From 2726bf3ff2520dba61fafc90a055640f7ad54e05 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 22 Mar 2021 18:53:49 -0700 Subject: 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: Florian Fainelli Reviewed-by: Christoph Hellwig Signed-off-by: Konrad Rzeszutek Wilk --- kernel/dma/swiotlb.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 539c76beb52e..0a5b6f7e75bc 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -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; -- cgit v1.2.3