Re: [PATCH UPSTREAM] xen-swiotlb: fix the check condition for xen_swiotlb_free_coherent

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, May 17, 2018 at 11:45:57AM -0700, Joe Jin wrote:
> When run raidconfig from Dom0 we found that the Xen DMA heap is reduced,
> but Dom Heap is increased by the same size. Tracing raidconfig we found
> that the related ioctl() in megaraid_sas will call dma_alloc_coherent()
> to apply memory. If the memory allocated by Dom0 is not in the DMA area,
> it will exchange memory with Xen to meet the requiment. Later drivers
> call dma_free_coherent() to free the memory, on xen_swiotlb_free_coherent()
> the check condition (dev_addr + size - 1 <= dma_mask) is always false,
> it prevents calling xen_destroy_contiguous_region() to return the memory
> to the Xen DMA heap.
> 
> This issue introduced by commit 6810df88dcfc2 "xen-swiotlb: When doing
> coherent alloc/dealloc check before swizzling the MFNs.".
> 
> Signed-off-by: Joe Jin <joe.jin@oracle.com>
> Tested-by: John Sobecki <john.sobecki@oracle.com> 
> Reviewed-by: Rzeszutek Wilk <konrad.wilk@oracle.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/xen/swiotlb-xen.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

What does "PATCH UPSTREAM" mean?

confused,

greg k-h