]> git.baikalelectronics.ru Git - kernel.git/commit
tty: fix up atime/mtime mess, take three
authorLinus Torvalds <torvalds@linux-foundation.org>
Wed, 1 May 2013 14:32:21 +0000 (07:32 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 1 May 2013 14:32:21 +0000 (07:32 -0700)
commit9d12d733ae451d7a932aa087d85e93283b70e8e3
tree1d9569036a89ad458fdc25f67a20fbf56a7cf340
parentb8a3008b82de6e87e1a239d56cd946a7883f78a9
tty: fix up atime/mtime mess, take three

We first tried to avoid updating atime/mtime entirely (commit
8bfcd46ea914: "TTY: do not update atime/mtime on read/write"), and then
limited it to only update it occasionally (commit eca86a1c9fbe: "TTY:
fix atime/mtime regression"), but it turns out that this was both
insufficient and overkill.

It was insufficient because we let people attach to the shared ptmx node
to see activity without even reading atime/mtime, and it was overkill
because the "only once a minute" means that you can't really tell an
idle person from an active one with 'w'.

So this tries to fix the problem properly.  It marks the shared ptmx
node as un-notifiable, and it lowers the "only once a minute" to a few
seconds instead - still long enough that you can't time individual
keystrokes, but short enough that you can tell whether somebody is
active or not.

Reported-by: Simon Kirby <sim@hostway.ca>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/tty/pty.c
drivers/tty/tty_io.c