linux/kernel/dma
Petr Tesarik 0eee5ae102 swiotlb: fix slot alignment checks
Explicit alignment and page alignment are used only to calculate
the stride, not when checking actual slot physical address.

Originally, only page alignment was implemented, and that worked,
because the whole SWIOTLB is allocated on a page boundary, so
aligning the start index was sufficient to ensure a page-aligned
slot.

When commit 1f221a0d0d ("swiotlb: respect min_align_mask") added
support for min_align_mask, the index could be incremented in the
search loop, potentially finding an unaligned slot if minimum device
alignment is between IO_TLB_SIZE and PAGE_SIZE.  The bug could go
unnoticed, because the slot size is 2 KiB, and the most common page
size is 4 KiB, so there is no alignment value in between.

IIUC the intention has been to find a slot that conforms to all
alignment constraints: device minimum alignment, an explicit
alignment (given as function parameter) and optionally page
alignment (if allocation size is >= PAGE_SIZE). The most
restrictive mask can be trivially computed with logical AND. The
rest can stay.

Fixes: 1f221a0d0d ("swiotlb: respect min_align_mask")
Fixes: e81e99bacc ("swiotlb: Support aligned swiotlb buffers")
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2023-03-22 09:03:17 +01:00
..
coherent.c dma-mapping: Add dma_release_coherent_memory to DMA API 2022-06-24 09:30:54 -06:00
contiguous.c cma: factor out minimum alignment requirement 2022-03-22 15:57:05 -07:00
debug.c dma-debug: improve search for partial syncs 2022-09-07 10:38:16 +02:00
debug.h dma-debug: teach add_dma_entry() about DMA_ATTR_SKIP_CPU_SYNC 2021-10-18 12:46:45 +02:00
direct.c dma-mapping updates 2022-08-06 10:56:45 -07:00
direct.h dma-direct: support PCI P2PDMA pages in dma-direct map_sg 2022-07-26 07:27:47 -04:00
dummy.c dma-mapping: return error code from dma_dummy_map_sg() 2021-08-09 17:13:06 +02:00
Kconfig dma-mapping: remove CONFIG_DMA_REMAP 2022-03-03 14:00:57 +03:00
Makefile dma-mapping: remove CONFIG_DMA_REMAP 2022-03-03 14:00:57 +03:00
map_benchmark.c dma-mapping: benchmark: extract a common header file for map_benchmark definition 2022-03-10 07:41:14 +01:00
mapping.c dma-mapping: reject GFP_COMP for noncoherent allocations 2022-12-21 08:45:38 +01:00
ops_helpers.c dma-mapping: handle vmalloc addresses in dma_common_{mmap,get_sgtable} 2021-07-16 11:30:26 +02:00
pool.c dma/pool: create dma atomic pool only if dma zone has managed pages 2022-01-15 16:30:29 +02:00
remap.c kernel/dma: remove unnecessary unmap_kernel_range 2021-04-30 11:20:40 -07:00
swiotlb.c swiotlb: fix slot alignment checks 2023-03-22 09:03:17 +01:00