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Commit 492366f7 authored by Joerg Roedel's avatar Joerg Roedel Committed by Michael S. Tsirkin
Browse files

swiotlb: Add is_swiotlb_active() function 



This function will be used from dma_direct code to determine
the maximum segment size of a dma mapping.

Cc: stable@vger.kernel.org
Reviewed-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent abe420bf

include/linux/swiotlb.h

+6 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, 
void __init swiotlb_exit(void);

unsigned int swiotlb_max_segment(void);

size_t swiotlb_max_mapping_size(struct device *dev);

bool is_swiotlb_active(void);

#else

#define swiotlb_force SWIOTLB_NO_FORCE

static inline bool is_swiotlb_buffer(phys_addr_t paddr)
@@ -100,6 +101,11 @@ static inline size_t swiotlb_max_mapping_size(struct device *dev) 
{

	return SIZE_MAX;

}



static inline bool is_swiotlb_active(void)

{

	return false;

}

#endif /* CONFIG_SWIOTLB */



extern void swiotlb_print_info(void);

kernel/dma/swiotlb.c

+9 −0
Original line number Diff line number Diff line
@@ -667,3 +667,12 @@ size_t swiotlb_max_mapping_size(struct device *dev) 
{

	return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;

}



bool is_swiotlb_active(void)

{

	/*

	 * When SWIOTLB is initialized, even if io_tlb_start points to physical

	 * address zero, io_tlb_end surely doesn't.

	 */

	return io_tlb_end != 0;

}