dma-mapping fixes for Linux 6.3

- fix for swiotlb deadlock due to wrong alignment checks (GuoRui.Yu,
    Petr Tesarik)
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Merge tag 'dma-mapping-6.3-2023-03-31' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:

 - fix for swiotlb deadlock due to wrong alignment checks (GuoRui.Yu,
   Petr Tesarik)

* tag 'dma-mapping-6.3-2023-03-31' of git://git.infradead.org/users/hch/dma-mapping:
  swiotlb: fix slot alignment checks
  swiotlb: use wrap_area_index() instead of open-coding it
  swiotlb: fix the deadlock in swiotlb_do_find_slots
This commit is contained in:
Linus Torvalds 2023-03-30 16:09:37 -07:00
commit 62bad54b26

View File

@ -625,8 +625,8 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index,
unsigned int iotlb_align_mask =
dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1);
unsigned int nslots = nr_slots(alloc_size), stride;
unsigned int index, wrap, count = 0, i;
unsigned int offset = swiotlb_align_offset(dev, orig_addr);
unsigned int index, slots_checked, count = 0, i;
unsigned long flags;
unsigned int slot_base;
unsigned int slot_index;
@ -634,30 +634,35 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index,
BUG_ON(!nslots);
BUG_ON(area_index >= mem->nareas);
/*
* For allocations of PAGE_SIZE or larger only look for page aligned
* allocations.
*/
if (alloc_size >= PAGE_SIZE)
iotlb_align_mask &= PAGE_MASK;
iotlb_align_mask &= alloc_align_mask;
/*
* For mappings with an alignment requirement don't bother looping to
* unaligned slots once we found an aligned one. For allocations of
* PAGE_SIZE or larger only look for page aligned allocations.
* unaligned slots once we found an aligned one.
*/
stride = (iotlb_align_mask >> IO_TLB_SHIFT) + 1;
if (alloc_size >= PAGE_SIZE)
stride = max(stride, stride << (PAGE_SHIFT - IO_TLB_SHIFT));
stride = max(stride, (alloc_align_mask >> IO_TLB_SHIFT) + 1);
spin_lock_irqsave(&area->lock, flags);
if (unlikely(nslots > mem->area_nslabs - area->used))
goto not_found;
slot_base = area_index * mem->area_nslabs;
index = wrap = wrap_area_index(mem, ALIGN(area->index, stride));
index = area->index;
do {
for (slots_checked = 0; slots_checked < mem->area_nslabs; ) {
slot_index = slot_base + index;
if (orig_addr &&
(slot_addr(tbl_dma_addr, slot_index) &
iotlb_align_mask) != (orig_addr & iotlb_align_mask)) {
index = wrap_area_index(mem, index + 1);
slots_checked++;
continue;
}
@ -673,7 +678,8 @@ static int swiotlb_do_find_slots(struct device *dev, int area_index,
goto found;
}
index = wrap_area_index(mem, index + stride);
} while (index != wrap);
slots_checked += stride;
}
not_found:
spin_unlock_irqrestore(&area->lock, flags);
@ -693,10 +699,7 @@ found:
/*
* Update the indices to avoid searching in the next round.
*/
if (index + nslots < mem->area_nslabs)
area->index = index + nslots;
else
area->index = 0;
area->index = wrap_area_index(mem, index + nslots);
area->used += nslots;
spin_unlock_irqrestore(&area->lock, flags);
return slot_index;