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| author | Eric W. Biederman <ebiederm@xmission.com> | 2007-02-10 01:44:34 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-11 10:51:24 -0800 |
| commit | 8b6312f4dcc1efe7975731b6c47dd134282bd9ac (patch) | |
| tree | 71c94b01bda940c5610d448d0f4a2aa3c7665b4c /drivers/char/vt_ioctl.c | |
| parent | 0a7b35cb18c52d651f6ed9cd59edc979200ab880 (diff) | |
| download | linux-8b6312f4dcc1efe7975731b6c47dd134282bd9ac.tar.gz linux-8b6312f4dcc1efe7975731b6c47dd134282bd9ac.tar.bz2 linux-8b6312f4dcc1efe7975731b6c47dd134282bd9ac.zip | |
[PATCH] vt: refactor console SAK processing
This does several things.
- It moves looking up of the current foreground console into process
context where we can safely take the semaphore that protects this
operation.
- It uses the new flavor of work queue processing.
- This generates a factor of do_SAK, __do_SAK that runs immediately.
- This calls __do_SAK with the console semaphore held ensuring nothing
else happens to the console while we process the SAK operation.
- With the console SAK processing moved into process context this
patch removes the xchg operations that I used to attempt to attomically
update struct pid, because of the strange locking used in the SAK processing.
With SAK using the normal console semaphore nothing special is needed.
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char/vt_ioctl.c')
| -rw-r--r-- | drivers/char/vt_ioctl.c | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c index dc8368ebb1ac..3a5d301e783b 100644 --- a/drivers/char/vt_ioctl.c +++ b/drivers/char/vt_ioctl.c @@ -672,7 +672,8 @@ int vt_ioctl(struct tty_struct *tty, struct file * file, vc->vt_mode = tmp; /* the frsig is ignored, so we set it to 0 */ vc->vt_mode.frsig = 0; - put_pid(xchg(&vc->vt_pid, get_pid(task_pid(current)))); + put_pid(vc->vt_pid); + vc->vt_pid = get_pid(task_pid(current)); /* no switch is required -- saw@shade.msu.ru */ vc->vt_newvt = -1; release_console_sem(); @@ -1063,12 +1064,35 @@ void reset_vc(struct vc_data *vc) vc->vt_mode.relsig = 0; vc->vt_mode.acqsig = 0; vc->vt_mode.frsig = 0; - put_pid(xchg(&vc->vt_pid, NULL)); + put_pid(vc->vt_pid); + vc->vt_pid = NULL; vc->vt_newvt = -1; if (!in_interrupt()) /* Via keyboard.c:SAK() - akpm */ reset_palette(vc); } +void vc_SAK(struct work_struct *work) +{ + struct vc *vc_con = + container_of(work, struct vc, SAK_work); + struct vc_data *vc; + struct tty_struct *tty; + + acquire_console_sem(); + vc = vc_con->d; + if (vc) { + tty = vc->vc_tty; + /* + * SAK should also work in all raw modes and reset + * them properly. + */ + if (tty) + __do_SAK(tty); + reset_vc(vc); + } + release_console_sem(); +} + /* * Performs the back end of a vt switch */ |