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dma-mapping: fix missing clear bdr in check_ram_in_range_map()

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As discussed in [1], if 'bdr' is set once, it would never get
cleared, hence 0 is always returned.

Refactor the range check hunk into a new helper dma_find_range(),
which allows 'bdr' to be cleared in each iteration.

Link: https://lore.kernel.org/all/64931fac-085b-4ff3-9314-84bac2fa9bdb@quicinc.com/ # [1]
Fixes: a409d9600959 ("dma-mapping: fix dma_addressing_limited() if dma_range_map can't cover all system RAM")
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Link: https://lore.kernel.org/r/20250307030350.69144-1-quic_bqiang@quicinc.com
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
This commit is contained in:
Baochen Qiang 2025-03-07 11:03:50 +08:00 committed by Marek Szyprowski
parent 2014c95afe
commit 8324993f60
1 changed files with 18 additions and 10 deletions
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28
kernel/dma/direct.c
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@ -584,6 +584,22 @@ int dma_direct_supported(struct device *dev, u64 mask)
return mask >= phys_to_dma_unencrypted(dev, min_mask);
}
static const struct bus_dma_region *dma_find_range(struct device *dev,
unsigned long start_pfn)
{
const struct bus_dma_region *m;
for (m = dev->dma_range_map; PFN_DOWN(m->size); m++) {
unsigned long cpu_start_pfn = PFN_DOWN(m->cpu_start);
if (start_pfn >= cpu_start_pfn &&
start_pfn - cpu_start_pfn < PFN_DOWN(m->size))
return m;
}
return NULL;
}
/*
* To check whether all ram resource ranges are covered by dma range map
* Returns 0 when further check is needed
@ -593,20 +609,12 @@ static int check_ram_in_range_map(unsigned long start_pfn,
unsigned long nr_pages, void *data)
{
unsigned long end_pfn = start_pfn + nr_pages;
const struct bus_dma_region *bdr = NULL;
const struct bus_dma_region *m;
struct device *dev = data;
while (start_pfn < end_pfn) {
for (m = dev->dma_range_map; PFN_DOWN(m->size); m++) {
unsigned long cpu_start_pfn = PFN_DOWN(m->cpu_start);
const struct bus_dma_region *bdr;
if (start_pfn >= cpu_start_pfn &&
start_pfn - cpu_start_pfn < PFN_DOWN(m->size)) {
bdr = m;
break;
}
}
bdr = dma_find_range(dev, start_pfn);
if (!bdr)
return 1;