X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=drivers%2Fchar%2Ftty_io.c;h=eb8b5be4e2494c318e9f4af4195d8cd0b63cede7;hb=b4290a23cfa9040e2f0de5ab57d6ea65abaf053b;hp=4b1eef51ec5926d97918331f20740c3664067375;hpb=8f0cb147b2fb12427bf6abef7fed2b604557a41e;p=powerpc.git diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 4b1eef51ec..eb8b5be4e2 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -166,9 +166,12 @@ static struct tty_struct *alloc_tty_struct(void) return tty; } +static void tty_buffer_free_all(struct tty_struct *); + static inline void free_tty_struct(struct tty_struct *tty) { kfree(tty->write_buf); + tty_buffer_free_all(tty); kfree(tty); } @@ -230,6 +233,200 @@ static int check_tty_count(struct tty_struct *tty, const char *routine) return 0; } +/* + * Tty buffer allocation management + */ + +static void tty_buffer_free_all(struct tty_struct *tty) +{ + struct tty_buffer *thead; + while((thead = tty->buf.head) != NULL) { + tty->buf.head = thead->next; + kfree(thead); + } + while((thead = tty->buf.free) != NULL) { + tty->buf.free = thead->next; + kfree(thead); + } + tty->buf.tail = NULL; +} + +static void tty_buffer_init(struct tty_struct *tty) +{ + tty->buf.head = NULL; + tty->buf.tail = NULL; + tty->buf.free = NULL; +} + +static struct tty_buffer *tty_buffer_alloc(size_t size) +{ + struct tty_buffer *p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); + if(p == NULL) + return NULL; + p->used = 0; + p->size = size; + p->next = NULL; + p->char_buf_ptr = (char *)(p->data); + p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; +/* printk("Flip create %p\n", p); */ + return p; +} + +/* Must be called with the tty_read lock held. This needs to acquire strategy + code to decide if we should kfree or relink a given expired buffer */ + +static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) +{ + /* Dumb strategy for now - should keep some stats */ +/* printk("Flip dispose %p\n", b); */ + if(b->size >= 512) + kfree(b); + else { + b->next = tty->buf.free; + tty->buf.free = b; + } +} + +static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) +{ + struct tty_buffer **tbh = &tty->buf.free; + while((*tbh) != NULL) { + struct tty_buffer *t = *tbh; + if(t->size >= size) { + *tbh = t->next; + t->next = NULL; + t->used = 0; + /* DEBUG ONLY */ + memset(t->data, '*', size); +/* printk("Flip recycle %p\n", t); */ + return t; + } + tbh = &((*tbh)->next); + } + /* Round the buffer size out */ + size = (size + 0xFF) & ~ 0xFF; + return tty_buffer_alloc(size); + /* Should possibly check if this fails for the largest buffer we + have queued and recycle that ? */ +} + +int tty_buffer_request_room(struct tty_struct *tty, size_t size) +{ + struct tty_buffer *b = tty->buf.tail, *n; + int left = 0; + + /* 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) + 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; + return size; +} + +EXPORT_SYMBOL_GPL(tty_buffer_request_room); + +int tty_insert_flip_string(struct tty_struct *tty, unsigned char *chars, size_t size) +{ + int copied = 0; + do { + int space = tty_buffer_request_room(tty, size - copied); + struct tty_buffer *tb = tty->buf.tail; + /* If there is no space then tb may be NULL */ + if(unlikely(space == 0)) + break; + memcpy(tb->char_buf_ptr + tb->used, chars, space); + memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); + tb->used += space; + copied += space; + chars += space; +/* printk("Flip insert %d.\n", space); */ + } + /* There is a small chance that we need to split the data over + several buffers. If this is the case we must loop */ + while (unlikely(size > copied)); + return copied; +} + +EXPORT_SYMBOL_GPL(tty_insert_flip_string); + +int tty_insert_flip_string_flags(struct tty_struct *tty, unsigned char *chars, char *flags, size_t size) +{ + int copied = 0; + do { + int space = tty_buffer_request_room(tty, size - copied); + struct tty_buffer *tb = tty->buf.tail; + /* If there is no space then tb may be NULL */ + if(unlikely(space == 0)) + break; + memcpy(tb->char_buf_ptr + tb->used, chars, space); + memcpy(tb->flag_buf_ptr + tb->used, flags, space); + tb->used += space; + copied += space; + chars += space; + flags += space; + } + /* There is a small chance that we need to split the data over + several buffers. If this is the case we must loop */ + while (unlikely(size > copied)); + return copied; +} + +EXPORT_SYMBOL_GPL(tty_insert_flip_string_flags); + + +/* + * Prepare a block of space in the buffer for data. Returns the length + * available and buffer pointer to the space which is now allocated and + * accounted for as ready for normal characters. This is used for drivers + * that need their own block copy routines into the buffer. There is no + * guarantee the buffer is a DMA target! + */ + +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; + return space; +} + +EXPORT_SYMBOL_GPL(tty_prepare_flip_string); + +/* + * Prepare a block of space in the buffer for data. Returns the length + * available and buffer pointer to the space which is now allocated and + * accounted for as ready for characters. This is used for drivers + * that need their own block copy routines into the buffer. There is no + * guarantee the buffer is a DMA target! + */ + +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; + return space; +} + +EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); + + + /* * This is probably overkill for real world processors but * they are not on hot paths so a little discipline won't do @@ -492,6 +689,17 @@ restart: if (ld == NULL) return -EINVAL; + /* + * No more input please, we are switching. The new ldisc + * will update this value in the ldisc open function + */ + + tty->receive_room = 0; + + /* + * Problem: What do we do if this blocks ? + */ + tty_wait_until_sent(tty, 0); if (tty->ldisc.num == ldisc) { @@ -560,9 +768,9 @@ restart: * we say so later on. */ - work = cancel_delayed_work(&tty->flip.work); + work = cancel_delayed_work(&tty->buf.work); /* - * Wait for ->hangup_work and ->flip.work handlers to terminate + * Wait for ->hangup_work and ->buf.work handlers to terminate */ flush_scheduled_work(); @@ -616,7 +824,7 @@ restart: /* Restart it in case no characters kick it off. Safe if already running */ if (work) - schedule_delayed_work(&tty->flip.work, 1); + schedule_delayed_work(&tty->buf.work, 1); return retval; } @@ -1721,10 +1929,10 @@ static void release_dev(struct file * filp) */ clear_bit(TTY_LDISC, &tty->flags); clear_bit(TTY_DONT_FLIP, &tty->flags); - cancel_delayed_work(&tty->flip.work); + cancel_delayed_work(&tty->buf.work); /* - * Wait for ->hangup_work and ->flip.work handlers to terminate + * Wait for ->hangup_work and ->buf.work handlers to terminate */ flush_scheduled_work(); @@ -2518,17 +2726,15 @@ EXPORT_SYMBOL(do_SAK); /* * This routine is called out of the software interrupt to flush data - * from the flip buffer to the line discipline. + * from the buffer chain to the line discipline. */ static void flush_to_ldisc(void *private_) { struct tty_struct *tty = (struct tty_struct *) private_; - unsigned char *cp; - char *fp; - int count; unsigned long flags; struct tty_ldisc *disc; + struct tty_buffer *tbuf; disc = tty_ldisc_ref(tty); if (disc == NULL) /* !TTY_LDISC */ @@ -2538,28 +2744,23 @@ static void flush_to_ldisc(void *private_) /* * Do it after the next timer tick: */ - schedule_delayed_work(&tty->flip.work, 1); + schedule_delayed_work(&tty->buf.work, 1); goto out; } spin_lock_irqsave(&tty->read_lock, flags); - if (tty->flip.buf_num) { - cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE; - fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE; - tty->flip.buf_num = 0; - tty->flip.char_buf_ptr = tty->flip.char_buf; - tty->flip.flag_buf_ptr = tty->flip.flag_buf; - } else { - cp = tty->flip.char_buf; - fp = tty->flip.flag_buf; - tty->flip.buf_num = 1; - tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE; - tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE; - } - count = tty->flip.count; - tty->flip.count = 0; + while((tbuf = tty->buf.head) != NULL) { + 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); - - disc->receive_buf(tty, cp, fp, count); out: tty_ldisc_deref(disc); } @@ -2654,11 +2855,12 @@ void tty_flip_buffer_push(struct tty_struct *tty) if (tty->low_latency) flush_to_ldisc((void *) tty); else - schedule_delayed_work(&tty->flip.work, 1); + schedule_delayed_work(&tty->buf.work, 1); } EXPORT_SYMBOL(tty_flip_buffer_push); + /* * This subroutine initializes a tty structure. */ @@ -2669,10 +2871,10 @@ static void initialize_tty_struct(struct tty_struct *tty) tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); tty->pgrp = -1; tty->overrun_time = jiffies; - tty->flip.char_buf_ptr = tty->flip.char_buf; - tty->flip.flag_buf_ptr = tty->flip.flag_buf; - INIT_WORK(&tty->flip.work, flush_to_ldisc, tty); - init_MUTEX(&tty->flip.pty_sem); + tty->buf.head = tty->buf.tail = NULL; + tty_buffer_init(tty); + INIT_WORK(&tty->buf.work, flush_to_ldisc, tty); + init_MUTEX(&tty->buf.pty_sem); init_MUTEX(&tty->termios_sem); init_waitqueue_head(&tty->write_wait); init_waitqueue_head(&tty->read_wait);