tree 52a33557d35040b48a943cbafa1eb64fd2ab6601
parent 1b9c86c9dc8399914650062f6183619b7ec30363
author Joe Jin <joe.jin@oracle.com> 1526585608 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1527659417 +0200

xen-swiotlb: fix the check condition for xen_swiotlb_free_coherent

commit 4855c92dbb7b3b85c23e88ab7ca04f99b9677b41 upstream.

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
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>