Commit b07bc234 authored by Joakim Zhang's avatar Joakim Zhang Committed by Christoph Hellwig
Browse files

dma-mapping: clear dev->dma_mem to NULL after freeing it 



Reproduced with below sequence:
dma_declare_coherent_memory()->dma_release_coherent_memory()
->dma_declare_coherent_memory()->"return -EBUSY" error

It will return -EBUSY from the dma_assign_coherent_memory()
in dma_declare_coherent_memory(), the reason is that dev->dma_mem
pointer has not been set to NULL after it's freed.

Fixes: cf65a0f6 ("dma-mapping: move all DMA mapping code to kernel/dma")
Signed-off-by: default avatarJoakim Zhang <joakim.zhang@cixtech.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 55c54386

kernel/dma/coherent.c

+3 −1
Original line number Diff line number Diff line
@@ -132,8 +132,10 @@ int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr, 


void dma_release_coherent_memory(struct device *dev)

{

	if (dev)

	if (dev) {

		_dma_release_coherent_memory(dev->dma_mem);

		dev->dma_mem = NULL;

	}

}



static void *__dma_alloc_from_coherent(struct device *dev,