sysfs: don't block indefinitely for unmapped files.

Modify sysfs bin files so that we can remove the bin file while they are
still mapped.  When the kobject is removed we unmap the bin file and
arrange for future accesses to the mapping to receive SIGBUS.

Implementing this prevents a nasty DOS when pci devices are hot plugged
and unplugged.  Where if any of their resources were mmaped the kernel
could not free up their pci resources or release their pci data
structures.

[[email protected]: remove unused var]
Signed-off-by: Eric W. Biederman <[email protected]>
Cc: Jesse Barnes <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Cc: Kay Sievers <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions