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io-mapping: ensure io_mapping_map_atomic _is_ atomic 

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.

v2: Chris Wilson noted the lack of an include.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38115
Cc: stable@kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>
hifive-unleashed-5.1
Daniel Vetter 2011-09-28 11:57:23 +02:00 committed by Keith Packard
parent 8ffc024681
commit 24dd85ff72
1 changed files with 4 additions and 0 deletions
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4
include/linux/io-mapping.h
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@ -117,6 +117,8 @@ io_mapping_unmap(void __iomem *vaddr)
#else
#include <linux/uaccess.h>
/* this struct isn't actually defined anywhere */
struct io_mapping;
@ -138,12 +140,14 @@ 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 */