2 files changed, 167 insertions, 67 deletions

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 69da09a085a1..8fcc09c91e1b 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -85,6 +85,7 @@ static u32 show_num_errors = 1;
 
 static u32 num_free_entries;
 static u32 min_free_entries;
+static u32 nr_total_entries;
 
 /* number of preallocated entries requested by kernel cmdline */
 static u32 req_entries;
@@ -185,15 +186,50 @@ static void put_hash_bucket(struct hash_bucket *bucket,
 static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
                                                 struct dma_debug_entry *ref)
 {
-        struct dma_debug_entry *entry;
+        struct dma_debug_entry *entry, *ret = NULL;
+        int matches = 0, match_lvl, last_lvl = 0;
 
         list_for_each_entry(entry, &bucket->list, list) {
-                if ((entry->dev_addr == ref->dev_addr) &&
-                    (entry->dev == ref->dev))
+                if ((entry->dev_addr != ref->dev_addr) ||
+                    (entry->dev != ref->dev))
+                        continue;
+
+                /*
+                 * Some drivers map the same physical address multiple
+                 * times. Without a hardware IOMMU this results in the
+                 * same device addresses being put into the dma-debug
+                 * hash multiple times too. This can result in false
+                 * positives being reported. Therfore we implement a
+                 * best-fit algorithm here which returns the entry from
+                 * the hash which fits best to the reference value
+                 * instead of the first-fit.
+                 */
+                matches += 1;
+                match_lvl = 0;
+                entry->size      == ref->size      ? ++match_lvl : match_lvl;
+                entry->type      == ref->type      ? ++match_lvl : match_lvl;
+                entry->direction == ref->direction ? ++match_lvl : match_lvl;
+
+                if (match_lvl == 3) {
+                        /* perfect-fit - return the result */
                         return entry;
+                } else if (match_lvl > last_lvl) {
+                        /*
+                         * We found an entry that fits better then the
+                         * previous one
+                         */
+                        last_lvl = match_lvl;
+                        ret      = entry;
+                }
         }
 
-        return NULL;
+        /*
+         * If we have multiple matches but no perfect-fit, just return
+         * NULL.
+         */
+        ret = (matches == 1) ? ret : NULL;
+
+        return ret;
 }
 
 /*
@@ -257,6 +293,21 @@ static void add_dma_entry(struct dma_debug_entry *entry)
         put_hash_bucket(bucket, &flags);
 }
 
+static struct dma_debug_entry *__dma_entry_alloc(void)
+{
+        struct dma_debug_entry *entry;
+
+        entry = list_entry(free_entries.next, struct dma_debug_entry, list);
+        list_del(&entry->list);
+        memset(entry, 0, sizeof(*entry));
+
+        num_free_entries -= 1;
+        if (num_free_entries < min_free_entries)
+                min_free_entries = num_free_entries;
+
+        return entry;
+}
+
 /* struct dma_entry allocator
  *
  * The next two functions implement the allocator for
@@ -276,9 +327,7 @@ static struct dma_debug_entry *dma_entry_alloc(void)
                 goto out;
         }
 
-        entry = list_entry(free_entries.next, struct dma_debug_entry, list);
-        list_del(&entry->list);
-        memset(entry, 0, sizeof(*entry));
+        entry = __dma_entry_alloc();
 
 #ifdef CONFIG_STACKTRACE
         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
@@ -286,9 +335,6 @@ static struct dma_debug_entry *dma_entry_alloc(void)
         entry->stacktrace.skip = 2;
         save_stack_trace(&entry->stacktrace);
 #endif
-        num_free_entries -= 1;
-        if (num_free_entries < min_free_entries)
-                min_free_entries = num_free_entries;
 
 out:
         spin_unlock_irqrestore(&free_entries_lock, flags);
@@ -310,6 +356,53 @@ static void dma_entry_free(struct dma_debug_entry *entry)
         spin_unlock_irqrestore(&free_entries_lock, flags);
 }
 
+int dma_debug_resize_entries(u32 num_entries)
+{
+        int i, delta, ret = 0;
+        unsigned long flags;
+        struct dma_debug_entry *entry;
+        LIST_HEAD(tmp);
+
+        spin_lock_irqsave(&free_entries_lock, flags);
+
+        if (nr_total_entries < num_entries) {
+                delta = num_entries - nr_total_entries;
+
+                spin_unlock_irqrestore(&free_entries_lock, flags);
+
+                for (i = 0; i < delta; i++) {
+                        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+                        if (!entry)
+                                break;
+
+                        list_add_tail(&entry->list, &tmp);
+                }
+
+                spin_lock_irqsave(&free_entries_lock, flags);
+
+                list_splice(&tmp, &free_entries);
+                nr_total_entries += i;
+                num_free_entries += i;
+        } else {
+                delta = nr_total_entries - num_entries;
+
+                for (i = 0; i < delta && !list_empty(&free_entries); i++) {
+                        entry = __dma_entry_alloc();
+                        kfree(entry);
+                }
+
+                nr_total_entries -= i;
+        }
+
+        if (nr_total_entries != num_entries)
+                ret = 1;
+
+        spin_unlock_irqrestore(&free_entries_lock, flags);
+
+        return ret;
+}
+EXPORT_SYMBOL(dma_debug_resize_entries);
+
 /*
  * DMA-API debugging init code
  *
@@ -439,6 +532,8 @@ void dma_debug_init(u32 num_entries)
                 return;
         }
 
+        nr_total_entries = num_free_entries;
+
         printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
 }
 
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 2b0b5a7d2ced..bffe6d7ef9d9 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -60,8 +60,8 @@ enum dma_sync_target {
 int swiotlb_force;
 
 /*
- * Used to do a quick range check in swiotlb_unmap_single and
- * swiotlb_sync_single_*, to see if the memory was in fact allocated by this
+ * Used to do a quick range check in unmap_single and
+ * sync_single_*, to see if the memory was in fact allocated by this
  * API.
  */
 static char *io_tlb_start, *io_tlb_end;
@@ -129,7 +129,7 @@ dma_addr_t __weak swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
         return paddr;
 }
 
-phys_addr_t __weak swiotlb_bus_to_phys(dma_addr_t baddr)
+phys_addr_t __weak swiotlb_bus_to_phys(struct device *hwdev, dma_addr_t baddr)
 {
         return baddr;
 }
@@ -140,9 +140,15 @@ static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
         return swiotlb_phys_to_bus(hwdev, virt_to_phys(address));
 }
 
-static void *swiotlb_bus_to_virt(dma_addr_t address)
+void * __weak swiotlb_bus_to_virt(struct device *hwdev, dma_addr_t address)
 {
-        return phys_to_virt(swiotlb_bus_to_phys(address));
+        return phys_to_virt(swiotlb_bus_to_phys(hwdev, address));
+}
+
+int __weak swiotlb_arch_address_needs_mapping(struct device *hwdev,
+                                               dma_addr_t addr, size_t size)
+{
+        return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
 }
 
 int __weak swiotlb_arch_range_needs_mapping(phys_addr_t paddr, size_t size)
@@ -309,10 +315,10 @@ cleanup1:
         return -ENOMEM;
 }
 
-static int
+static inline int
 address_needs_mapping(struct device *hwdev, dma_addr_t addr, size_t size)
 {
-        return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
+        return swiotlb_arch_address_needs_mapping(hwdev, addr, size);
 }
 
 static inline int range_needs_mapping(phys_addr_t paddr, size_t size)
@@ -341,7 +347,7 @@ static void swiotlb_bounce(phys_addr_t phys, char *dma_addr, size_t size,
                 unsigned long flags;
 
                 while (size) {
-                        sz = min(PAGE_SIZE - offset, size);
+                        sz = min_t(size_t, PAGE_SIZE - offset, size);
 
                         local_irq_save(flags);
                         buffer = kmap_atomic(pfn_to_page(pfn),
@@ -476,7 +482,7 @@ found:
  * dma_addr is the kernel virtual address of the bounce buffer to unmap.
  */
 static void
-unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
+do_unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
 {
         unsigned long flags;
         int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
@@ -560,7 +566,6 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                                    size)) {
                 /*
                  * The allocated memory isn't reachable by the device.
-                 * Fall back on swiotlb_map_single().
                  */
                 free_pages((unsigned long) ret, order);
                 ret = NULL;
@@ -568,9 +573,8 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
         if (!ret) {
                 /*
                  * We are either out of memory or the device can't DMA
-                 * to GFP_DMA memory; fall back on
-                 * swiotlb_map_single(), which will grab memory from
-                 * the lowest available address range.
+                 * to GFP_DMA memory; fall back on map_single(), which
+                 * will grab memory from the lowest available address range.
                  */
                 ret = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
                 if (!ret)
@@ -587,7 +591,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                        (unsigned long long)dev_addr);
 
                 /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
-                unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
+                do_unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
                 return NULL;
         }
         *dma_handle = dev_addr;
@@ -604,7 +608,7 @@ swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
                 free_pages((unsigned long) vaddr, get_order(size));
         else
                 /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
-                unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
+                do_unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
 }
 EXPORT_SYMBOL(swiotlb_free_coherent);
 
@@ -634,7 +638,7 @@ swiotlb_full(struct device *dev, size_t size, int dir, int do_panic)
  * physical address to use is returned.
  *
  * Once the device is given the dma address, the device owns this memory until
- * either swiotlb_unmap_single or swiotlb_dma_sync_single is performed.
+ * either swiotlb_unmap_page or swiotlb_dma_sync_single is performed.
  */
 dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
                             unsigned long offset, size_t size,
@@ -642,18 +646,17 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
                             struct dma_attrs *attrs)
 {
         phys_addr_t phys = page_to_phys(page) + offset;
-        void *ptr = page_address(page) + offset;
         dma_addr_t dev_addr = swiotlb_phys_to_bus(dev, phys);
         void *map;
 
         BUG_ON(dir == DMA_NONE);
         /*
-         * If the pointer passed in happens to be in the device's DMA window,
+         * If the address happens to be in the device's DMA window,
          * we can safely return the device addr and not worry about bounce
          * buffering it.
          */
         if (!address_needs_mapping(dev, dev_addr, size) &&
-            !range_needs_mapping(virt_to_phys(ptr), size))
+            !range_needs_mapping(phys, size))
                 return dev_addr;
 
         /*
@@ -679,23 +682,35 @@ EXPORT_SYMBOL_GPL(swiotlb_map_page);
 
 /*
  * Unmap a single streaming mode DMA translation.  The dma_addr and size must
- * match what was provided for in a previous swiotlb_map_single call.  All
+ * match what was provided for in a previous swiotlb_map_page call.  All
  * other usages are undefined.
  *
  * After this call, reads by the cpu to the buffer are guaranteed to see
  * whatever the device wrote there.
  */
+static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
+                         size_t size, int dir)
+{
+        char *dma_addr = swiotlb_bus_to_virt(hwdev, dev_addr);
+
+        BUG_ON(dir == DMA_NONE);
+
+        if (is_swiotlb_buffer(dma_addr)) {
+                do_unmap_single(hwdev, dma_addr, size, dir);
+                return;
+        }
+
+        if (dir != DMA_FROM_DEVICE)
+                return;
+
+        dma_mark_clean(dma_addr, size);
+}
+
 void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
                         size_t size, enum dma_data_direction dir,
                         struct dma_attrs *attrs)
 {
-        char *dma_addr = swiotlb_bus_to_virt(dev_addr);
-
-        BUG_ON(dir == DMA_NONE);
-        if (is_swiotlb_buffer(dma_addr))
-                unmap_single(hwdev, dma_addr, size, dir);
-        else if (dir == DMA_FROM_DEVICE)
-                dma_mark_clean(dma_addr, size);
+        unmap_single(hwdev, dev_addr, size, dir);
 }
 EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
 
@@ -703,7 +718,7 @@ EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
  * Make physical memory consistent for a single streaming mode DMA translation
  * after a transfer.
  *
- * If you perform a swiotlb_map_single() but wish to interrogate the buffer
+ * If you perform a swiotlb_map_page() but wish to interrogate the buffer
  * using the cpu, yet do not wish to teardown the dma mapping, you must
  * call this function before doing so.  At the next point you give the dma
  * address back to the card, you must first perform a
@@ -713,13 +728,19 @@ static void
 swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
                     size_t size, int dir, int target)
 {
-        char *dma_addr = swiotlb_bus_to_virt(dev_addr);
+        char *dma_addr = swiotlb_bus_to_virt(hwdev, dev_addr);
 
         BUG_ON(dir == DMA_NONE);
-        if (is_swiotlb_buffer(dma_addr))
+
+        if (is_swiotlb_buffer(dma_addr)) {
                 sync_single(hwdev, dma_addr, size, dir, target);
-        else if (dir == DMA_FROM_DEVICE)
-                dma_mark_clean(dma_addr, size);
+                return;
+        }
+
+        if (dir != DMA_FROM_DEVICE)
+                return;
+
+        dma_mark_clean(dma_addr, size);
 }
 
 void
@@ -746,13 +767,7 @@ swiotlb_sync_single_range(struct device *hwdev, dma_addr_t dev_addr,
                           unsigned long offset, size_t size,
                           int dir, int target)
 {
-        char *dma_addr = swiotlb_bus_to_virt(dev_addr) + offset;
-
-        BUG_ON(dir == DMA_NONE);
-        if (is_swiotlb_buffer(dma_addr))
-                sync_single(hwdev, dma_addr, size, dir, target);
-        else if (dir == DMA_FROM_DEVICE)
-                dma_mark_clean(dma_addr, size);
+        swiotlb_sync_single(hwdev, dev_addr + offset, size, dir, target);
 }
 
 void
@@ -777,7 +792,7 @@ EXPORT_SYMBOL_GPL(swiotlb_sync_single_range_for_device);
 
 /*
  * Map a set of buffers described by scatterlist in streaming mode for DMA.
- * This is the scatter-gather version of the above swiotlb_map_single
+ * This is the scatter-gather version of the above swiotlb_map_page
  * interface.  Here the scatter gather list elements are each tagged with the
  * appropriate dma address and length.  They are obtained via
  * sg_dma_{address,length}(SG).
@@ -788,7 +803,7 @@ EXPORT_SYMBOL_GPL(swiotlb_sync_single_range_for_device);
  *       The routine returns the number of addr/length pairs actually
  *       used, at most nents.
  *
- * Device ownership issues as mentioned above for swiotlb_map_single are the
+ * Device ownership issues as mentioned above for swiotlb_map_page are the
  * same here.
  */
 int
@@ -836,7 +851,7 @@ EXPORT_SYMBOL(swiotlb_map_sg);
 
 /*
  * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
- * concerning calls here are the same as for swiotlb_unmap_single() above.
+ * concerning calls here are the same as for swiotlb_unmap_page() above.
  */
 void
 swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
@@ -847,13 +862,9 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 
         BUG_ON(dir == DMA_NONE);
 
-        for_each_sg(sgl, sg, nelems, i) {
-                if (sg->dma_address != swiotlb_phys_to_bus(hwdev, sg_phys(sg)))
-                        unmap_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
-                                     sg->dma_length, dir);
-                else if (dir == DMA_FROM_DEVICE)
-                        dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
-        }
+        for_each_sg(sgl, sg, nelems, i)
+                unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
+
 }
 EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
 
@@ -879,15 +890,9 @@ swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
         struct scatterlist *sg;
         int i;
 
-        BUG_ON(dir == DMA_NONE);
-
-        for_each_sg(sgl, sg, nelems, i) {
-                if (sg->dma_address != swiotlb_phys_to_bus(hwdev, sg_phys(sg)))
-                        sync_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
+        for_each_sg(sgl, sg, nelems, i)
+                swiotlb_sync_single(hwdev, sg->dma_address,
                                     sg->dma_length, dir, target);
-                else if (dir == DMA_FROM_DEVICE)
-                        dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
-        }
 }
 
 void