vfio: Use get_user_pages_longterm correctly

The patch noted in the fixes below converted get_user_pages_fast() to
get_user_pages_longterm(), however the two calls differ in a few ways.

First _fast() is documented to not require the mmap_sem, while _longterm()
is documented to need it. Hold the mmap sem as required.

Second, _fast accepts an 'int write' while _longterm uses 'unsigned int
gup_flags', so the expression '!!(prot & IOMMU_WRITE)' is only working by
luck as FOLL_WRITE is currently == 0x1. Use the expected FOLL_WRITE
constant instead.

Fixes: 94db151dc892 ("vfio: disable filesystem-dax page pinning")
Cc: <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Acked-by: Dan Williams <[email protected]>
Signed-off-by: Alex Williamson <[email protected]>

0 files changed, 0 insertions, 0 deletions