X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fswiotlb.c;h=025922807e6e648bb7dc4eda61bfd8fa609a221c;hb=4f02f8220562591322c118d07a32bebf705318b7;hp=1a8050ade86159877fd6eb4486954c7719bfc28d;hpb=4c5cdb1e1f2a502069f57a60b5c6b97b8106c73c;p=linux-2.6

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 1a8050ade8..025922807e 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -282,6 +282,15 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr)
 	return (addr & ~mask) != 0;
 }
 
+static inline unsigned int is_span_boundary(unsigned int index,
+					    unsigned int nslots,
+					    unsigned long offset_slots,
+					    unsigned long max_slots)
+{
+	unsigned long offset = (offset_slots + index) & (max_slots - 1);
+	return offset + nslots > max_slots;
+}
+
 /*
  * Allocates bounce buffer and returns its kernel virtual address.
  */
@@ -292,6 +301,18 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
 	char *dma_addr;
 	unsigned int nslots, stride, index, wrap;
 	int i;
+	unsigned long start_dma_addr;
+	unsigned long mask;
+	unsigned long offset_slots;
+	unsigned long max_slots;
+
+	mask = dma_get_seg_boundary(hwdev);
+	start_dma_addr = virt_to_bus(io_tlb_start) & mask;
+
+	offset_slots = ALIGN(start_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	max_slots = mask + 1
+		    ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
+		    : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
 
 	/*
 	 * For mappings greater than a page, we limit the stride (and
@@ -311,12 +332,21 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
 	 */
 	spin_lock_irqsave(&io_tlb_lock, flags);
 	{
-		wrap = index = ALIGN(io_tlb_index, stride);
-
+		index = ALIGN(io_tlb_index, stride);
 		if (index >= io_tlb_nslabs)
-			wrap = index = 0;
+			index = 0;
+		wrap = index;
 
 		do {
+			while (is_span_boundary(index, nslots, offset_slots,
+						max_slots)) {
+				index += stride;
+				if (index >= io_tlb_nslabs)
+					index = 0;
+				if (index == wrap)
+					goto not_found;
+			}
+
 			/*
 			 * If we find a slot that indicates we have 'nslots'
 			 * number of contiguous buffers, we allocate the
@@ -346,6 +376,7 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
 				index = 0;
 		} while (index != wrap);
 
+  not_found:
 		spin_unlock_irqrestore(&io_tlb_lock, flags);
 		return NULL;
 	}