dma-mapping fixes for Linux 6.0

- revert a panic on swiotlb initialization failure (Yu Zhao)
  - fix the lookup for partial syncs in dma-debug (Robin Murphy)
  - fix a shift overflow in swiotlb (Chao Gao)
  - fix a comment typo in swiotlb (Chao Gao)
  - mark a function static now that all abusers are gone
    (Christoph Hellwig)
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Merge tag 'dma-mapping-6.0-2022-09-10' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:

 - revert a panic on swiotlb initialization failure (Yu Zhao)

 - fix the lookup for partial syncs in dma-debug (Robin Murphy)

 - fix a shift overflow in swiotlb (Chao Gao)

 - fix a comment typo in swiotlb (Chao Gao)

 - mark a function static now that all abusers are gone (Christoph
   Hellwig)

* tag 'dma-mapping-6.0-2022-09-10' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: mark dma_supported static
  swiotlb: fix a typo
  swiotlb: avoid potential left shift overflow
  dma-debug: improve search for partial syncs
  Revert "swiotlb: panic if nslabs is too small"

include/linux/dma-mapping.h

@@ -139,7 +139,6 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 		void *cpu_addr, dma_addr_t dma_addr, size_t size,
 		unsigned long attrs);
 bool dma_can_mmap(struct device *dev);
-int dma_supported(struct device *dev, u64 mask);
 bool dma_pci_p2pdma_supported(struct device *dev);
 int dma_set_mask(struct device *dev, u64 mask);
 int dma_set_coherent_mask(struct device *dev, u64 mask);
@@ -248,10 +247,6 @@ static inline bool dma_can_mmap(struct device *dev)
 {
 	return false;
 }
-static inline int dma_supported(struct device *dev, u64 mask)
-{
-	return 0;
-}
 static inline bool dma_pci_p2pdma_supported(struct device *dev)
 {
 	return false;

kernel/dma/debug.c

@@ -350,11 +350,10 @@ static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 						   unsigned long *flags)
 {
 
-	unsigned int max_range = dma_get_max_seg_size(ref->dev);
 	struct dma_debug_entry *entry, index = *ref;
-	unsigned int range = 0;
+	int limit = min(HASH_SIZE, (index.dev_addr >> HASH_FN_SHIFT) + 1);
 
-	while (range <= max_range) {
+	for (int i = 0; i < limit; i++) {
 		entry = __hash_bucket_find(*bucket, ref, containing_match);
 
 		if (entry)
@@ -364,7 +363,6 @@ static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 		 * Nothing found, go back a hash bucket
 		 */
 		put_hash_bucket(*bucket, *flags);
-		range          += (1 << HASH_FN_SHIFT);
 		index.dev_addr -= (1 << HASH_FN_SHIFT);
 		*bucket = get_hash_bucket(&index, flags);
 	}

kernel/dma/mapping.c

@@ -707,7 +707,7 @@ int dma_mmap_noncontiguous(struct device *dev, struct vm_area_struct *vma,
 }
 EXPORT_SYMBOL_GPL(dma_mmap_noncontiguous);
 
-int dma_supported(struct device *dev, u64 mask)
+static int dma_supported(struct device *dev, u64 mask)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
 
@@ -721,7 +721,6 @@ int dma_supported(struct device *dev, u64 mask)
 		return 1;
 	return ops->dma_supported(dev, mask);
 }
-EXPORT_SYMBOL(dma_supported);
 
 bool dma_pci_p2pdma_supported(struct device *dev)
 {

kernel/dma/swiotlb.c

@@ -326,9 +326,6 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
 		swiotlb_adjust_nareas(num_possible_cpus());
 
 	nslabs = default_nslabs;
-	if (nslabs < IO_TLB_MIN_SLABS)
-		panic("%s: nslabs = %lu too small\n", __func__, nslabs);
-
 	/*
 	 * By default allocate the bounce buffer memory from low memory, but
 	 * allow to pick a location everywhere for hypervisors with guest
@@ -341,8 +338,7 @@ retry:
 	else
 		tlb = memblock_alloc_low(bytes, PAGE_SIZE);
 	if (!tlb) {
-		pr_warn("%s: Failed to allocate %zu bytes tlb structure\n",
-			__func__, bytes);
+		pr_warn("%s: failed to allocate tlb structure\n", __func__);
 		return;
 	}
 
@@ -579,7 +575,10 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
 	}
 }
 
-#define slot_addr(start, idx)	((start) + ((idx) << IO_TLB_SHIFT))
+static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx)
+{
+	return start + (idx << IO_TLB_SHIFT);
+}
 
 /*
  * Carefully handle integer overflow which can occur when boundary_mask == ~0UL.
@@ -765,7 +764,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
 	/*
 	 * When dir == DMA_FROM_DEVICE we could omit the copy from the orig
 	 * to the tlb buffer, if we knew for sure the device will
-	 * overwirte the entire current content. But we don't. Thus
+	 * overwrite the entire current content. But we don't. Thus
 	 * unconditional bounce may prevent leaking swiotlb content (i.e.
 	 * kernel memory) to user-space.
 	 */