[PATCH] cleanup swiotlb.c a bit

[Jesse Barnes <jbarnes@engr.sgi.com>]

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This patch mostly cleans up trailing whitespace and long lines, but also 
changes a few printks and gets rid of some unnecessary {} blocks.  Does it 
look ok to you David?  I was thinking it might be nice to abstract it 
slightly more to make the swiotlb functions callable from a platform's 
regular PCI mapping routines as needed, since swiotlb assumes that physical 
addresses and bus addresses are the same.

Thanks,
Jesse

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===== arch/ia64/lib/swiotlb.c 1.20 vs edited =====
--- 1.20/arch/ia64/lib/swiotlb.c	2004-10-19 23:41:20 -07:00
+++ edited/arch/ia64/lib/swiotlb.c	2005-01-05 13:59:06 -08:00
@@ -44,41 +44,44 @@
 #define IO_TLB_SEGSIZE	128
 
 /*
- * log of the size of each IO TLB slab.  The number of slabs is command line controllable.
+ * log of the size of each IO TLB slab.  The number of slabs is command line
+ * controllable.
  */
 #define IO_TLB_SHIFT 11
 
 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 API.
+ * 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
+ * API.
  */
 static char *io_tlb_start, *io_tlb_end;
 
 /*
- * The number of IO TLB blocks (in groups of 64) betweeen io_tlb_start and io_tlb_end.
- * This is command line adjustable via setup_io_tlb_npages.
+ * The number of IO TLB blocks (in groups of 64) betweeen io_tlb_start and
+ * io_tlb_end.  This is command line adjustable via setup_io_tlb_npages.
  * Default to 64MB.
  */
 static unsigned long io_tlb_nslabs = 32768;
 
-/* 
+/*
  * When the IOMMU overflows we return a fallback buffer. This sets the size.
  */
 static unsigned long io_tlb_overflow = 32*1024;
 
-void *io_tlb_overflow_buffer; 
+void *io_tlb_overflow_buffer;
 
 /*
- * This is a free list describing the number of free entries available from each index
+ * This is a free list describing the number of free entries available from
+ * each index
  */
 static unsigned int *io_tlb_list;
 static unsigned int io_tlb_index;
 
 /*
- * We need to save away the original address corresponding to a mapped entry for the sync
- * operations.
+ * We need to save away the original address corresponding to a mapped entry
+ * for the sync operations.
  */
 static unsigned char **io_tlb_orig_addr;
 
@@ -88,10 +91,11 @@
 static spinlock_t io_tlb_lock = SPIN_LOCK_UNLOCKED;
 
 static int __init
-setup_io_tlb_npages (char *str)
+setup_io_tlb_npages(char *str)
 {
-	if (isdigit(*str)) { 
-		io_tlb_nslabs = simple_strtoul(str, &str, 0) << (PAGE_SHIFT - IO_TLB_SHIFT);
+	if (isdigit(*str)) {
+		io_tlb_nslabs = simple_strtoul(str, &str, 0) <<
+			(PAGE_SHIFT - IO_TLB_SHIFT);
 		/* avoid tail segment of size < IO_TLB_SEGSIZE */
 		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
 	}
@@ -105,18 +109,19 @@
 /* make io_tlb_overflow tunable too? */
 
 /*
- * Statically reserve bounce buffer space and initialize bounce buffer data structures for
- * the software IO TLB used to implement the PCI DMA API.
+ * Statically reserve bounce buffer space and initialize bounce buffer data
+ * structures for the software IO TLB used to implement the PCI DMA API.
  */
 void
-swiotlb_init (void)
+swiotlb_init(void)
 {
 	unsigned long i;
 
 	/*
 	 * Get IO TLB memory from the low pages
 	 */
-	io_tlb_start = alloc_bootmem_low_pages(io_tlb_nslabs * (1 << IO_TLB_SHIFT));
+	io_tlb_start = alloc_bootmem_low_pages(io_tlb_nslabs *
+					       (1 << IO_TLB_SHIFT));
 	if (!io_tlb_start)
 		panic("Cannot allocate SWIOTLB buffer");
 	io_tlb_end = io_tlb_start + io_tlb_nslabs * (1 << IO_TLB_SHIFT);
@@ -131,28 +136,30 @@
  		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 *));
-	
-	/* 
-	 * Get the overflow emergency buffer 
+
+	/*
+	 * Get the overflow emergency buffer
 	 */
-	io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow); 
+	io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow);
 	printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n",
 	       virt_to_phys(io_tlb_start), virt_to_phys(io_tlb_end));
 }
 
-static inline int address_needs_mapping(struct device *hwdev, dma_addr_t addr)
-{ 
-	dma_addr_t mask = 0xffffffff; 
-	if (hwdev && hwdev->dma_mask) 
-		mask = *hwdev->dma_mask; 
-	return (addr & ~mask) != 0; 		
-} 
+static inline int
+address_needs_mapping(struct device *hwdev, dma_addr_t addr)
+{
+	dma_addr_t mask = 0xffffffff;
+	/* If the device has a mask, use it, otherwise default to 32 bits */
+	if (hwdev && hwdev->dma_mask)
+		mask = *hwdev->dma_mask;
+	return (addr & ~mask) != 0;
+}
 
 /*
  * 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, char *buffer, size_t size, int dir)
 {
 	unsigned long flags;
 	char *dma_addr;
@@ -160,11 +167,11 @@
 	int i;
 
 	/*
-	 * For mappings greater than a page size, we limit the stride (and hence alignment)
-	 * to a page size.
+	 * For mappings greater than 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 > (1 << PAGE_SHIFT))
+	if (size > PAGE_SIZE)
 		stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
 	else
 		stride = 1;
@@ -173,54 +180,55 @@
 		BUG();
 
 	/*
-	 * Find suitable number of IO TLB entries size that will fit this request and
-	 * allocate a buffer from that IO TLB pool.
+	 * Find suitable number of IO TLB entries size that will fit this
+	 * request and allocate a buffer from that IO TLB pool.
 	 */
 	spin_lock_irqsave(&io_tlb_lock, flags);
-	{
-		wrap = index = ALIGN(io_tlb_index, stride);
+	wrap = index = ALIGN(io_tlb_index, stride);
 
-		if (index >= io_tlb_nslabs)
-			wrap = index = 0;
+	if (index >= io_tlb_nslabs)
+		wrap = index = 0;
+
+	do {
+		/*
+		 * If we find a slot that indicates we have 'nslots'
+		 * number of contiguous buffers, we allocate the
+		 * buffers from that slot and mark the entries as '0'
+		 * indicating unavailable.
+		 */
+		if (io_tlb_list[index] >= nslots) {
+			int count = 0;
+
+			for (i = index; i < (int) (index + nslots); i++)
+				io_tlb_list[i] = 0;
+			for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
+				io_tlb_list[i] = ++count;
+			dma_addr = io_tlb_start + (index << IO_TLB_SHIFT);
 
-		do {
 			/*
-			 * If we find a slot that indicates we have 'nslots' number of
-			 * contiguous buffers, we allocate the buffers from that slot and
-			 * mark the entries as '0' indicating unavailable.
+			 * Update the indices to avoid searching in the next
+			 * round.
 			 */
-			if (io_tlb_list[index] >= nslots) {
-				int count = 0;
+			io_tlb_index = ((index + nslots) < io_tlb_nslabs
+					? (index + nslots) : 0);
 
-				for (i = index; i < (int) (index + nslots); i++)
-					io_tlb_list[i] = 0;
-				for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1)
-				       && io_tlb_list[i]; i--)
-					io_tlb_list[i] = ++count;
-				dma_addr = io_tlb_start + (index << IO_TLB_SHIFT);
-
-				/*
-				 * Update the indices to avoid searching in the next round.
-				 */
-				io_tlb_index = ((index + nslots) < io_tlb_nslabs
-						? (index + nslots) : 0);
+			goto found;
+		}
+		index += stride;
+		if (index >= io_tlb_nslabs)
+			index = 0;
+	} while (index != wrap);
 
-				goto found;
-			}
-			index += stride;
-			if (index >= io_tlb_nslabs)
-				index = 0;
-		} while (index != wrap);
+	spin_unlock_irqrestore(&io_tlb_lock, flags);
+	return NULL;
 
-		spin_unlock_irqrestore(&io_tlb_lock, flags);
-		return NULL;
-	}
   found:
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
 
 	/*
-	 * Save away the mapping from the original address to the DMA address.  This is
-	 * needed when we sync the memory.  Then we sync the buffer if needed.
+	 * Save away the mapping from the original address to the DMA address.
+	 * This is needed when we sync the memory.  Then we sync the buffer if
+	 * needed.
 	 */
 	io_tlb_orig_addr[index] = buffer;
 	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
@@ -233,10 +241,10 @@
  * 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)
+unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
 {
 	unsigned long flags;
-	int i, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	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];
 
@@ -245,40 +253,37 @@
 	 */
 	if ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))
 		/*
-		 * bounce... copy the data back into the original buffer * and delete the
-		 * bounce buffer.
+		 * bounce... copy the data back into the original buffer * and
+		 * delete the bounce buffer.
 		 */
 		memcpy(buffer, dma_addr, size);
 
 	/*
-	 * Return the buffer to the free list by setting the corresponding entries to
-	 * indicate the number of contigous entries available.  While returning the
-	 * entries to the free list, we merge the entries with slots below and above the
-	 * pool being returned.
+	 * Return the buffer to the free list by setting the corresponding
+	 * entries to indicate the number of contigous entries available.
+	 * While returning the entries to the free list, we merge the entries
+	 * with slots below and above the pool being returned.
 	 */
 	spin_lock_irqsave(&io_tlb_lock, flags);
-	{
-		int count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
-			     io_tlb_list[index + nslots] : 0);
-		/*
-		 * Step 1: return the slots to the free list, merging the slots with
-		 * superceeding slots
-		 */
-		for (i = index + nslots - 1; i >= index; i--)
-			io_tlb_list[i] = ++count;
-		/*
-		 * Step 2: merge the returned slots with the preceding slots, if
-		 * available (non zero)
-		 */
-		for (i = index - 1;  (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) &&
-		       io_tlb_list[i]; i--)
-			io_tlb_list[i] = ++count;
-	}
+	count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
+		 io_tlb_list[index + nslots] : 0);
+	/*
+	 * Step 1: return the slots to the free list, merging the
+	 * slots with superceeding slots
+	 */
+	for (i = index + nslots - 1; i >= index; i--)
+		io_tlb_list[i] = ++count;
+	/*
+	 * Step 2: merge the returned slots with the preceding slots,
+	 * if available (non zero)
+	 */
+	for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
+		io_tlb_list[i] = ++count;
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
 }
 
 static void
-sync_single (struct device *hwdev, char *dma_addr, size_t size, int dir)
+sync_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
 {
 	int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
 	char *buffer = io_tlb_orig_addr[index];
@@ -296,17 +301,22 @@
 }
 
 void *
-swiotlb_alloc_coherent (struct device *hwdev, size_t size, dma_addr_t *dma_handle, int flags)
+swiotlb_alloc_coherent(struct device *hwdev, size_t size,
+		       dma_addr_t *dma_handle, int flags)
 {
 	unsigned long dev_addr;
 	void *ret;
 
-	/* XXX fix me: the DMA API should pass us an explicit DMA mask instead: */
+	/*
+	 * XXX fix me: the DMA API should pass us an explicit DMA mask
+	 * instead, or use ZONE_DMA32 (ia64 overloads ZONE_DMA to be a ~32
+	 * bit range instead of a 16MB one).
+	 */
 	flags |= GFP_DMA;
 
 	ret = (void *)__get_free_pages(flags, get_order(size));
 	if (!ret) {
-		 /* DMA_FROM_DEVICE is to avoid the memcpy in map_single */
+		/* DMA_FROM_DEVICE is to avoid the memcpy in map_single */
 		dma_addr_t handle;
 		handle = swiotlb_map_single(NULL, NULL, size, DMA_FROM_DEVICE);
 		if (dma_mapping_error(handle))
@@ -317,14 +327,21 @@
 
 	memset(ret, 0, size);
 	dev_addr = virt_to_phys(ret);
-	if (address_needs_mapping(hwdev,dev_addr))
-		panic("swiotlb_alloc_consistent: allocated memory is out of range for device");
+
+	/* Confirm address can be DMA'd by device */
+	if (address_needs_mapping(hwdev, dev_addr)) {
+		printk("hwdev DMA mask = 0x%016lx, dev_addr = 0x%016lx\n",
+		       *hwdev->dma_mask, dev_addr);
+		panic("swiotlb_alloc_coherent: allocated memory is out of "
+		      "range for device");
+	}
 	*dma_handle = dev_addr;
 	return ret;
 }
 
 void
-swiotlb_free_coherent (struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
+swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
+		      dma_addr_t dma_handle)
 {
 	if (!(vaddr >= (void *)io_tlb_start
                     && vaddr < (void *)io_tlb_end))
@@ -334,66 +351,63 @@
 		swiotlb_unmap_single (hwdev, dma_handle, size, DMA_TO_DEVICE);
 }
 
-static void swiotlb_full(struct device *dev, size_t size, int dir, int do_panic)
+static void
+swiotlb_full(struct device *dev, size_t size, int dir, int do_panic)
 {
-	/* 
+	/*
 	 * Ran out of IOMMU space for this operation. This is very bad.
 	 * Unfortunately the drivers cannot handle this operation properly.
 	 * unless they check for pci_dma_mapping_error (most don't)
 	 * When the mapping is small enough return a static buffer to limit
-	 * the damage, or panic when the transfer is too big. 
-	 */ 
-	
-	printk(KERN_ERR 
-  "PCI-DMA: Out of SW-IOMMU space for %lu bytes at device %s\n",
-	       size, dev ? dev->bus_id : "?");
+	 * the damage, or panic when the transfer is too big.
+	 */
+	printk(KERN_ERR "PCI-DMA: Out of SW-IOMMU space for %lu bytes at "
+	       "device %s\n", size, dev ? dev->bus_id : "?");
 
 	if (size > io_tlb_overflow && do_panic) {
 		if (dir == PCI_DMA_FROMDEVICE || dir == PCI_DMA_BIDIRECTIONAL)
 			panic("PCI-DMA: Memory would be corrupted\n");
-		if (dir == PCI_DMA_TODEVICE || dir == PCI_DMA_BIDIRECTIONAL) 
-			panic("PCI-DMA: Random memory would be DMAed\n"); 
-	} 
-} 
+		if (dir == PCI_DMA_TODEVICE || dir == PCI_DMA_BIDIRECTIONAL)
+			panic("PCI-DMA: Random memory would be DMAed\n");
+	}
+}
 
 /*
- * Map a single buffer of the indicated size for DMA in streaming mode.  The PCI address
- * to use is returned.
+ * Map a single buffer of the indicated size for DMA in streaming mode.  The
+ * PCI 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.
+ * 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.
  */
 dma_addr_t
-swiotlb_map_single (struct device *hwdev, void *ptr, size_t size, int dir)
+swiotlb_map_single(struct device *hwdev, void *ptr, size_t size, int dir)
 {
 	unsigned long dev_addr = virt_to_phys(ptr);
-	void *map; 
+	void *map;
 
 	if (dir == DMA_NONE)
 		BUG();
 	/*
-	 * Check if the PCI device can DMA to ptr... if so, just return ptr
+	 * If the pointer passed in 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(hwdev, dev_addr) && !swiotlb_force) 
-		/*
-		 * Device is bit capable of DMA'ing to the buffer... just return the PCI
-		 * address of ptr
-		 */
+	if (!address_needs_mapping(hwdev, dev_addr) && !swiotlb_force)
 		return dev_addr;
 
 	/*
-	 * get a bounce buffer:
+	 * Oh well, have to allocate and map a bounce buffer.
 	 */
 	map = map_single(hwdev, ptr, size, dir);
-	if (!map) { 
-		swiotlb_full(hwdev, size, dir, 1);		
-		map = io_tlb_overflow_buffer; 
+	if (!map) {
+		swiotlb_full(hwdev, size, dir, 1);
+		map = io_tlb_overflow_buffer;
 	}
 
 	dev_addr = virt_to_phys(map);
 
 	/*
-	 * Ensure that the address returned is DMA'ble:
+	 * Ensure that the address returned is DMA'ble
 	 */
 	if (address_needs_mapping(hwdev, dev_addr))
 		panic("map_single: bounce buffer is not DMA'ble");
@@ -407,7 +421,7 @@
  * flush them when they get mapped into an executable vm-area.
  */
 static void
-mark_clean (void *addr, size_t size)
+mark_clean(void *addr, size_t size)
 {
 	unsigned long pg_addr, end;
 
@@ -421,15 +435,16 @@
 }
 
 /*
- * 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 other usages are
- * undefined.
+ * 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
+ * other usages are undefined.
  *
- * After this call, reads by the cpu to the buffer are guaranteed to see whatever the
- * device wrote there.
+ * After this call, reads by the cpu to the buffer are guaranteed to see
+ * whatever the device wrote there.
  */
 void
-swiotlb_unmap_single (struct device *hwdev, dma_addr_t dev_addr, size_t size, int dir)
+swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr, size_t size,
+		     int dir)
 {
 	char *dma_addr = phys_to_virt(dev_addr);
 
@@ -442,16 +457,18 @@
 }
 
 /*
- * Make physical memory consistent for a single streaming mode DMA translation after a
- * transfer.
+ * 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 using the cpu,
- * yet do not wish to teardown the PCI dma mapping, you must call this function before
- * doing so.  At the next point you give the PCI dma address back to the card, you must
- * first perform a swiotlb_dma_sync_for_device, and then the device again owns the buffer
+ * If you perform a swiotlb_map_single() but wish to interrogate the buffer
+ * using the cpu, yet do not wish to teardown the PCI dma mapping, you must
+ * call this function before doing so.  At the next point you give the PCI dma
+ * address back to the card, you must first perform a
+ * swiotlb_dma_sync_for_device, and then the device again owns the buffer
  */
 void
-swiotlb_sync_single_for_cpu (struct device *hwdev, dma_addr_t dev_addr, size_t size, int dir)
+swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
+			    size_t size, int dir)
 {
 	char *dma_addr = phys_to_virt(dev_addr);
 
@@ -464,7 +481,8 @@
 }
 
 void
-swiotlb_sync_single_for_device (struct device *hwdev, dma_addr_t dev_addr, size_t size, int dir)
+swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
+			       size_t size, int dir)
 {
 	char *dma_addr = phys_to_virt(dev_addr);
 
@@ -477,10 +495,11 @@
 }
 
 /*
- * 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 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).
+ * 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
+ * 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).
  *
  * NOTE: An implementation may be able to use a smaller number of
  *       DMA address/length pairs than there are SG table elements.
@@ -488,10 +507,12 @@
  *       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 same here.
+ * Device ownership issues as mentioned above for swiotlb_map_single are the
+ * same here.
  */
 int
-swiotlb_map_sg (struct device *hwdev, struct scatterlist *sg, int nelems, int dir)
+swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
+	       int dir)
 {
 	void *addr;
 	unsigned long dev_addr;
@@ -506,9 +527,9 @@
 		if (swiotlb_force || address_needs_mapping(hwdev, dev_addr)) {
 			sg->dma_address = (dma_addr_t) virt_to_phys(map_single(hwdev, addr, sg->length, dir));
 			if (!sg->dma_address) {
-				/* Don't panic here, we expect pci_map_sg users
+				/* Don't panic here, we expect map_sg users
 				   to do proper error handling. */
-				swiotlb_full(hwdev, sg->length, dir, 0); 
+				swiotlb_full(hwdev, sg->length, dir, 0);
 				swiotlb_unmap_sg(hwdev, sg - i, i, dir);
 				sg[0].dma_length = 0;
 				return 0;
@@ -521,11 +542,12 @@
 }
 
 /*
- * Unmap a set of streaming mode DMA translations.  Again, cpu read rules concerning calls
- * here are the same as for swiotlb_unmap_single() above.
+ * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
+ * concerning calls here are the same as for swiotlb_unmap_single() above.
  */
 void
-swiotlb_unmap_sg (struct device *hwdev, struct scatterlist *sg, int nelems, int dir)
+swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nelems,
+		 int dir)
 {
 	int i;
 
@@ -540,14 +562,15 @@
 }
 
 /*
- * Make physical memory consistent for a set of streaming mode DMA translations after a
- * transfer.
+ * Make physical memory consistent for a set of streaming mode DMA translations
+ * after a transfer.
  *
- * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules and
- * usage.
+ * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
+ * and usage.
  */
 void
-swiotlb_sync_sg_for_cpu (struct device *hwdev, struct scatterlist *sg, int nelems, int dir)
+swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
+			int nelems, int dir)
 {
 	int i;
 
@@ -556,11 +579,13 @@
 
 	for (i = 0; i < nelems; i++, sg++)
 		if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
-			sync_single(hwdev, (void *) sg->dma_address, sg->dma_length, dir);
+			sync_single(hwdev, (void *) sg->dma_address,
+				    sg->dma_length, dir);
 }
 
 void
-swiotlb_sync_sg_for_device (struct device *hwdev, struct scatterlist *sg, int nelems, int dir)
+swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
+			   int nelems, int dir)
 {
 	int i;
 
@@ -569,19 +594,21 @@
 
 	for (i = 0; i < nelems; i++, sg++)
 		if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
-			sync_single(hwdev, (void *) sg->dma_address, sg->dma_length, dir);
+			sync_single(hwdev, (void *) sg->dma_address,
+				    sg->dma_length, dir);
 }
 
 int
-swiotlb_dma_mapping_error (dma_addr_t dma_addr)
+swiotlb_dma_mapping_error(dma_addr_t dma_addr)
 {
 	return (dma_addr == virt_to_phys(io_tlb_overflow_buffer));
 }
 
 /*
- * Return whether the given PCI device DMA address mask can be supported properly.  For
- * example, if your device can only drive the low 24-bits during PCI bus mastering, then
- * you would pass 0x00ffffff as the mask to this function.
+ * Return whether the given PCI device DMA address mask can be supported
+ * properly.  For example, if your device can only drive the low 24-bits
+ * during PCI bus mastering, then you would pass 0x00ffffff as the mask to
+ * this function.
  */
 int
 swiotlb_dma_supported (struct device *hwdev, u64 mask)