[PATCH 5.11 16/31] swiotlb: factor out a nr_slots helper

Greg Kroah-Hartman
2021-05-05T12:11:36Z

From: Jianxiong Gao <jxgao@google.com>

commit: c32a77fd18780a5192dfb6eec69f239faebf28fd

Factor out a helper to find the number of slots for a given size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jianxiong Gao <jxgao@google.com>
Tested-by: Jianxiong Gao <jxgao@google.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jianxiong Gao <jxgao@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/dma/swiotlb.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -194,6 +194,11 @@ static inline unsigned long io_tlb_offse
return val & (IO_TLB_SEGSIZE - 1);
}

+static inline unsigned long nr_slots(u64 val)
+{
+ return DIV_ROUND_UP(val, IO_TLB_SIZE);
+}
+
/*
* Early SWIOTLB allocation may be too early to allow an architecture to
* perform the desired operations. This function allows the architecture to
@@ -493,20 +498,20 @@ phys_addr_t swiotlb_tbl_map_single(struc

tbl_dma_addr &= mask;

- offset_slots = ALIGN(tbl_dma_addr, IO_TLB_SIZE) >> IO_TLB_SHIFT;
+ offset_slots = nr_slots(tbl_dma_addr);

/*
* Carefully handle integer overflow which can occur when mask == ~0UL.
*/
max_slots = mask + 1
- ? ALIGN(mask + 1, IO_TLB_SIZE) >> IO_TLB_SHIFT
+ ? nr_slots(mask + 1)
: 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, IO_TLB_SIZE) >> IO_TLB_SHIFT;
+ nslots = nr_slots(alloc_size);
if (alloc_size >= PAGE_SIZE)
stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
else
@@ -602,7 +607,7 @@ void swiotlb_tbl_unmap_single(struct dev
enum dma_data_direction dir, unsigned long attrs)
{
unsigned long flags;
- int i, count, nslots = ALIGN(alloc_size, IO_TLB_SIZE) >> IO_TLB_SHIFT;
+ int i, count, nslots = nr_slots(alloc_size);
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
phys_addr_t orig_addr = io_tlb_orig_addr[index];