K 10
svn:author
V 3
kib
K 8
svn:date
V 27
2008-09-26T14:50:49.594392Z
K 7
svn:log
V 543
Save previous content of the td_fpop before storing the current
filedescriptor into it. Make sure that td_fpop is NULL when calling
d_mmap from dev_pager_getpages().

Change guards against td_fpop field being non-NULL with private state
for another device, and against sudden clearing the td_fpop. This
could occur when either a driver method calls another driver through
the filedescriptor operation, or a page fault happen while driver is
writing to a memory backed by another driver.

Noted by:	rwatson
Tested by:	rnoland
MFC after:	3 days

END