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swiotlb: do not try to allocate a TLB bigger than MAX_ORDER pages

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When allocating a new pool at runtime, reduce the number of slabs so
that the allocation order is at most MAX_ORDER.  This avoids a kernel
warning in __alloc_pages().

The warning is relatively benign, because the pool size is subsequently
reduced when allocation fails, but it is silly to start with a request
that is known to fail, especially since this is the default behavior if
the kernel is built with CONFIG_SWIOTLB_DYNAMIC=y and booted without any
swiotlb= parameter.

Reported-by: Ben Greear <greearb@candelatech.com>
Closes: https://lore.kernel.org/netdev/4f173dd2-324a-0240-ff8d-abf5c191be18@candelatech.com/
Fixes: 1aaa736815 ("swiotlb: allocate a new memory pool when existing pools are full")
Signed-off-by: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Petr Tesarik 2023-10-25 10:44:25 +02:00 committed by Christoph Hellwig
parent 4f82870119
commit d5090484b0
1 changed files with 5 additions and 0 deletions
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5
kernel/dma/swiotlb.c
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@ -678,6 +678,11 @@ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev,
size_t pool_size;
size_t tlb_size;
if (nslabs > SLABS_PER_PAGE << MAX_ORDER) {
nslabs = SLABS_PER_PAGE << MAX_ORDER;
nareas = limit_nareas(nareas, nslabs);
}
pool_size = sizeof(*pool) + array_size(sizeof(*pool->areas), nareas);
pool = kzalloc(pool_size, gfp);
if (!pool)