swiotlb: Split size parameter to map/unmap APIs

This splits the size parameter to swiotlb_tbl_map_single() and
swiotlb_tbl_unmap_single() into an alloc_size and a mapping_size
parameter, where the latter one is rounded up to the iommu page
size.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

4 files changed, 32 insertions, 20 deletions

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index ae1df496bf38..adcabd9473eb 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -386,8 +386,8 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
          */
         trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
 
-        map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
-                                     attrs);
+        map = swiotlb_tbl_map_single(dev, start_dma_addr, phys,
+                                     size, size, dir, attrs);
         if (map == (phys_addr_t)DMA_MAPPING_ERROR)
                 return DMA_MAPPING_ERROR;
 
@@ -397,7 +397,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
          * Ensure that the address returned is DMA'ble
          */
         if (unlikely(!dma_capable(dev, dev_addr, size))) {
-                swiotlb_tbl_unmap_single(dev, map, size, dir,
+                swiotlb_tbl_unmap_single(dev, map, size, size, dir,
                                 attrs | DMA_ATTR_SKIP_CPU_SYNC);
                 return DMA_MAPPING_ERROR;
         }
@@ -433,7 +433,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
 
         /* NOTE: We use dev_addr here, not paddr! */
         if (is_xen_swiotlb_buffer(dev_addr))
-                swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
+                swiotlb_tbl_unmap_single(hwdev, paddr, size, size, dir, attrs);
 }
 
 static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 361f62bb4a8e..cde3dc18e21a 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -46,13 +46,17 @@ enum dma_sync_target {
 
 extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
                                           dma_addr_t tbl_dma_addr,
-                                          phys_addr_t phys, size_t size,
+                                          phys_addr_t phys,
+                                          size_t mapping_size,
+                                          size_t alloc_size,
                                           enum dma_data_direction dir,
                                           unsigned long attrs);
 
 extern void swiotlb_tbl_unmap_single(struct device *hwdev,
                                      phys_addr_t tlb_addr,
-                                     size_t size, enum dma_data_direction dir,
+                                     size_t mapping_size,
+                                     size_t alloc_size,
+                                     enum dma_data_direction dir,
                                      unsigned long attrs);
 
 extern void swiotlb_tbl_sync_single(struct device *hwdev,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 795c9b095d75..a7f2a0163426 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -297,7 +297,7 @@ void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
                 dma_direct_sync_single_for_cpu(dev, addr, size, dir);
 
         if (unlikely(is_swiotlb_buffer(phys)))
-                swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
+                swiotlb_tbl_unmap_single(dev, phys, size, size, dir, attrs);
 }
 EXPORT_SYMBOL(dma_direct_unmap_page);
 
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9de232229063..796a44f8ef5a 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -444,7 +444,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
 
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
                                    dma_addr_t tbl_dma_addr,
-                                   phys_addr_t orig_addr, size_t size,
+                                   phys_addr_t orig_addr,
+                                   size_t mapping_size,
+                                   size_t alloc_size,
                                    enum dma_data_direction dir,
                                    unsigned long attrs)
 {
@@ -464,6 +466,12 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
                 pr_warn_once("%s is active and system is using DMA bounce buffers\n",
                              sme_active() ? "SME" : "SEV");
 
+        if (mapping_size > alloc_size) {
+                dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
+                              mapping_size, alloc_size);
+                return (phys_addr_t)DMA_MAPPING_ERROR;
+        }
+
         mask = dma_get_seg_boundary(hwdev);
 
         tbl_dma_addr &= mask;
@@ -471,8 +479,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
         offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
 
         /*
-         * Carefully handle integer overflow which can occur when mask == ~0UL.
-         */
+         * 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);
@@ -481,8 +489,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
          * For mappings greater than or equal to a page, we limit the stride
          * (and hence alignment) to a page size.
          */
-        nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
-        if (size >= PAGE_SIZE)
+        nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+        if (alloc_size >= PAGE_SIZE)
                 stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
         else
                 stride = 1;
@@ -547,7 +555,7 @@ not_found:
         spin_unlock_irqrestore(&io_tlb_lock, flags);
         if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
                 dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
-                         size, io_tlb_nslabs, tmp_io_tlb_used);
+                         alloc_size, io_tlb_nslabs, tmp_io_tlb_used);
         return (phys_addr_t)DMA_MAPPING_ERROR;
 found:
         io_tlb_used += nslots;
@@ -562,7 +570,7 @@ found:
                 io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
         if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
             (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
-                swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
+                swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
 
         return tlb_addr;
 }
@@ -571,11 +579,11 @@ found:
  * tlb_addr is the physical address of the bounce buffer to unmap.
  */
 void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
-                              size_t size, enum dma_data_direction dir,
-                              unsigned long attrs)
+                              size_t mapping_size, size_t alloc_size,
+                              enum dma_data_direction dir, unsigned long attrs)
 {
         unsigned long flags;
-        int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+        int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
         int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
         phys_addr_t orig_addr = io_tlb_orig_addr[index];
 
@@ -585,7 +593,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
         if (orig_addr != INVALID_PHYS_ADDR &&
             !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
             ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
-                swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
+                swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);
 
         /*
          * Return the buffer to the free list by setting the corresponding
@@ -665,14 +673,14 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
 
         /* Oh well, have to allocate and map a bounce buffer. */
         *phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),
-                        *phys, size, dir, attrs);
+                        *phys, size, size, dir, attrs);
         if (*phys == (phys_addr_t)DMA_MAPPING_ERROR)
                 return false;
 
         /* Ensure that the address returned is DMA'ble */
         *dma_addr = __phys_to_dma(dev, *phys);
         if (unlikely(!dma_capable(dev, *dma_addr, size))) {
-                swiotlb_tbl_unmap_single(dev, *phys, size, dir,
+                swiotlb_tbl_unmap_single(dev, *phys, size, size, dir,
                         attrs | DMA_ATTR_SKIP_CPU_SYNC);
                 return false;
         }