| commit | bafb0bd24d7e0e0124318625b239a55d58c757a2 | |
| author | Jiri Slaby <jslaby@suse.cz> | |
| Thu, 25 Aug 2011 13:12:05 +0000 (25 15:12 +0200) | ||
| committer | Greg Kroah-Hartman <gregkh@suse.de> | |
| Thu, 25 Aug 2011 16:00:39 +0000 (25 09:00 -0700) | ||
| tree | c5e262faa274ed54696cfb433717b99ddcee966c | treesnapshot (tar.gz zip) |
| parent | 426929f8d3514d7f727b8c464d1eeeaf74b21519 | commitdiff |
TTY: serial, move locking in uart_close
So now, when we handle CLOSING flag, there is no point to hold
port->mutex over the start of uart_close.
Yes, there are still several things to reason about:
* port->count etc is and always was protected by a spinlock
* ->stop_rx is protected by a spinlock. Otherwise it would
race with interrupts.
* uart_wait_until_sent -- that one is already called without
port->mutex from set_termios and tty_set_ldisc. Should anything
be protected there, it would be tx_empty. And by a spinlock.
8250 does this internally...
This step is needed to fix system stalls. To not create an AB-BA lock
dependency (see next patches).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
So now, when we handle CLOSING flag, there is no point to hold
port->mutex over the start of uart_close.
Yes, there are still several things to reason about:
* port->count etc is and always was protected by a spinlock
* ->stop_rx is protected by a spinlock. Otherwise it would
race with interrupts.
* uart_wait_until_sent -- that one is already called without
port->mutex from set_termios and tty_set_ldisc. Should anything
be protected there, it would be tx_empty. And by a spinlock.
8250 does this internally...
This step is needed to fix system stalls. To not create an AB-BA lock
dependency (see next patches).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| drivers/tty/serial/serial_core.c | diffblobblamehistory |