From 72311809031217714e635b24f8478e6ecb0d93d9 Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Thu, 21 Jul 2022 23:38:46 -0400 Subject: swiotlb: clean up some coding style and minor issues - Fix the used field of struct io_tlb_area wasn't initialized - Set area number to be 0 if input area number parameter is 0 - Use array_size() to calculate io_tlb_area array size - Make parameters of swiotlb_do_find_slots() more reasonable Fixes: 26ffb91fa5e0 ("swiotlb: split up the global swiotlb lock") Signed-off-by: Tianyu Lan Reviewed-by: Michael Kelley Signed-off-by: Christoph Hellwig --- Documentation/admin-guide/kernel-parameters.txt | 3 ++- kernel/dma/swiotlb.c | 26 ++++++++++++++----------- 2 files changed, 17 insertions(+), 12 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 4a6ad177d4b8..ddca09550f76 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5907,7 +5907,8 @@ Format: { [,] | force | noforce } -- Number of I/O TLB slabs -- Second integer after comma. Number of swiotlb - areas with their own lock. Must be power of 2. + areas with their own lock. Will be rounded up + to a power of 2. force -- force using of bounce buffers even if they wouldn't be automatically used by the kernel noforce -- Never use bounce buffers (for debugging) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 39dee4004439..cc50f1fb127f 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -119,7 +119,10 @@ static bool round_up_default_nslabs(void) static void swiotlb_adjust_nareas(unsigned int nareas) { - if (!is_power_of_2(nareas)) + /* use a single area when non is specified */ + if (!nareas) + nareas = 1; + else if (!is_power_of_2(nareas)) nareas = roundup_pow_of_two(nareas); default_nareas = nareas; @@ -276,6 +279,7 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start, for (i = 0; i < mem->nareas; i++) { spin_lock_init(&mem->areas[i].lock); mem->areas[i].index = 0; + mem->areas[i].used = 0; } for (i = 0; i < mem->nslabs; i++) { @@ -358,8 +362,8 @@ retry: panic("%s: Failed to allocate %zu bytes align=0x%lx\n", __func__, alloc_size, PAGE_SIZE); - mem->areas = memblock_alloc(sizeof(struct io_tlb_area) * - default_nareas, SMP_CACHE_BYTES); + mem->areas = memblock_alloc(array_size(sizeof(struct io_tlb_area), + default_nareas), SMP_CACHE_BYTES); if (!mem->areas) panic("%s: Failed to allocate mem->areas.\n", __func__); @@ -484,7 +488,7 @@ void __init swiotlb_exit(void) free_pages((unsigned long)mem->slots, get_order(slots_size)); } else { memblock_free_late(__pa(mem->areas), - mem->nareas * sizeof(struct io_tlb_area)); + array_size(sizeof(*mem->areas), mem->nareas)); memblock_free_late(mem->start, tbl_size); memblock_free_late(__pa(mem->slots), slots_size); } @@ -598,11 +602,12 @@ static unsigned int wrap_area_index(struct io_tlb_mem *mem, unsigned int index) * Find a suitable number of IO TLB entries size that will fit this request and * allocate a buffer from that IO TLB pool. */ -static int swiotlb_do_find_slots(struct io_tlb_mem *mem, - struct io_tlb_area *area, int area_index, - struct device *dev, phys_addr_t orig_addr, - size_t alloc_size, unsigned int alloc_align_mask) +static int swiotlb_do_find_slots(struct device *dev, int area_index, + phys_addr_t orig_addr, size_t alloc_size, + unsigned int alloc_align_mask) { + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + struct io_tlb_area *area = mem->areas + area_index; unsigned long boundary_mask = dma_get_seg_boundary(dev); dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(dev, mem->start) & boundary_mask; @@ -691,12 +696,11 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask) { struct io_tlb_mem *mem = dev->dma_io_tlb_mem; - int start = raw_smp_processor_id() & ((1U << __fls(mem->nareas)) - 1); + int start = raw_smp_processor_id() & (mem->nareas - 1); int i = start, index; do { - index = swiotlb_do_find_slots(mem, mem->areas + i, i, - dev, orig_addr, alloc_size, + index = swiotlb_do_find_slots(dev, i, orig_addr, alloc_size, alloc_align_mask); if (index >= 0) return index; -- cgit v1.2.3