diff options
| author | Petr Tesarik <petr.tesarik.ext@huawei.com> | 2023-04-06 16:35:39 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2023-04-06 16:45:12 +0200 |
| commit | bbb73a103fbbed6f63cb738d3783261c4241b4b2 (patch) | |
| tree | 084e78c946e80c5b74853c298d73e35c38186656 /kernel/dma/swiotlb.c | |
| parent | swiotlb: fix slot alignment checks (diff) | |
| download | linux-bbb73a103fbbed6f63cb738d3783261c4241b4b2.tar.xz linux-bbb73a103fbbed6f63cb738d3783261c4241b4b2.zip | |
swiotlb: fix a braino in the alignment check fix
The alignment mask in swiotlb_do_find_slots() masks off the high
bits which are not relevant for the alignment, so multiple
requirements are combined with a bitwise OR rather than AND.
In plain English, the stricter the alignment, the more bits must
be set in iotlb_align_mask.
Confusion may arise from the fact that the same variable is also
used to mask off the offset within a swiotlb slot, which is
achieved with a bitwise AND.
Fixes: 0eee5ae10256 ("swiotlb: fix slot alignment checks")
Reported-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/all/CAA42JLa1y9jJ7BgQvXeUYQh-K2mDNHd2BYZ4iZUz33r5zY7oAQ@mail.gmail.com/
Reported-by: Kelsey Steele <kelseysteele@linux.microsoft.com>
Link: https://lore.kernel.org/all/20230405003549.GA21326@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Tested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma/swiotlb.c')
| -rw-r--r-- | kernel/dma/swiotlb.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 5b919ef832b6..dac42a2ad588 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -623,7 +623,7 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index, phys_to_dma_unencrypted(dev, mem->start) & boundary_mask; unsigned long max_slots = get_max_slots(boundary_mask); unsigned int iotlb_align_mask = - dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1); + dma_get_min_align_mask(dev) | alloc_align_mask; unsigned int nslots = nr_slots(alloc_size), stride; unsigned int offset = swiotlb_align_offset(dev, orig_addr); unsigned int index, slots_checked, count = 0, i; @@ -639,8 +639,8 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index, * allocations. */ if (alloc_size >= PAGE_SIZE) - iotlb_align_mask &= PAGE_MASK; - iotlb_align_mask &= alloc_align_mask; + iotlb_align_mask |= ~PAGE_MASK; + iotlb_align_mask &= ~(IO_TLB_SIZE - 1); /* * For mappings with an alignment requirement don't bother looping to |