Commit bbb73a10 authored by Petr Tesarik's avatar Petr Tesarik Committed by Christoph Hellwig

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: 0eee5ae1 ("swiotlb: fix slot alignment checks")
Reported-by: default avatarDexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/all/CAA42JLa1y9jJ7BgQvXeUYQh-K2mDNHd2BYZ4iZUz33r5zY7oAQ@mail.gmail.com/Reported-by: default avatarKelsey Steele <kelseysteele@linux.microsoft.com>
Link: https://lore.kernel.org/all/20230405003549.GA21326@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/Signed-off-by: default avatarPetr Tesarik <petr.tesarik.ext@huawei.com>
Tested-by: default avatarDexuan Cui <decui@microsoft.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 0eee5ae1
...@@ -623,7 +623,7 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index, ...@@ -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; phys_to_dma_unencrypted(dev, mem->start) & boundary_mask;
unsigned long max_slots = get_max_slots(boundary_mask); unsigned long max_slots = get_max_slots(boundary_mask);
unsigned int iotlb_align_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 nslots = nr_slots(alloc_size), stride;
unsigned int offset = swiotlb_align_offset(dev, orig_addr); unsigned int offset = swiotlb_align_offset(dev, orig_addr);
unsigned int index, slots_checked, count = 0, i; unsigned int index, slots_checked, count = 0, i;
...@@ -639,8 +639,8 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index, ...@@ -639,8 +639,8 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index,
* allocations. * allocations.
*/ */
if (alloc_size >= PAGE_SIZE) if (alloc_size >= PAGE_SIZE)
iotlb_align_mask &= PAGE_MASK; iotlb_align_mask |= ~PAGE_MASK;
iotlb_align_mask &= alloc_align_mask; iotlb_align_mask &= ~(IO_TLB_SIZE - 1);
/* /*
* For mappings with an alignment requirement don't bother looping to * For mappings with an alignment requirement don't bother looping to
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment