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dma-coherent: report a failed reserved memory assignment

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rmem_dma_device_init() drops the return value of
dma_assign_coherent_memory() and always reports success. That call fails
with -EBUSY when the device already has a coherent pool, and the file
allows only "*one* such region of memory" per device.

of_reserved_mem_device_init_by_idx() reads the zero as success. It logs
"assigned reserved memory node" for a region that was not assigned and
records the pairing, so of_reserved_mem_device_release() later runs
rmem_dma_device_release() for it. That clears dev->dma_mem without
looking at which region it was called for, dropping the pool the device
did get and leaving it on ordinary memory.

dma_declare_coherent_memory() checks the same call and releases the
memory on failure, and rmem_swiotlb_device_init() propagates its own
errors. Return the error here as well, so a device tree that assigns two
pools to one device fails the probe instead of half working.

Fixes: 7bfa5ab6fa ("drivers: dma-coherent: add initialization from device tree")
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Link: https://lore.kernel.org/r/20260905074727.108029-1-donggeunyoo.kernel@gmail.com
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
This commit is contained in:
Donggeun Yoo 2026-09-05 16:47:27 +09:00 committed by Marek Szyprowski
parent cee9395acd
commit 504981db4f
1 changed files with 1 additions and 2 deletions
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3
kernel/dma/coherent.c
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@ -352,8 +352,7 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit))
dev_warn(dev, "reserved memory is beyond device's set DMA address range\n");
dma_assign_coherent_memory(dev, mem);
return 0;
return dma_assign_coherent_memory(dev, mem);
}
static void rmem_dma_device_release(struct reserved_mem *rmem,