Commit 2726bf3f authored by Florian Fainelli's avatar Florian Fainelli Committed by Konrad Rzeszutek Wilk
Browse files

swiotlb: Make SWIOTLB_NO_FORCE perform no allocation 



When SWIOTLB_NO_FORCE is used, there should really be no allocations of
default_nslabs to occur since we are not going to use those slabs. If a
platform was somehow setting swiotlb_no_force and a later call to
swiotlb_init() was to be made we would still be proceeding with
allocating the default SWIOTLB size (64MB), whereas if swiotlb=noforce
was set on the kernel command line we would have only allocated 2KB.

This would be inconsistent and the point of initializing default_nslabs
to 1, was intended to allocate the minimum amount of memory possible, so
simply remove that minimal allocation period.

Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent fcf04489

kernel/dma/swiotlb.c

+14 −4
Original line number Diff line number Diff line
@@ -83,12 +83,10 @@ setup_io_tlb_npages(char *str) 
	}

	if (*str == ',')

		++str;

	if (!strcmp(str, "force")) {

	if (!strcmp(str, "force"))

		swiotlb_force = SWIOTLB_FORCE;

	} else if (!strcmp(str, "noforce")) {

	else if (!strcmp(str, "noforce"))

		swiotlb_force = SWIOTLB_NO_FORCE;

		default_nslabs = 1;

	}



	return 0;

}
@@ -174,6 +172,9 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) 
	struct io_tlb_mem *mem;

	size_t alloc_size;



	if (swiotlb_force == SWIOTLB_NO_FORCE)

		return 0;



	/* protect against double initialization */

	if (WARN_ON_ONCE(io_tlb_default_mem))

		return -ENOMEM;
@@ -211,6 +212,9 @@ swiotlb_init(int verbose) 
	size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT);

	void *tlb;



	if (swiotlb_force == SWIOTLB_NO_FORCE)

		return;



	/* Get IO TLB memory from the low pages */

	tlb = memblock_alloc_low(bytes, PAGE_SIZE);

	if (!tlb)
@@ -240,6 +244,9 @@ swiotlb_late_init_with_default_size(size_t default_size) 
	unsigned int order;

	int rc = 0;



	if (swiotlb_force == SWIOTLB_NO_FORCE)

		return 0;



	/*

	 * Get IO TLB memory from the low pages

	 */
@@ -276,6 +283,9 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) 
	unsigned long bytes = nslabs << IO_TLB_SHIFT, i;

	struct io_tlb_mem *mem;



	if (swiotlb_force == SWIOTLB_NO_FORCE)

		return 0;



	/* protect against double initialization */

	if (WARN_ON_ONCE(io_tlb_default_mem))

		return -ENOMEM;