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authorLinus Torvalds <torvalds@linux-foundation.org>2023-07-09 10:24:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-07-09 10:24:22 -0700
commitf71f64210d698f603ab119740d1656f7bdfd3171 (patch)
tree31940a31dff428f0d49fef1bc1da1fd20c7b9d9f
parenta9943ad3dddb04763e73649ade8ed726a17b5ec3 (diff)
parent8ac04063354a01a484d2e55d20ed1958aa0d3392 (diff)
Merge tag 'dma-mapping-6.5-2023-07-09' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig: - swiotlb area sizing fixes (Petr Tesarik) * tag 'dma-mapping-6.5-2023-07-09' of git://git.infradead.org/users/hch/dma-mapping: swiotlb: reduce the number of areas to match actual memory pool size swiotlb: always set the number of areas before allocating the pool
-rw-r--r--kernel/dma/swiotlb.c46
1 files changed, 35 insertions, 11 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 775f7bb10ab1..2b83e3ad9dca 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -115,9 +115,16 @@ static bool round_up_default_nslabs(void)
return true;
}
+/**
+ * swiotlb_adjust_nareas() - adjust the number of areas and slots
+ * @nareas: Desired number of areas. Zero is treated as 1.
+ *
+ * Adjust the default number of areas in a memory pool.
+ * The default size of the memory pool may also change to meet minimum area
+ * size requirements.
+ */
static void swiotlb_adjust_nareas(unsigned int nareas)
{
- /* use a single area when non is specified */
if (!nareas)
nareas = 1;
else if (!is_power_of_2(nareas))
@@ -131,6 +138,23 @@ static void swiotlb_adjust_nareas(unsigned int nareas)
(default_nslabs << IO_TLB_SHIFT) >> 20);
}
+/**
+ * limit_nareas() - get the maximum number of areas for a given memory pool size
+ * @nareas: Desired number of areas.
+ * @nslots: Total number of slots in the memory pool.
+ *
+ * Limit the number of areas to the maximum possible number of areas in
+ * a memory pool of the given size.
+ *
+ * Return: Maximum possible number of areas.
+ */
+static unsigned int limit_nareas(unsigned int nareas, unsigned long nslots)
+{
+ if (nslots < nareas * IO_TLB_SEGSIZE)
+ return nslots / IO_TLB_SEGSIZE;
+ return nareas;
+}
+
static int __init
setup_io_tlb_npages(char *str)
{
@@ -290,6 +314,7 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
{
struct io_tlb_mem *mem = &io_tlb_default_mem;
unsigned long nslabs;
+ unsigned int nareas;
size_t alloc_size;
void *tlb;
@@ -298,18 +323,16 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
if (swiotlb_force_disable)
return;
- /*
- * default_nslabs maybe changed when adjust area number.
- * So allocate bounce buffer after adjusting area number.
- */
if (!default_nareas)
swiotlb_adjust_nareas(num_possible_cpus());
nslabs = default_nslabs;
+ nareas = limit_nareas(default_nareas, nslabs);
while ((tlb = swiotlb_memblock_alloc(nslabs, flags, remap)) == NULL) {
if (nslabs <= IO_TLB_MIN_SLABS)
return;
nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
+ nareas = limit_nareas(nareas, nslabs);
}
if (default_nslabs != nslabs) {
@@ -355,6 +378,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask,
{
struct io_tlb_mem *mem = &io_tlb_default_mem;
unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
+ unsigned int nareas;
unsigned char *vstart = NULL;
unsigned int order, area_order;
bool retried = false;
@@ -363,6 +387,9 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask,
if (swiotlb_force_disable)
return 0;
+ if (!default_nareas)
+ swiotlb_adjust_nareas(num_possible_cpus());
+
retry:
order = get_order(nslabs << IO_TLB_SHIFT);
nslabs = SLABS_PER_PAGE << order;
@@ -397,11 +424,8 @@ retry:
(PAGE_SIZE << order) >> 20);
}
- if (!default_nareas)
- swiotlb_adjust_nareas(num_possible_cpus());
-
- area_order = get_order(array_size(sizeof(*mem->areas),
- default_nareas));
+ nareas = limit_nareas(default_nareas, nslabs);
+ area_order = get_order(array_size(sizeof(*mem->areas), nareas));
mem->areas = (struct io_tlb_area *)
__get_free_pages(GFP_KERNEL | __GFP_ZERO, area_order);
if (!mem->areas)
@@ -415,7 +439,7 @@ retry:
set_memory_decrypted((unsigned long)vstart,
(nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT);
swiotlb_init_io_tlb_mem(mem, virt_to_phys(vstart), nslabs, 0, true,
- default_nareas);
+ nareas);
swiotlb_print_info();
return 0;