Merge tag 'dma-mapping-6.1-2022-10-10' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - fix a regression in the ARM dma-direct conversion (Christoph Hellwig)

 - use memcpy_{from,to}_page (Fabio M. De Francesco)

 - cleanup the swiotlb MAINTAINERS entry (Lukas Bulwahn)

 - make SG table pool allocation less fragile (Masahiro Yamada)

 - don't panic on swiotlb initialization failure (Robin Murphy)

* tag 'dma-mapping-6.1-2022-10-10' of git://git.infradead.org/users/hch/dma-mapping:
  ARM/dma-mapping: remove the dma_coherent member of struct dev_archdata
  ARM/dma-mappіng: don't override ->dma_coherent when set from a bus notifier
  lib/sg_pool: change module_init(sg_pool_init) to subsys_initcall
  MAINTAINERS: merge SWIOTLB SUBSYSTEM into DMA MAPPING HELPERS
  swiotlb: don't panic!
  swiotlb: replace kmap_atomic() with memcpy_{from,to}_page()

1 files changed, 23 insertions, 17 deletions

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 0ef6b12f961d..339a990554e7 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -346,22 +346,27 @@ retry:
 		memblock_free(tlb, PAGE_ALIGN(bytes));
 
 		nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
-		if (nslabs < IO_TLB_MIN_SLABS)
-			panic("%s: Failed to remap %zu bytes\n",
-			      __func__, bytes);
-		goto retry;
+		if (nslabs >= IO_TLB_MIN_SLABS)
+			goto retry;
+
+		pr_warn("%s: Failed to remap %zu bytes\n", __func__, bytes);
+		return;
 	}
 
 	alloc_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), nslabs));
 	mem->slots = memblock_alloc(alloc_size, PAGE_SIZE);
-	if (!mem->slots)
-		panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
-		      __func__, alloc_size, PAGE_SIZE);
+	if (!mem->slots) {
+		pr_warn("%s: Failed to allocate %zu bytes align=0x%lx\n",
+			__func__, alloc_size, PAGE_SIZE);
+		return;
+	}
 
 	mem->areas = memblock_alloc(array_size(sizeof(struct io_tlb_area),
 		default_nareas), SMP_CACHE_BYTES);
-	if (!mem->areas)
-		panic("%s: Failed to allocate mem->areas.\n", __func__);
+	if (!mem->areas) {
+		pr_warn("%s: Failed to allocate mem->areas.\n", __func__);
+		return;
+	}
 
 	swiotlb_init_io_tlb_mem(mem, __pa(tlb), nslabs, flags, false,
 				default_nareas);
@@ -545,9 +550,8 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
 	}
 
 	if (PageHighMem(pfn_to_page(pfn))) {
-		/* The buffer does not have a mapping.  Map it in and copy */
 		unsigned int offset = orig_addr & ~PAGE_MASK;
-		char *buffer;
+		struct page *page;
 		unsigned int sz = 0;
 		unsigned long flags;
 
@@ -555,12 +559,11 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
 			sz = min_t(size_t, PAGE_SIZE - offset, size);
 
 			local_irq_save(flags);
-			buffer = kmap_atomic(pfn_to_page(pfn));
+			page = pfn_to_page(pfn);
 			if (dir == DMA_TO_DEVICE)
-				memcpy(vaddr, buffer + offset, sz);
+				memcpy_from_page(vaddr, page, offset, sz);
 			else
-				memcpy(buffer + offset, vaddr, sz);
-			kunmap_atomic(buffer);
+				memcpy_to_page(page, offset, vaddr, sz);
 			local_irq_restore(flags);
 
 			size -= sz;
@@ -731,8 +734,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
 	int index;
 	phys_addr_t tlb_addr;
 
-	if (!mem || !mem->nslabs)
-		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
+	if (!mem || !mem->nslabs) {
+		dev_warn_ratelimited(dev,
+			"Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+	}
 
 	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");