continue; - addr = (u8 *)current->stack + i * PAGE_SIZE + offset; + addr = (u8 *)current->stack + i * PAGE_SIZE + (phys % PAGE_SIZE); err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr); break; }
@@ -1225,16 +1225,10 @@ void debug_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size, entry->map_err_type = MAP_ERR_NOT_CHECKED; if (!(attrs & DMA_ATTR_MMIO)) { - struct page *page = phys_to_page(phys); - size_t offset = offset_in_page(page); + check_for_stack(dev, phys); - check_for_stack(dev, page, offset); - - if (!PageHighMem(page)) { - void *addr = page_address(page) + offset; - - check_for_illegal_area(dev, addr, size); - } + if (!PhysHighMem(phys)) + check_for_illegal_area(dev, phys_to_virt(phys), size); } add_dma_entry(entry, attrs);