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 <f.faine...@gmail.com>
---
Changes in v3:
- patch all call sites that can allocate SWIOTLB memory
Changes in v2:
- rebased against devel/for-linus-5.13
- updated commit message to reflect variable names
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;
--
2.25.1
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
