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author | Jiri Slaby <jslaby@suse.cz> | 2021-05-05 12:19:06 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-13 17:57:16 +0300 |
commit | 64d608db38ffc0c7a25455387096e0aad9410397 (patch) | |
tree | 356a8ff491e272f0d497c9da4401c7f0827c425d /drivers/tty/tty_io.c | |
parent | 6e94dbc7a4e49a028b81302d755bba1a518f973b (diff) | |
download | linux-64d608db38ffc0c7a25455387096e0aad9410397.tar.xz |
tty: cumulate and document tty_struct::ctrl* members
Group the ctrl members under a single struct called ctrl. The new struct
contains 'pgrp', 'session', 'pktstatus', and 'packet'. 'pktstatus' and
'packet' used to be bits in a bitfield. The struct also contains the
lock protecting them to share the same cache line.
Note that commit c545b66c6922b (tty: Serialize tcflow() with other tty
flow control changes) added a padding to the original bitfield. It was
for the bitfield to occupy a whole 64b word to avoid interferring stores
on Alpha (cannot we evaporate this arch with weird implications to C
code yet?). But it doesn't work as expected as the padding
(tty_struct::ctrl_unused) is aligned to a 8B boundary too and occupies
some bytes from the next word.
So make it reliable by:
1) setting __aligned of the struct -- that aligns the start, and
2) making 'unsigned long unused[0]' as the last member of the struct --
pads the end.
Add a kerneldoc comment for this grouped members.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20210505091928.22010-14-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r-- | drivers/tty/tty_io.c | 44 |
1 files changed, 22 insertions, 22 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 9734be2eb00e..362845dc1c19 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -638,15 +638,15 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) tty_ldisc_hangup(tty, cons_filp != NULL); - spin_lock_irq(&tty->ctrl_lock); + spin_lock_irq(&tty->ctrl.lock); clear_bit(TTY_THROTTLED, &tty->flags); clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); - put_pid(tty->session); - put_pid(tty->pgrp); - tty->session = NULL; - tty->pgrp = NULL; - tty->ctrl_status = 0; - spin_unlock_irq(&tty->ctrl_lock); + put_pid(tty->ctrl.session); + put_pid(tty->ctrl.pgrp); + tty->ctrl.session = NULL; + tty->ctrl.pgrp = NULL; + tty->ctrl.pktstatus = 0; + spin_unlock_irq(&tty->ctrl.lock); /* * If one of the devices matches a console pointer, we @@ -1559,8 +1559,8 @@ static void release_one_tty(struct work_struct *work) list_del_init(&tty->tty_files); spin_unlock(&tty->files_lock); - put_pid(tty->pgrp); - put_pid(tty->session); + put_pid(tty->ctrl.pgrp); + put_pid(tty->ctrl.session); free_tty_struct(tty); } @@ -1861,9 +1861,9 @@ int tty_release(struct inode *inode, struct file *filp) */ if (!tty->count) { read_lock(&tasklist_lock); - session_clear_tty(tty->session); + session_clear_tty(tty->ctrl.session); if (o_tty) - session_clear_tty(o_tty->session); + session_clear_tty(o_tty->ctrl.session); read_unlock(&tasklist_lock); } @@ -2250,16 +2250,16 @@ static int __tty_fasync(int fd, struct file *filp, int on) enum pid_type type; struct pid *pid; - spin_lock_irqsave(&tty->ctrl_lock, flags); - if (tty->pgrp) { - pid = tty->pgrp; + spin_lock_irqsave(&tty->ctrl.lock, flags); + if (tty->ctrl.pgrp) { + pid = tty->ctrl.pgrp; type = PIDTYPE_PGID; } else { pid = task_pid(current); type = PIDTYPE_TGID; } get_pid(pid); - spin_unlock_irqrestore(&tty->ctrl_lock, flags); + spin_unlock_irqrestore(&tty->ctrl.lock, flags); __f_setown(filp, pid, type, 0); put_pid(pid); retval = 0; @@ -2381,7 +2381,7 @@ EXPORT_SYMBOL(tty_do_resize); * * Locking: * Driver dependent. The default do_resize method takes the - * tty termios mutex and ctrl_lock. The console takes its own lock + * tty termios mutex and ctrl.lock. The console takes its own lock * then calls into the default method. */ @@ -3039,9 +3039,9 @@ void __do_SAK(struct tty_struct *tty) if (!tty) return; - spin_lock_irqsave(&tty->ctrl_lock, flags); - session = get_pid(tty->session); - spin_unlock_irqrestore(&tty->ctrl_lock, flags); + spin_lock_irqsave(&tty->ctrl.lock, flags); + session = get_pid(tty->ctrl.session); + spin_unlock_irqrestore(&tty->ctrl.lock, flags); tty_ldisc_flush(tty); @@ -3129,8 +3129,8 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) kfree(tty); return NULL; } - tty->session = NULL; - tty->pgrp = NULL; + tty->ctrl.session = NULL; + tty->ctrl.pgrp = NULL; mutex_init(&tty->legacy_mutex); mutex_init(&tty->throttle_mutex); init_rwsem(&tty->termios_rwsem); @@ -3140,7 +3140,7 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) init_waitqueue_head(&tty->read_wait); INIT_WORK(&tty->hangup_work, do_tty_hangup); mutex_init(&tty->atomic_write_lock); - spin_lock_init(&tty->ctrl_lock); + spin_lock_init(&tty->ctrl.lock); spin_lock_init(&tty->flow.lock); spin_lock_init(&tty->files_lock); INIT_LIST_HEAD(&tty->tty_files); |