linux-kernel - [RFC PATCH 7/7] swiotlb: Do not export swiotlb_bounce since there are no external consumers

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Date:	Wed, 03 Oct 2012 17:39:19 -0700
From:	Alexander Duyck <alexander.h.duyck@...el.com>
To:	konrad.wilk@...cle.com, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, rob@...dley.net, akpm@...ux-foundation.org,
	joerg.roedel@....com, bhelgaas@...gle.com, shuahkhan@...il.com
Cc:	linux-kernel@...r.kernel.org, devel@...uxdriverproject.org,
	x86@...nel.org
Subject: [RFC PATCH 7/7] swiotlb: Do not export swiotlb_bounce since there are
	no external consumers

Currently swiotlb is the only consumer for swiotlb_bounce.  Since that is the
case it doesn't make much sense to be exporting it so make it a static
function only.

In addition we can save a few more lines of code by making it so that it
accepts the DMA address as a physical address instead of a virtual one.  This
is the last piece in essentially pushing all of the DMA address values to use
physical addresses in swiotlb.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---

 include/linux/swiotlb.h |    3 ---
 lib/swiotlb.c           |   30 +++++++++++++-----------------
 2 files changed, 13 insertions(+), 20 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index ba1bd38..8e635d1 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -53,9 +53,6 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
 				    enum dma_sync_target target);
 
 /* Accessory functions. */
-extern void swiotlb_bounce(phys_addr_t phys, char *dma_addr, size_t size,
-			   enum dma_data_direction dir);
-
 extern void
 *swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 			dma_addr_t *dma_handle, gfp_t flags);
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 7cfe850..a2ad781 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -351,10 +351,11 @@ static int is_swiotlb_buffer(phys_addr_t paddr)
 /*
  * Bounce: copy the swiotlb buffer back to the original dma location
  */
-void swiotlb_bounce(phys_addr_t phys, char *dma_addr, size_t size,
-		    enum dma_data_direction dir)
+static void swiotlb_bounce(phys_addr_t phys, phys_addr_t dma_addr,
+			   size_t size, enum dma_data_direction dir)
 {
 	unsigned long pfn = PFN_DOWN(phys);
+	unsigned char *vaddr = phys_to_virt(dma_addr);
 
 	if (PageHighMem(pfn_to_page(pfn))) {
 		/* The buffer does not have a mapping.  Map it in and copy */
@@ -369,25 +370,23 @@ void swiotlb_bounce(phys_addr_t phys, char *dma_addr, size_t size,
 			local_irq_save(flags);
 			buffer = kmap_atomic(pfn_to_page(pfn));
 			if (dir == DMA_TO_DEVICE)
-				memcpy(dma_addr, buffer + offset, sz);
+				memcpy(vaddr, buffer + offset, sz);
 			else
-				memcpy(buffer + offset, dma_addr, sz);
+				memcpy(buffer + offset, vaddr, sz);
 			kunmap_atomic(buffer);
 			local_irq_restore(flags);
 
 			size -= sz;
 			pfn++;
-			dma_addr += sz;
+			vaddr += sz;
 			offset = 0;
 		}
+	} else if (dir == DMA_TO_DEVICE) {
+		memcpy(vaddr, phys_to_virt(phys), size);
 	} else {
-		if (dir == DMA_TO_DEVICE)
-			memcpy(dma_addr, phys_to_virt(phys), size);
-		else
-			memcpy(phys_to_virt(phys), dma_addr, size);
+		memcpy(phys_to_virt(phys), vaddr, size);
 	}
 }
-EXPORT_SYMBOL_GPL(swiotlb_bounce);
 
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 				   dma_addr_t tbl_dma_addr,
@@ -489,7 +488,7 @@ found:
 	for (i = 0; i < nslots; i++)
 		io_tlb_orig_addr[index+i] = phys + (i << IO_TLB_SHIFT);
 	if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
-		swiotlb_bounce(phys, phys_to_virt(dma_addr), size, DMA_TO_DEVICE);
+		swiotlb_bounce(phys, dma_addr, size, DMA_TO_DEVICE);
 
 	return dma_addr;
 }
@@ -522,8 +521,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t dma_addr,
 	 * First, sync the memory before unmapping the entry
 	 */
 	if (phys && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
-		swiotlb_bounce(phys, phys_to_virt(dma_addr),
-			       size, DMA_FROM_DEVICE);
+		swiotlb_bounce(phys, dma_addr, size, DMA_FROM_DEVICE);
 
 	/*
 	 * Return the buffer to the free list by setting the corresponding
@@ -564,15 +562,13 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t dma_addr,
 	switch (target) {
 	case SYNC_FOR_CPU:
 		if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
-			swiotlb_bounce(phys, phys_to_virt(dma_addr),
-				       size, DMA_FROM_DEVICE);
+			swiotlb_bounce(phys, 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))
-			swiotlb_bounce(phys, phys_to_virt(dma_addr),
-				       size, DMA_TO_DEVICE);
+			swiotlb_bounce(phys, dma_addr, size, DMA_TO_DEVICE);
 		else
 			BUG_ON(dir != DMA_FROM_DEVICE);
 		break;

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