[PATCH 03/10] swiotlb: factor out an io_tlb_offset helper

[Khalid Elmously]

From: Christoph Hellwig <hch at lst.de>

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

Replace the very genericly named OFFSET macro with a little inline
helper that hardcodes the alignment to the only value ever passed.

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>
(cherry picked from commit c7fbeca757fe74135d8b6a4c8ddaef76f5775d68)
Signed-off-by: Khalid Elmously <khalid.elmously at canonical.com>
---
 kernel/dma/swiotlb.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index af41300592024..db265dc324b99 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -49,9 +49,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/swiotlb.h>
 
-#define OFFSET(val,align) ((unsigned long)	\
-	                   ( (val) & ( (align) - 1)))
-
 #define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
 
 /*
@@ -177,6 +174,11 @@ void swiotlb_print_info(void)
 	       bytes >> 20);
 }
 
+static inline unsigned long io_tlb_offset(unsigned long val)
+{
+	return val & (IO_TLB_SEGSIZE - 1);
+}
+
 /*
  * Early SWIOTLB allocation may be too early to allow an architecture to
  * perform the desired operations.  This function allows the architecture to
@@ -226,7 +228,7 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 		      __func__, alloc_size, PAGE_SIZE);
 
 	for (i = 0; i < io_tlb_nslabs; i++) {
-		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+		io_tlb_list[i] = IO_TLB_SEGSIZE - io_tlb_offset(i);
 		io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
 	}
 	io_tlb_index = 0;
@@ -360,7 +362,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 		goto cleanup4;
 
 	for (i = 0; i < io_tlb_nslabs; i++) {
-		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+		io_tlb_list[i] = IO_TLB_SEGSIZE - io_tlb_offset(i);
 		io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
 	}
 	io_tlb_index = 0;
@@ -534,7 +536,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 
 			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--)
+			for (i = index - 1;
+			     io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
+			     io_tlb_list[i]; i--)
 				io_tlb_list[i] = ++count;
 			tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);
 
@@ -620,7 +624,9 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
 		 * 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--)
+		for (i = index - 1;
+		     io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
+		     io_tlb_list[i]; i--)
 			io_tlb_list[i] = ++count;
 
 		io_tlb_used -= nslots;
-- 
2.17.1