Message ID | 20240415152617552rmRLJBUV8aJ4lLJILh6-Z@zte.com.cn (mailing list archive) |
---|---|
State | Handled Elsewhere |
Headers | show |
Series | [v2] tty: hvc: wakeup hvc console immediately when needed | expand |
Context | Check | Description |
---|---|---|
snowpatch_ozlabs/github-powerpc_sparse | success | Successfully ran 4 jobs. |
snowpatch_ozlabs/github-powerpc_clang | success | Successfully ran 6 jobs. |
snowpatch_ozlabs/github-powerpc_kernel_qemu | success | Successfully ran 23 jobs. |
On Mon, Apr 15, 2024 at 03:26:17PM +0800, li.hao40@zte.com.cn wrote: > From: Li Hao <li.hao40@zte.com.cn> > > Cancel the do_wakeup flag in hvc_struct, and change it to immediately > wake up tty when hp->n_outbuf is 0 in hvc_push(). > > When we receive a key input character, the interrupt handling function > hvc_handle_interrupt() will be executed, and the echo thread > flush_to_ldisc() will be added to the queue. > > If the user is currently using tcsetattr(), a hang may occur. tcsetattr() > enters kernel and waits for hp->n_outbuf to become 0 via > tty_wait_until_sent(). If the echo thread finishes executing before > reaching tty_wait_until_sent (for example, put_chars() takes too long), > it will cause while meeting the wakeup condition (hp->do_wakeup = 1), > tty_wait_until_sent() cannot be woken up (missed the tty_wakeup() of > this round's tty_poll). Unless the next key input character comes, > hvc_poll will be executed, and tty_wakeup() will be performed through > the do_wakeup flag. > > v1->v2: > Some fixes according to: > https://lore.kernel.org/all/75dff5cd-7b0e-4039-9157-8bf10cf7ba29@kernel.org/ > use tty_port_tty_wakeup() instead of tty_wakeup() to wake up tty As per the documentation, the v1... stuff needs to go below the --- line so git will strip it away. Please fix up and send a v3. thanks, greg k-h
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c index cd1f657f7..cbd234847 100644 --- a/drivers/tty/hvc/hvc_console.c +++ b/drivers/tty/hvc/hvc_console.c @@ -480,7 +480,7 @@ static int hvc_push(struct hvc_struct *hp) n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); if (n <= 0) { if (n == 0 || n == -EAGAIN) { - hp->do_wakeup = 1; + tty_port_tty_wakeup(&hp->port); return 0; } /* throw away output on error; this happens when @@ -491,7 +491,7 @@ static int hvc_push(struct hvc_struct *hp) if (hp->n_outbuf > 0) memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); else - hp->do_wakeup = 1; + tty_port_tty_wakeup(&hp->port); return n; } @@ -739,11 +739,7 @@ static int __hvc_poll(struct hvc_struct *hp, bool may_sleep) poll_mask |= HVC_POLL_READ; out: - /* Wakeup write queue if necessary */ - if (hp->do_wakeup) { - hp->do_wakeup = 0; - tty_wakeup(tty); - } + /* Wakeup in hvc_push */ bail: spin_unlock_irqrestore(&hp->lock, flags); diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h index cf4c1af08..6622f71ba 100644 --- a/drivers/tty/hvc/hvc_console.h +++ b/drivers/tty/hvc/hvc_console.h @@ -36,7 +36,6 @@ struct hvc_struct { struct tty_port port; spinlock_t lock; int index; - int do_wakeup; int outbuf_size; int n_outbuf; uint32_t vtermno;