[PATCH 02/10] swiotlb: add a IO_TLB_SIZE define

[Khalid Elmously]

From: Christoph Hellwig <hch at lst.de>

BugLink: https://bugs.launchpad.net/bugs/1943902

Add a new IO_TLB_SIZE define instead open coding it using
IO_TLB_SHIFT all over.

Signed-off-by: Christoph Hellwig <hch at lst.de>
Acked-by: Jianxiong Gao <jxgao at google.com>
Tested-by: Jianxiong Gao <jxgao at google.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
(backported from commit b5d7ccb7aac3895c2138fe0980a109116ce15eff)
[ kmously: Removed part not applicable/needed due to non-existing
 swiotlb_adjust_size() func ]
Signed-off-by: Khalid Elmously <khalid.elmously at canonical.com>
---
 include/linux/swiotlb.h |  1 +
 kernel/dma/swiotlb.c    | 12 ++++++------
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 0a8fced6aaec4..f7aadd297aa98 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -29,6 +29,7 @@ enum swiotlb_force {
  * controllable.
  */
 #define IO_TLB_SHIFT 11
+#define IO_TLB_SIZE (1 << IO_TLB_SHIFT)
 
 extern void swiotlb_init(int verbose);
 int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index f99b79d7e1235..af41300592024 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -479,20 +479,20 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 
 	tbl_dma_addr &= mask;
 
-	offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	offset_slots = ALIGN(tbl_dma_addr, IO_TLB_SIZE) >> 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
+		    ? ALIGN(mask + 1, IO_TLB_SIZE) >> IO_TLB_SHIFT
 		    : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
 
 	/*
 	 * For mappings greater than or equal to a page, we limit the stride
 	 * (and hence alignment) to a page size.
 	 */
-	nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	nslots = ALIGN(alloc_size, IO_TLB_SIZE) >> IO_TLB_SHIFT;
 	if (alloc_size >= PAGE_SIZE)
 		stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
 	else
@@ -586,7 +586,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 			      enum dma_data_direction dir, unsigned long attrs)
 {
 	unsigned long flags;
-	int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+	int i, count, nslots = ALIGN(alloc_size, IO_TLB_SIZE) >> IO_TLB_SHIFT;
 	int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
 	phys_addr_t orig_addr = io_tlb_orig_addr[index];
 
@@ -637,7 +637,7 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
 
 	if (orig_addr == INVALID_PHYS_ADDR)
 		return;
-	orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1);
+	orig_addr += (unsigned long)tlb_addr & (IO_TLB_SIZE - 1);
 
 	switch (target) {
 	case SYNC_FOR_CPU:
@@ -693,7 +693,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
 
 size_t swiotlb_max_mapping_size(struct device *dev)
 {
-	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
+	return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE;
 }
 
 bool is_swiotlb_active(void)
-- 
2.17.1