Merge branch 'topic/hvc' into next
This branch held some hvc related commits (Hypervisor Virtual Console) so that they could get some wider testing in linux-next before merging.
This commit is contained in:
Michael Ellerman
Коммит
70b5c4ee8e
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@ -73,7 +73,7 @@ static LIST_HEAD(hvc_structs);
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* Protect the list of hvc_struct instances from inserts and removals during
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* list traversal.
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*/
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static DEFINE_SPINLOCK(hvc_structs_lock);
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static DEFINE_MUTEX(hvc_structs_mutex);
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/*
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* This value is used to assign a tty->index value to a hvc_struct based
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@ -83,7 +83,7 @@ static DEFINE_SPINLOCK(hvc_structs_lock);
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static int last_hvc = -1;
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/*
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* Do not call this function with either the hvc_structs_lock or the hvc_struct
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* Do not call this function with either the hvc_structs_mutex or the hvc_struct
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* lock held. If successful, this function increments the kref reference
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* count against the target hvc_struct so it should be released when finished.
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*/
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@ -92,24 +92,46 @@ static struct hvc_struct *hvc_get_by_index(int index)
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struct hvc_struct *hp;
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unsigned long flags;
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spin_lock(&hvc_structs_lock);
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mutex_lock(&hvc_structs_mutex);
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list_for_each_entry(hp, &hvc_structs, next) {
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spin_lock_irqsave(&hp->lock, flags);
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if (hp->index == index) {
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tty_port_get(&hp->port);
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spin_unlock_irqrestore(&hp->lock, flags);
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spin_unlock(&hvc_structs_lock);
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mutex_unlock(&hvc_structs_mutex);
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return hp;
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}
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spin_unlock_irqrestore(&hp->lock, flags);
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}
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hp = NULL;
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mutex_unlock(&hvc_structs_mutex);
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spin_unlock(&hvc_structs_lock);
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return hp;
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}
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static int __hvc_flush(const struct hv_ops *ops, uint32_t vtermno, bool wait)
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{
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if (wait)
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might_sleep();
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if (ops->flush)
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return ops->flush(vtermno, wait);
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return 0;
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}
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static int hvc_console_flush(const struct hv_ops *ops, uint32_t vtermno)
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{
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return __hvc_flush(ops, vtermno, false);
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}
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/*
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* Wait for the console to flush before writing more to it. This sleeps.
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*/
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static int hvc_flush(struct hvc_struct *hp)
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{
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return __hvc_flush(hp->ops, hp->vtermno, true);
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}
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/*
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* Initial console vtermnos for console API usage prior to full console
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@ -156,8 +178,12 @@ static void hvc_console_print(struct console *co, const char *b,
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if (r <= 0) {
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/* throw away characters on error
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* but spin in case of -EAGAIN */
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if (r != -EAGAIN)
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if (r != -EAGAIN) {
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i = 0;
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} else {
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hvc_console_flush(cons_ops[index],
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vtermnos[index]);
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}
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} else if (r > 0) {
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i -= r;
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if (i > 0)
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@ -165,6 +191,7 @@ static void hvc_console_print(struct console *co, const char *b,
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}
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}
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}
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hvc_console_flush(cons_ops[index], vtermnos[index]);
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}
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static struct tty_driver *hvc_console_device(struct console *c, int *index)
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@ -224,13 +251,13 @@ static void hvc_port_destruct(struct tty_port *port)
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struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
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unsigned long flags;
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spin_lock(&hvc_structs_lock);
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mutex_lock(&hvc_structs_mutex);
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spin_lock_irqsave(&hp->lock, flags);
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list_del(&(hp->next));
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spin_unlock_irqrestore(&hp->lock, flags);
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spin_unlock(&hvc_structs_lock);
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mutex_unlock(&hvc_structs_mutex);
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kfree(hp);
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}
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@ -494,13 +521,12 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
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if (hp->port.count <= 0)
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return -EIO;
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while (count > 0) {
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spin_lock_irqsave(&hp->lock, flags);
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/* Push pending writes */
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if (hp->n_outbuf > 0)
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hvc_push(hp);
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rsize = hp->outbuf_size - hp->n_outbuf;
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while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
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if (rsize) {
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if (rsize > count)
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rsize = count;
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memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
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@ -508,10 +534,20 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
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buf += rsize;
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hp->n_outbuf += rsize;
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written += rsize;
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hvc_push(hp);
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}
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if (hp->n_outbuf > 0)
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hvc_push(hp);
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spin_unlock_irqrestore(&hp->lock, flags);
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if (count) {
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if (hp->n_outbuf > 0)
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hvc_flush(hp);
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cond_resched();
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}
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}
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/*
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* Racy, but harmless, kick thread if there is still pending data.
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*/
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@ -590,10 +626,10 @@ static u32 timeout = MIN_TIMEOUT;
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#define HVC_POLL_READ 0x00000001
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#define HVC_POLL_WRITE 0x00000002
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int hvc_poll(struct hvc_struct *hp)
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static int __hvc_poll(struct hvc_struct *hp, bool may_sleep)
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{
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struct tty_struct *tty;
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int i, n, poll_mask = 0;
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int i, n, count, poll_mask = 0;
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char buf[N_INBUF] __ALIGNED__;
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unsigned long flags;
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int read_total = 0;
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@ -612,6 +648,12 @@ int hvc_poll(struct hvc_struct *hp)
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timeout = (written_total) ? 0 : MIN_TIMEOUT;
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}
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if (may_sleep) {
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spin_unlock_irqrestore(&hp->lock, flags);
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cond_resched();
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spin_lock_irqsave(&hp->lock, flags);
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}
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/* No tty attached, just skip */
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tty = tty_port_tty_get(&hp->port);
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if (tty == NULL)
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@ -619,7 +661,7 @@ int hvc_poll(struct hvc_struct *hp)
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/* Now check if we can get data (are we throttled ?) */
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if (tty_throttled(tty))
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goto throttled;
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goto out;
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/* If we aren't notifier driven and aren't throttled, we always
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* request a reschedule
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@ -628,13 +670,13 @@ int hvc_poll(struct hvc_struct *hp)
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poll_mask |= HVC_POLL_READ;
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/* Read data if any */
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for (;;) {
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int count = tty_buffer_request_room(&hp->port, N_INBUF);
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count = tty_buffer_request_room(&hp->port, N_INBUF);
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/* If flip is full, just reschedule a later read */
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if (count == 0) {
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poll_mask |= HVC_POLL_READ;
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break;
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goto out;
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}
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n = hp->ops->get_chars(hp->vtermno, buf, count);
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@ -652,8 +694,9 @@ int hvc_poll(struct hvc_struct *hp)
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*/
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poll_mask |= HVC_POLL_READ;
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}
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break;
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goto out;
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}
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for (i = 0; i < n; ++i) {
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#ifdef CONFIG_MAGIC_SYSRQ
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if (hp->index == hvc_console.index) {
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@ -674,10 +717,11 @@ int hvc_poll(struct hvc_struct *hp)
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#endif /* CONFIG_MAGIC_SYSRQ */
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tty_insert_flip_char(&hp->port, buf[i], 0);
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}
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if (n == count)
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poll_mask |= HVC_POLL_READ;
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read_total = n;
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read_total += n;
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}
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throttled:
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out:
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/* Wakeup write queue if necessary */
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if (hp->do_wakeup) {
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hp->do_wakeup = 0;
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@ -697,6 +741,11 @@ int hvc_poll(struct hvc_struct *hp)
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return poll_mask;
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}
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int hvc_poll(struct hvc_struct *hp)
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{
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return __hvc_poll(hp, false);
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}
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EXPORT_SYMBOL_GPL(hvc_poll);
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/**
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@ -733,11 +782,12 @@ static int khvcd(void *unused)
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try_to_freeze();
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wmb();
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if (!cpus_are_in_xmon()) {
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spin_lock(&hvc_structs_lock);
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mutex_lock(&hvc_structs_mutex);
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list_for_each_entry(hp, &hvc_structs, next) {
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poll_mask |= hvc_poll(hp);
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poll_mask |= __hvc_poll(hp, true);
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cond_resched();
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}
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spin_unlock(&hvc_structs_lock);
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mutex_unlock(&hvc_structs_mutex);
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} else
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poll_mask |= HVC_POLL_READ;
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if (hvc_kicked)
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@ -871,7 +921,7 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
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INIT_WORK(&hp->tty_resize, hvc_set_winsz);
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spin_lock_init(&hp->lock);
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spin_lock(&hvc_structs_lock);
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mutex_lock(&hvc_structs_mutex);
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/*
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* find index to use:
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@ -891,7 +941,7 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
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vtermnos[i] = vtermno;
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list_add_tail(&(hp->next), &hvc_structs);
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spin_unlock(&hvc_structs_lock);
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mutex_unlock(&hvc_structs_mutex);
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/* check if we need to re-register the kernel console */
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hvc_check_console(i);
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@ -54,6 +54,7 @@ struct hvc_struct {
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struct hv_ops {
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int (*get_chars)(uint32_t vtermno, char *buf, int count);
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int (*put_chars)(uint32_t vtermno, const char *buf, int count);
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int (*flush)(uint32_t vtermno, bool wait);
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/* Callbacks for notification. Called in open, close and hangup */
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int (*notifier_add)(struct hvc_struct *hp, int irq);
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