For the !HAVE_ATOMIC_IOMAP case the stub functions did not call pagefault_disable/_enable. The i915 driver relies on the map actually being atomic, otherwise it can deadlock with it's own pagefault handler in the gtt pwrite fastpath.

This is exercised by gem_mmap_gtt from the intel-gpu-toosl gem testsuite.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38115 Cc: stable@kernel.org Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- include/linux/io-mapping.h | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h index 8cdcc2a1..6b3bef1 100644 --- a/include/linux/io-mapping.h +++ b/include/linux/io-mapping.h @@ -138,12 +138,14 @@ static inline void __iomem * io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) { + pagefault_disable(); return ((char __force __iomem *) mapping) + offset; }

static inline void io_mapping_unmap_atomic(void __iomem *vaddr) { + pagefault_enable(); }

/* Non-atomic map/unmap */