K 10
svn:author
V 3
jhb
K 8
svn:date
V 27
2016-01-20T00:14:34.649358Z
K 7
svn:log
V 617
Initialize vm_page_prot to VM_MEMATTR_DEFAULT instead of 0.

If a driver's Linux mmap callback passed vm_page_prot through unchanged,
then linux_dev_mmap_single() would try to apply whatever VM_MEMATTR_xxx
value 0 is to the mapping.  On x86, VM_MEMATTR_DEFAULT is the PAT value
for write-back (WB) which is 6, while 0 maps to the PAT value for
uncacheable (UC).  Thus, any mmap request that did not explicitly set
page_prot was tried to map memory as UC triggering the warning in
sg_pager_getpages().

Tested by:	np
Reported by:	Krishnamraju Eraparaju @ Chelsio
MFC after:	3 days
Sponsored by:	Chelsio Communications

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