6 files changed, 234 insertions, 77 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index b0f239e443bc..eae594cb6ea9 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -252,6 +252,14 @@ config DEBUG_OBJECTS_TIMERS
           timer routines to track the life time of timer objects and
           validate the timer operations.
 
+config DEBUG_OBJECTS_ENABLE_DEFAULT
+        int "debug_objects bootup default value (0-1)"
+        range 0 1
+        default "1"
+        depends on DEBUG_OBJECTS
+        help
+          Debug objects boot parameter default value
+
 config DEBUG_SLAB
         bool "Debug slab memory allocations"
         depends on DEBUG_KERNEL && SLAB
@@ -545,6 +553,16 @@ config DEBUG_SG
 
           If unsure, say N.
 
+config DEBUG_NOTIFIERS
+        bool "Debug notifier call chains"
+        depends on DEBUG_KERNEL
+        help
+          Enable this to turn on sanity checking for notifier call chains.
+          This is most useful for kernel developers to make sure that
+          modules properly unregister themselves from notifier chains.
+          This is a relatively cheap check but if you care about maximum
+          performance, say N.
+
 config FRAME_POINTER
         bool "Compile the kernel with frame pointers"
         depends on DEBUG_KERNEL && \
@@ -619,6 +637,19 @@ config RCU_CPU_STALL_DETECTOR
 
           Say N if you are unsure.
 
+config RCU_CPU_STALL_DETECTOR
+        bool "Check for stalled CPUs delaying RCU grace periods"
+        depends on CLASSIC_RCU || TREE_RCU
+        default n
+        help
+          This option causes RCU to printk information on which
+          CPUs are delaying the current grace period, but only when
+          the grace period extends for excessive time periods.
+
+          Say Y if you want RCU to perform such checks.
+
+          Say N if you are unsure.
+
 config KPROBES_SANITY_TEST
         bool "Kprobes sanity tests"
         depends on DEBUG_KERNEL
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index e3ab374e1334..5d99be1fd988 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -45,7 +45,9 @@ static struct kmem_cache	*obj_cache;
 static int                      debug_objects_maxchain __read_mostly;
 static int                      debug_objects_fixups __read_mostly;
 static int                      debug_objects_warnings __read_mostly;
-static int                      debug_objects_enabled __read_mostly;
+static int                      debug_objects_enabled __read_mostly
+                                = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
+
 static struct debug_obj_descr   *descr_test  __read_mostly;
 
 static int __init enable_object_debug(char *str)
diff --git a/lib/dynamic_printk.c b/lib/dynamic_printk.c
index d83660fd6fdd..8e30295e8566 100644
--- a/lib/dynamic_printk.c
+++ b/lib/dynamic_printk.c
@@ -135,7 +135,7 @@ int unregister_dynamic_debug_module(char *mod_name)
         nr_entries--;
 out:
         up(&debug_list_mutex);
-        return 0;
+        return ret;
 }
 EXPORT_SYMBOL_GPL(unregister_dynamic_debug_module);
 
@@ -289,7 +289,7 @@ static ssize_t pr_debug_write(struct file *file, const char __user *buf,
                                         dynamic_enabled = DYNAMIC_ENABLED_SOME;
                                         err = 0;
                                         printk(KERN_DEBUG
-                                               "debugging enabled for module %s",
+                                               "debugging enabled for module %s\n",
                                                elem->name);
                                 } else if (!value && (elem->enable == 1)) {
                                         elem->enable = 0;
@@ -309,7 +309,7 @@ static ssize_t pr_debug_write(struct file *file, const char __user *buf,
                                         err = 0;
                                         printk(KERN_DEBUG
                                                "debugging disabled for module "
-                                               "%s", elem->name);
+                                               "%s\n", elem->name);
                                 }
                         }
                 }
diff --git a/lib/idr.c b/lib/idr.c
index 7a785a0c2ea0..1c4f9281f412 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -220,8 +220,14 @@ build_up:
          */
         while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) {
                 layers++;
-                if (!p->count)
+                if (!p->count) {
+                        /* special case: if the tree is currently empty,
+                         * then we grow the tree by moving the top node
+                         * upwards.
+                         */
+                        p->layer++;
                         continue;
+                }
                 if (!(new = get_from_free_list(idp))) {
                         /*
                          * The allocation failed.  If we built part of
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index a8663890a88c..b255b939bc1b 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -62,10 +62,7 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc)
         for_each_online_cpu(cpu) {
                 s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
                 ret += *pcount;
-                *pcount = 0;
         }
-        fbc->count = ret;
-
         spin_unlock(&fbc->lock);
         return ret;
 }
@@ -104,13 +101,13 @@ void percpu_counter_destroy(struct percpu_counter *fbc)
         if (!fbc->counters)
                 return;
 
-        free_percpu(fbc->counters);
-        fbc->counters = NULL;
 #ifdef CONFIG_HOTPLUG_CPU
         mutex_lock(&percpu_counters_lock);
         list_del(&fbc->list);
         mutex_unlock(&percpu_counters_lock);
 #endif
+        free_percpu(fbc->counters);
+        fbc->counters = NULL;
 }
 EXPORT_SYMBOL(percpu_counter_destroy);
 
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 5f6c629a924d..fa2dc4e5f9ba 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -21,9 +21,12 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
+#include <linux/swiotlb.h>
 #include <linux/string.h>
+#include <linux/swiotlb.h>
 #include <linux/types.h>
 #include <linux/ctype.h>
+#include <linux/highmem.h>
 
 #include <asm/io.h>
 #include <asm/dma.h>
@@ -36,22 +39,6 @@
 #define OFFSET(val,align) ((unsigned long)      \
                            ( (val) & ( (align) - 1)))
 
-#define SG_ENT_VIRT_ADDRESS(sg) (sg_virt((sg)))
-#define SG_ENT_PHYS_ADDRESS(sg) virt_to_bus(SG_ENT_VIRT_ADDRESS(sg))
-
-/*
- * Maximum allowable number of contiguous slabs to map,
- * must be a power of 2.  What is the appropriate value ?
- * The complexity of {map,unmap}_single is linearly dependent on this value.
- */
-#define IO_TLB_SEGSIZE  128
-
-/*
- * log of the size of each IO TLB slab.  The number of slabs is command line
- * controllable.
- */
-#define IO_TLB_SHIFT 11
-
 #define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
 
 /*
@@ -102,7 +89,10 @@ static unsigned int io_tlb_index;
  * We need to save away the original address corresponding to a mapped entry
  * for the sync operations.
  */
-static unsigned char **io_tlb_orig_addr;
+static struct swiotlb_phys_addr {
+        struct page *page;
+        unsigned int offset;
+} *io_tlb_orig_addr;
 
 /*
  * Protect the above data structures in the map and unmap calls
@@ -126,6 +116,72 @@ setup_io_tlb_npages(char *str)
 __setup("swiotlb=", setup_io_tlb_npages);
 /* make io_tlb_overflow tunable too? */
 
+void * __weak swiotlb_alloc_boot(size_t size, unsigned long nslabs)
+{
+        return alloc_bootmem_low_pages(size);
+}
+
+void * __weak swiotlb_alloc(unsigned order, unsigned long nslabs)
+{
+        return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
+}
+
+dma_addr_t __weak swiotlb_phys_to_bus(phys_addr_t paddr)
+{
+        return paddr;
+}
+
+phys_addr_t __weak swiotlb_bus_to_phys(dma_addr_t baddr)
+{
+        return baddr;
+}
+
+static dma_addr_t swiotlb_virt_to_bus(volatile void *address)
+{
+        return swiotlb_phys_to_bus(virt_to_phys(address));
+}
+
+static void *swiotlb_bus_to_virt(dma_addr_t address)
+{
+        return phys_to_virt(swiotlb_bus_to_phys(address));
+}
+
+int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
+{
+        return 0;
+}
+
+static dma_addr_t swiotlb_sg_to_bus(struct scatterlist *sg)
+{
+        return swiotlb_phys_to_bus(page_to_phys(sg_page(sg)) + sg->offset);
+}
+
+static void swiotlb_print_info(unsigned long bytes)
+{
+        phys_addr_t pstart, pend;
+        dma_addr_t bstart, bend;
+
+        pstart = virt_to_phys(io_tlb_start);
+        pend = virt_to_phys(io_tlb_end);
+
+        bstart = swiotlb_phys_to_bus(pstart);
+        bend = swiotlb_phys_to_bus(pend);
+
+        printk(KERN_INFO "Placing %luMB software IO TLB between %p - %p\n",
+               bytes >> 20, io_tlb_start, io_tlb_end);
+        if (pstart != bstart || pend != bend)
+                printk(KERN_INFO "software IO TLB at phys %#llx - %#llx"
+                       " bus %#llx - %#llx\n",
+                       (unsigned long long)pstart,
+                       (unsigned long long)pend,
+                       (unsigned long long)bstart,
+                       (unsigned long long)bend);
+        else
+                printk(KERN_INFO "software IO TLB at phys %#llx - %#llx\n",
+                       (unsigned long long)pstart,
+                       (unsigned long long)pend);
+}
+
 /*
  * Statically reserve bounce buffer space and initialize bounce buffer data
  * structures for the software IO TLB used to implement the DMA API.
@@ -145,7 +201,7 @@ swiotlb_init_with_default_size(size_t default_size)
         /*
          * Get IO TLB memory from the low pages
          */
-        io_tlb_start = alloc_bootmem_low_pages(bytes);
+        io_tlb_start = swiotlb_alloc_boot(bytes, io_tlb_nslabs);
         if (!io_tlb_start)
                 panic("Cannot allocate SWIOTLB buffer");
         io_tlb_end = io_tlb_start + bytes;
@@ -159,7 +215,7 @@ swiotlb_init_with_default_size(size_t default_size)
         for (i = 0; i < io_tlb_nslabs; i++)
                 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
         io_tlb_index = 0;
-        io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *));
+        io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
 
         /*
          * Get the overflow emergency buffer
@@ -168,8 +224,7 @@ swiotlb_init_with_default_size(size_t default_size)
         if (!io_tlb_overflow_buffer)
                 panic("Cannot allocate SWIOTLB overflow buffer!\n");
 
-        printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n",
-               virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end));
+        swiotlb_print_info(bytes);
 }
 
 void __init
@@ -202,8 +257,7 @@ swiotlb_late_init_with_default_size(size_t default_size)
         bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 
         while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
-                io_tlb_start = (char *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
-                                                        order);
+                io_tlb_start = swiotlb_alloc(order, io_tlb_nslabs);
                 if (io_tlb_start)
                         break;
                 order--;
@@ -235,12 +289,12 @@ swiotlb_late_init_with_default_size(size_t default_size)
                 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
         io_tlb_index = 0;
 
-        io_tlb_orig_addr = (unsigned char **)__get_free_pages(GFP_KERNEL,
-                                   get_order(io_tlb_nslabs * sizeof(char *)));
+        io_tlb_orig_addr = (struct swiotlb_phys_addr *)__get_free_pages(GFP_KERNEL,
+                                   get_order(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr)));
         if (!io_tlb_orig_addr)
                 goto cleanup3;
 
-        memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(char *));
+        memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
 
         /*
          * Get the overflow emergency buffer
@@ -250,9 +304,7 @@ swiotlb_late_init_with_default_size(size_t default_size)
         if (!io_tlb_overflow_buffer)
                 goto cleanup4;
 
-        printk(KERN_INFO "Placing %luMB software IO TLB between 0x%lx - "
-               "0x%lx\n", bytes >> 20,
-               virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end));
+        swiotlb_print_info(bytes);
 
         return 0;
 
@@ -279,16 +331,69 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr, size_t size)
         return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
 }
 
+static inline int range_needs_mapping(void *ptr, size_t size)
+{
+        return swiotlb_force || swiotlb_arch_range_needs_mapping(ptr, size);
+}
+
 static int is_swiotlb_buffer(char *addr)
 {
         return addr >= io_tlb_start && addr < io_tlb_end;
 }
 
+static struct swiotlb_phys_addr swiotlb_bus_to_phys_addr(char *dma_addr)
+{
+        int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
+        struct swiotlb_phys_addr buffer = io_tlb_orig_addr[index];
+        buffer.offset += (long)dma_addr & ((1 << IO_TLB_SHIFT) - 1);
+        buffer.page += buffer.offset >> PAGE_SHIFT;
+        buffer.offset &= PAGE_SIZE - 1;
+        return buffer;
+}
+
+static void
+__sync_single(struct swiotlb_phys_addr buffer, char *dma_addr, size_t size, int dir)
+{
+        if (PageHighMem(buffer.page)) {
+                size_t len, bytes;
+                char *dev, *host, *kmp;
+
+                len = size;
+                while (len != 0) {
+                        unsigned long flags;
+
+                        bytes = len;
+                        if ((bytes + buffer.offset) > PAGE_SIZE)
+                                bytes = PAGE_SIZE - buffer.offset;
+                        local_irq_save(flags); /* protects KM_BOUNCE_READ */
+                        kmp  = kmap_atomic(buffer.page, KM_BOUNCE_READ);
+                        dev  = dma_addr + size - len;
+                        host = kmp + buffer.offset;
+                        if (dir == DMA_FROM_DEVICE)
+                                memcpy(host, dev, bytes);
+                        else
+                                memcpy(dev, host, bytes);
+                        kunmap_atomic(kmp, KM_BOUNCE_READ);
+                        local_irq_restore(flags);
+                        len -= bytes;
+                        buffer.page++;
+                        buffer.offset = 0;
+                }
+        } else {
+                void *v = page_address(buffer.page) + buffer.offset;
+
+                if (dir == DMA_TO_DEVICE)
+                        memcpy(dma_addr, v, size);
+                else
+                        memcpy(v, dma_addr, size);
+        }
+}
+
 /*
  * Allocates bounce buffer and returns its kernel virtual address.
  */
 static void *
-map_single(struct device *hwdev, char *buffer, size_t size, int dir)
+map_single(struct device *hwdev, struct swiotlb_phys_addr buffer, size_t size, int dir)
 {
         unsigned long flags;
         char *dma_addr;
@@ -298,11 +403,16 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
         unsigned long mask;
         unsigned long offset_slots;
         unsigned long max_slots;
+        struct swiotlb_phys_addr slot_buf;
 
         mask = dma_get_seg_boundary(hwdev);
-        start_dma_addr = virt_to_bus(io_tlb_start) & mask;
+        start_dma_addr = swiotlb_virt_to_bus(io_tlb_start) & mask;
 
         offset_slots = ALIGN(start_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+
+        /*
+         * Carefully handle integer overflow which can occur when mask == ~0UL.
+         */
         max_slots = mask + 1
                     ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
                     : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
@@ -378,10 +488,15 @@ found:
          * This is needed when we sync the memory.  Then we sync the buffer if
          * needed.
          */
-        for (i = 0; i < nslots; i++)
-                io_tlb_orig_addr[index+i] = buffer + (i << IO_TLB_SHIFT);
+        slot_buf = buffer;
+        for (i = 0; i < nslots; i++) {
+                slot_buf.page += slot_buf.offset >> PAGE_SHIFT;
+                slot_buf.offset &= PAGE_SIZE - 1;
+                io_tlb_orig_addr[index+i] = slot_buf;
+                slot_buf.offset += 1 << IO_TLB_SHIFT;
+        }
         if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
-                memcpy(dma_addr, buffer, size);
+                __sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);
 
         return dma_addr;
 }
@@ -395,17 +510,17 @@ 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;
         int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
-        char *buffer = io_tlb_orig_addr[index];
+        struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
 
         /*
          * First, sync the memory before unmapping the entry
          */
-        if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+        if ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))
                 /*
                  * bounce... copy the data back into the original buffer * and
                  * delete the bounce buffer.
                  */
-                memcpy(buffer, dma_addr, size);
+                __sync_single(buffer, dma_addr, size, DMA_FROM_DEVICE);
 
         /*
          * Return the buffer to the free list by setting the corresponding
@@ -437,21 +552,18 @@ static void
 sync_single(struct device *hwdev, char *dma_addr, size_t size,
             int dir, int target)
 {
-        int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
-        char *buffer = io_tlb_orig_addr[index];
-
-        buffer += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));
+        struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
 
         switch (target) {
         case SYNC_FOR_CPU:
                 if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
-                        memcpy(buffer, dma_addr, size);
+                        __sync_single(buffer, dma_addr, size, DMA_FROM_DEVICE);
                 else
                         BUG_ON(dir != DMA_TO_DEVICE);
                 break;
         case SYNC_FOR_DEVICE:
                 if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
-                        memcpy(dma_addr, buffer, size);
+                        __sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);
                 else
                         BUG_ON(dir != DMA_FROM_DEVICE);
                 break;
@@ -473,7 +585,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                 dma_mask = hwdev->coherent_dma_mask;
 
         ret = (void *)__get_free_pages(flags, order);
-        if (ret && !is_buffer_dma_capable(dma_mask, virt_to_bus(ret), size)) {
+        if (ret && !is_buffer_dma_capable(dma_mask, swiotlb_virt_to_bus(ret), size)) {
                 /*
                  * The allocated memory isn't reachable by the device.
                  * Fall back on swiotlb_map_single().
@@ -488,13 +600,16 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                  * swiotlb_map_single(), which will grab memory from
                  * the lowest available address range.
                  */
-                ret = map_single(hwdev, NULL, size, DMA_FROM_DEVICE);
+                struct swiotlb_phys_addr buffer;
+                buffer.page = virt_to_page(NULL);
+                buffer.offset = 0;
+                ret = map_single(hwdev, buffer, size, DMA_FROM_DEVICE);
                 if (!ret)
                         return NULL;
         }
 
         memset(ret, 0, size);
-        dev_addr = virt_to_bus(ret);
+        dev_addr = swiotlb_virt_to_bus(ret);
 
         /* Confirm address can be DMA'd by device */
         if (!is_buffer_dma_capable(dma_mask, dev_addr, size)) {
@@ -554,8 +669,9 @@ dma_addr_t
 swiotlb_map_single_attrs(struct device *hwdev, void *ptr, size_t size,
                          int dir, struct dma_attrs *attrs)
 {
-        dma_addr_t dev_addr = virt_to_bus(ptr);
+        dma_addr_t dev_addr = swiotlb_virt_to_bus(ptr);
         void *map;
+        struct swiotlb_phys_addr buffer;
 
         BUG_ON(dir == DMA_NONE);
         /*
@@ -563,19 +679,22 @@ swiotlb_map_single_attrs(struct device *hwdev, void *ptr, size_t size,
          * we can safely return the device addr and not worry about bounce
          * buffering it.
          */
-        if (!address_needs_mapping(hwdev, dev_addr, size) && !swiotlb_force)
+        if (!address_needs_mapping(hwdev, dev_addr, size) &&
+            !range_needs_mapping(ptr, size))
                 return dev_addr;
 
         /*
          * Oh well, have to allocate and map a bounce buffer.
          */
-        map = map_single(hwdev, ptr, size, dir);
+        buffer.page   = virt_to_page(ptr);
+        buffer.offset = (unsigned long)ptr & ~PAGE_MASK;
+        map = map_single(hwdev, buffer, size, dir);
         if (!map) {
                 swiotlb_full(hwdev, size, dir, 1);
                 map = io_tlb_overflow_buffer;
         }
 
-        dev_addr = virt_to_bus(map);
+        dev_addr = swiotlb_virt_to_bus(map);
 
         /*
          * Ensure that the address returned is DMA'ble
@@ -605,7 +724,7 @@ void
 swiotlb_unmap_single_attrs(struct device *hwdev, dma_addr_t dev_addr,
                            size_t size, int dir, struct dma_attrs *attrs)
 {
-        char *dma_addr = bus_to_virt(dev_addr);
+        char *dma_addr = swiotlb_bus_to_virt(dev_addr);
 
         BUG_ON(dir == DMA_NONE);
         if (is_swiotlb_buffer(dma_addr))
@@ -635,7 +754,7 @@ static void
 swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
                     size_t size, int dir, int target)
 {
-        char *dma_addr = bus_to_virt(dev_addr);
+        char *dma_addr = swiotlb_bus_to_virt(dev_addr);
 
         BUG_ON(dir == DMA_NONE);
         if (is_swiotlb_buffer(dma_addr))
@@ -666,7 +785,7 @@ 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 = bus_to_virt(dev_addr) + offset;
+        char *dma_addr = swiotlb_bus_to_virt(dev_addr) + offset;
 
         BUG_ON(dir == DMA_NONE);
         if (is_swiotlb_buffer(dma_addr))
@@ -714,18 +833,20 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
                      int dir, struct dma_attrs *attrs)
 {
         struct scatterlist *sg;
-        void *addr;
+        struct swiotlb_phys_addr buffer;
         dma_addr_t dev_addr;
         int i;
 
         BUG_ON(dir == DMA_NONE);
 
         for_each_sg(sgl, sg, nelems, i) {
-                addr = SG_ENT_VIRT_ADDRESS(sg);
-                dev_addr = virt_to_bus(addr);
-                if (swiotlb_force ||
+                dev_addr = swiotlb_sg_to_bus(sg);
+                if (range_needs_mapping(sg_virt(sg), sg->length) ||
                     address_needs_mapping(hwdev, dev_addr, sg->length)) {
-                        void *map = map_single(hwdev, addr, sg->length, dir);
+                        void *map;
+                        buffer.page   = sg_page(sg);
+                        buffer.offset = sg->offset;
+                        map = map_single(hwdev, buffer, sg->length, dir);
                         if (!map) {
                                 /* Don't panic here, we expect map_sg users
                                    to do proper error handling. */
@@ -735,7 +856,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
                                 sgl[0].dma_length = 0;
                                 return 0;
                         }
-                        sg->dma_address = virt_to_bus(map);
+                        sg->dma_address = swiotlb_virt_to_bus(map);
                 } else
                         sg->dma_address = dev_addr;
                 sg->dma_length = sg->length;
@@ -765,11 +886,11 @@ 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 != SG_ENT_PHYS_ADDRESS(sg))
-                        unmap_single(hwdev, bus_to_virt(sg->dma_address),
+                if (sg->dma_address != swiotlb_sg_to_bus(sg))
+                        unmap_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
                                      sg->dma_length, dir);
                 else if (dir == DMA_FROM_DEVICE)
-                        dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
+                        dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
         }
 }
 EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
@@ -798,11 +919,11 @@ swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
         BUG_ON(dir == DMA_NONE);
 
         for_each_sg(sgl, sg, nelems, i) {
-                if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
-                        sync_single(hwdev, bus_to_virt(sg->dma_address),
+                if (sg->dma_address != swiotlb_sg_to_bus(sg))
+                        sync_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
                                     sg->dma_length, dir, target);
                 else if (dir == DMA_FROM_DEVICE)
-                        dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
+                        dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
         }
 }
 
@@ -823,7 +944,7 @@ swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
 int
 swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
 {
-        return (dma_addr == virt_to_bus(io_tlb_overflow_buffer));
+        return (dma_addr == swiotlb_virt_to_bus(io_tlb_overflow_buffer));
 }
 
 /*
@@ -835,7 +956,7 @@ swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
 int
 swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
-        return virt_to_bus(io_tlb_end - 1) <= mask;
+        return swiotlb_virt_to_bus(io_tlb_end - 1) <= mask;
 }
 
 EXPORT_SYMBOL(swiotlb_map_single);