Commit c32a77fd authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Konrad Rzeszutek Wilk
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swiotlb: factor out a nr_slots helper 



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

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarJianxiong Gao <jxgao@google.com>
Tested-by: default avatarJianxiong Gao <jxgao@google.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent c7fbeca7

kernel/dma/swiotlb.c

+9 −4
Original line number Diff line number Diff line
@@ -194,6 +194,11 @@ static inline unsigned long io_tlb_offset(unsigned long val) 
	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(struct device *hwdev, phys_addr_t orig_addr, 


	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 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, 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];