swiotlb: Export swioltb_nr_tbl and utilize it as appropiate. (5f98ecdb) · Commits · 戴 / test

By default the io_tlb_nslabs is set to zero, and gets set to whatever value is passed in via swiotlb_init_with_tbl function. The default value passed in is 64MB. However, if the user provides the 'swiotlb=<nslabs>' the default value is ignored and the value provided by the user is used... Except when the SWIOTLB is used under Xen - there the default value of 64MB is used and the Xen-SWIOTLB has no mechanism to get the 'io_tlb_nslabs' filled out by setup_io_tlb_npages functions. This patch provides a function for the Xen-SWIOTLB to call to see if the io_tlb_nslabs is set and if so use that value. Signed-off-by:

FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by:

Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/swiotlb-xen.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -147,9 +147,15 @@ void __init xen_swiotlb_init(int verbose)
		{
		unsigned long bytes;
		int rc;
		unsigned long nr_tbl;

		nr_tbl = swioltb_nr_tbl();
		if (nr_tbl)
		xen_io_tlb_nslabs = nr_tbl;
		else {
		xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
		xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
		}

		bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;

include/linux/swiotlb.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@ extern int swiotlb_force;

		extern void swiotlb_init(int verbose);
		extern void swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
		extern unsigned long swioltb_nr_tbl(void);

		/*
		* Enumeration for sync targets

lib/swiotlb.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -110,6 +110,11 @@ setup_io_tlb_npages(char *str)
		__setup("swiotlb=", setup_io_tlb_npages);
		/* make io_tlb_overflow tunable too? */

		unsigned long swioltb_nr_tbl(void)
		{
		return io_tlb_nslabs;
		}

		/* Note that this doesn't work with highmem page */
		static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
		volatile void *address)

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