swiotlb: Preserve allocation virtual address for dynamic pools

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swiotlb_alloc_tlb() can allocate from the DMA atomic pool when a decrypted
pool is needed from atomic context. With CONFIG_DMA_DIRECT_REMAP, the
atomic pool is backed by remapped virtual addresses, which are not the same
as the direct-map addresses returned by phys_to_virt().

swiotlb_init_io_tlb_pool() currently reconstructs the pool virtual address
from the physical start address. For atomic-pool backed allocations this
stores the wrong address in pool->vaddr. Later, swiotlb_free_tlb() passes
that address to dma_free_from_pool(), which will fail to recognize the
chunk

Pass the virtual address returned by the allocation path into
swiotlb_init_io_tlb_pool(), and store that address in pool->vaddr. This
keeps the pool free path using the same virtual address as the allocator.

Fixes: 79636caad3 ("swiotlb: if swiotlb is full, fall back to a transient memory pool")
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Petr Tesarik <ptesarik@suse.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20260717180442.110954-6-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

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Aneesh Kumar K.V (Arm) 2026-07-17 23:34:23 +05:30 • committed by Marek Szyprowski

parent 8a9dc4a028

commit 57d29044d0

1 changed files with 19 additions and 12 deletions

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kernel/dma/swiotlb.c

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