diff options
author | Dave Kleikamp <shaggy@austin.ibm.com> | 2006-03-14 17:05:45 -0600 |
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committer | Dave Kleikamp <shaggy@austin.ibm.com> | 2006-03-14 17:05:45 -0600 |
commit | c5111f504d2a9b0d258d7c4752b4093523315989 (patch) | |
tree | 6a52864aff79691689aea21cb0cb928327d5de5b /drivers/char/tty_io.c | |
parent | 69eb66d7da7dba2696281981347698e1693c2340 (diff) | |
parent | a488edc914aa1d766a4e2c982b5ae03d5657ec1b (diff) |
Merge with /home/shaggy/git/linus-clean/
Diffstat (limited to 'drivers/char/tty_io.c')
-rw-r--r-- | drivers/char/tty_io.c | 106 |
1 files changed, 71 insertions, 35 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index eb8b5be4e24..53d3d066554 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -253,6 +253,7 @@ static void tty_buffer_free_all(struct tty_struct *tty) static void tty_buffer_init(struct tty_struct *tty) { + spin_lock_init(&tty->buf.lock); tty->buf.head = NULL; tty->buf.tail = NULL; tty->buf.free = NULL; @@ -266,6 +267,9 @@ static struct tty_buffer *tty_buffer_alloc(size_t size) p->used = 0; p->size = size; p->next = NULL; + p->active = 0; + p->commit = 0; + p->read = 0; p->char_buf_ptr = (char *)(p->data); p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; /* printk("Flip create %p\n", p); */ @@ -296,8 +300,10 @@ static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) *tbh = t->next; t->next = NULL; t->used = 0; + t->commit = 0; + t->read = 0; /* DEBUG ONLY */ - memset(t->data, '*', size); +/* memset(t->data, '*', size); */ /* printk("Flip recycle %p\n", t); */ return t; } @@ -312,25 +318,37 @@ static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) int tty_buffer_request_room(struct tty_struct *tty, size_t size) { - struct tty_buffer *b = tty->buf.tail, *n; - int left = 0; + struct tty_buffer *b, *n; + int left; + unsigned long flags; + + spin_lock_irqsave(&tty->buf.lock, flags); /* OPTIMISATION: We could keep a per tty "zero" sized buffer to remove this conditional if its worth it. This would be invisible to the callers */ - if(b != NULL) + if ((b = tty->buf.tail) != NULL) { left = b->size - b->used; - if(left >= size) - return size; - /* This is the slow path - looking for new buffers to use */ - n = tty_buffer_find(tty, size); - if(n == NULL) - return left; - if(b != NULL) - b->next = n; - else - tty->buf.head = n; - tty->buf.tail = n; + b->active = 1; + } else + left = 0; + + if (left < size) { + /* This is the slow path - looking for new buffers to use */ + if ((n = tty_buffer_find(tty, size)) != NULL) { + if (b != NULL) { + b->next = n; + b->active = 0; + b->commit = b->used; + } else + tty->buf.head = n; + tty->buf.tail = n; + n->active = 1; + } else + size = left; + } + + spin_unlock_irqrestore(&tty->buf.lock, flags); return size; } @@ -396,10 +414,12 @@ EXPORT_SYMBOL_GPL(tty_insert_flip_string_flags); int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size) { int space = tty_buffer_request_room(tty, size); - struct tty_buffer *tb = tty->buf.tail; - *chars = tb->char_buf_ptr + tb->used; - memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); - tb->used += space; + if (likely(space)) { + struct tty_buffer *tb = tty->buf.tail; + *chars = tb->char_buf_ptr + tb->used; + memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); + tb->used += space; + } return space; } @@ -416,10 +436,12 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string); int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size) { int space = tty_buffer_request_room(tty, size); - struct tty_buffer *tb = tty->buf.tail; - *chars = tb->char_buf_ptr + tb->used; - *flags = tb->flag_buf_ptr + tb->used; - tb->used += space; + if (likely(space)) { + struct tty_buffer *tb = tty->buf.tail; + *chars = tb->char_buf_ptr + tb->used; + *flags = tb->flag_buf_ptr + tb->used; + tb->used += space; + } return space; } @@ -1819,7 +1841,6 @@ static void release_dev(struct file * filp) tty_closing = tty->count <= 1; o_tty_closing = o_tty && (o_tty->count <= (pty_master ? 1 : 0)); - up(&tty_sem); do_sleep = 0; if (tty_closing) { @@ -1847,6 +1868,7 @@ static void release_dev(struct file * filp) printk(KERN_WARNING "release_dev: %s: read/write wait queue " "active!\n", tty_name(tty, buf)); + up(&tty_sem); schedule(); } @@ -1855,8 +1877,6 @@ static void release_dev(struct file * filp) * both sides, and we've completed the last operation that could * block, so it's safe to proceed with closing. */ - - down(&tty_sem); if (pty_master) { if (--o_tty->count < 0) { printk(KERN_WARNING "release_dev: bad pty slave count " @@ -1870,7 +1890,6 @@ static void release_dev(struct file * filp) tty->count, tty_name(tty, buf)); tty->count = 0; } - up(&tty_sem); /* * We've decremented tty->count, so we need to remove this file @@ -1915,6 +1934,8 @@ static void release_dev(struct file * filp) read_unlock(&tasklist_lock); } + up(&tty_sem); + /* check whether both sides are closing ... */ if (!tty_closing || (o_tty && !o_tty_closing)) return; @@ -2735,6 +2756,9 @@ static void flush_to_ldisc(void *private_) unsigned long flags; struct tty_ldisc *disc; struct tty_buffer *tbuf; + int count; + char *char_buf; + unsigned char *flag_buf; disc = tty_ldisc_ref(tty); if (disc == NULL) /* !TTY_LDISC */ @@ -2747,20 +2771,24 @@ static void flush_to_ldisc(void *private_) schedule_delayed_work(&tty->buf.work, 1); goto out; } - spin_lock_irqsave(&tty->read_lock, flags); + spin_lock_irqsave(&tty->buf.lock, flags); while((tbuf = tty->buf.head) != NULL) { + while ((count = tbuf->commit - tbuf->read) != 0) { + char_buf = tbuf->char_buf_ptr + tbuf->read; + flag_buf = tbuf->flag_buf_ptr + tbuf->read; + tbuf->read += count; + spin_unlock_irqrestore(&tty->buf.lock, flags); + disc->receive_buf(tty, char_buf, flag_buf, count); + spin_lock_irqsave(&tty->buf.lock, flags); + } + if (tbuf->active) + break; tty->buf.head = tbuf->next; if (tty->buf.head == NULL) tty->buf.tail = NULL; - spin_unlock_irqrestore(&tty->read_lock, flags); - /* printk("Process buffer %p for %d\n", tbuf, tbuf->used); */ - disc->receive_buf(tty, tbuf->char_buf_ptr, - tbuf->flag_buf_ptr, - tbuf->used); - spin_lock_irqsave(&tty->read_lock, flags); tty_buffer_free(tty, tbuf); } - spin_unlock_irqrestore(&tty->read_lock, flags); + spin_unlock_irqrestore(&tty->buf.lock, flags); out: tty_ldisc_deref(disc); } @@ -2852,6 +2880,14 @@ EXPORT_SYMBOL(tty_get_baud_rate); void tty_flip_buffer_push(struct tty_struct *tty) { + unsigned long flags; + spin_lock_irqsave(&tty->buf.lock, flags); + if (tty->buf.tail != NULL) { + tty->buf.tail->active = 0; + tty->buf.tail->commit = tty->buf.tail->used; + } + spin_unlock_irqrestore(&tty->buf.lock, flags); + if (tty->low_latency) flush_to_ldisc((void *) tty); else |