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-rw-r--r--drivers/char/cyclades.c6
-rw-r--r--drivers/char/esp.c4
-rw-r--r--drivers/char/tty_io.c77
-rw-r--r--include/linux/kbd_kern.h5
-rw-r--r--include/linux/tty.h2
-rw-r--r--include/linux/tty_flip.h7
6 files changed, 68 insertions, 33 deletions
diff --git a/drivers/char/cyclades.c b/drivers/char/cyclades.c
index 39c61a71176e..cc7acf877dc0 100644
--- a/drivers/char/cyclades.c
+++ b/drivers/char/cyclades.c
@@ -1233,7 +1233,7 @@ cyy_interrupt(int irq, void *dev_id, struct pt_regs *regs)
}
info->idle_stats.recv_idle = jiffies;
}
- schedule_delayed_work(&tty->buf.work, 1);
+ tty_schedule_flip(tty);
}
/* end of service */
cy_writeb(base_addr+(CyRIR<<index), (save_xir & 0x3f));
@@ -1606,7 +1606,7 @@ cyz_handle_rx(struct cyclades_port *info,
}
#endif
info->idle_stats.recv_idle = jiffies;
- schedule_delayed_work(&tty->buf.work, 1);
+ tty_schedule_flip(tty);
}
/* Update rx_get */
cy_writel(&buf_ctrl->rx_get, new_rx_get);
@@ -1809,7 +1809,7 @@ cyz_handle_cmd(struct cyclades_card *cinfo)
if(delta_count)
cy_sched_event(info, Cy_EVENT_DELTA_WAKEUP);
if(special_count)
- schedule_delayed_work(&tty->buf.work, 1);
+ tty_schedule_flip(tty);
}
}
diff --git a/drivers/char/esp.c b/drivers/char/esp.c
index 3f3ac039f4d9..57539d8f9f7c 100644
--- a/drivers/char/esp.c
+++ b/drivers/char/esp.c
@@ -359,7 +359,7 @@ static inline void receive_chars_pio(struct esp_struct *info, int num_bytes)
}
}
- schedule_delayed_work(&tty->buf.work, 1);
+ tty_schedule_flip(tty);
info->stat_flags &= ~ESP_STAT_RX_TIMEOUT;
release_pio_buffer(pio_buf);
@@ -426,7 +426,7 @@ static inline void receive_chars_dma_done(struct esp_struct *info,
}
tty_insert_flip_char(tty, dma_buffer[num_bytes - 1], statflag);
}
- schedule_delayed_work(&tty->buf.work, 1);
+ tty_schedule_flip(tty);
}
if (dma_bytes != num_bytes) {
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index eb8b5be4e249..076e07c1da38 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 +267,7 @@ static struct tty_buffer *tty_buffer_alloc(size_t size)
p->used = 0;
p->size = size;
p->next = NULL;
+ p->active = 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); */
@@ -312,25 +314,36 @@ 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;
+ } 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 +409,12 @@ 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 +431,12 @@ 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;
}
@@ -2747,20 +2764,20 @@ static void flush_to_ldisc(void *private_)
schedule_delayed_work(&tty->buf.work, 1);
goto out;
}
- spin_lock_irqsave(&tty->read_lock, flags);
- while((tbuf = tty->buf.head) != NULL) {
+ spin_lock_irqsave(&tty->buf.lock, flags);
+ while((tbuf = tty->buf.head) != NULL && !tbuf->active) {
tty->buf.head = tbuf->next;
if (tty->buf.head == NULL)
tty->buf.tail = NULL;
- spin_unlock_irqrestore(&tty->read_lock, flags);
+ spin_unlock_irqrestore(&tty->buf.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);
+ spin_lock_irqsave(&tty->buf.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 +2869,12 @@ 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;
+ spin_unlock_irqrestore(&tty->buf.lock, flags);
+
if (tty->low_latency)
flush_to_ldisc((void *) tty);
else
diff --git a/include/linux/kbd_kern.h b/include/linux/kbd_kern.h
index 45f625d7d0b2..3aed37314ab8 100644
--- a/include/linux/kbd_kern.h
+++ b/include/linux/kbd_kern.h
@@ -151,6 +151,11 @@ extern unsigned int keymap_count;
static inline void con_schedule_flip(struct tty_struct *t)
{
+ unsigned long flags;
+ spin_lock_irqsave(&t->buf.lock, flags);
+ if (t->buf.tail != NULL)
+ t->buf.tail->active = 0;
+ spin_unlock_irqrestore(&t->buf.lock, flags);
schedule_work(&t->buf.work);
}
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 3787102e4b12..a7bd3b4558d2 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -57,6 +57,7 @@ struct tty_buffer {
unsigned char *flag_buf_ptr;
int used;
int size;
+ int active;
/* Data points here */
unsigned long data[0];
};
@@ -64,6 +65,7 @@ struct tty_buffer {
struct tty_bufhead {
struct work_struct work;
struct semaphore pty_sem;
+ spinlock_t lock;
struct tty_buffer *head; /* Queue head */
struct tty_buffer *tail; /* Active buffer */
struct tty_buffer *free; /* Free queue head */
diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h
index be1400e82482..82961eb19888 100644
--- a/include/linux/tty_flip.h
+++ b/include/linux/tty_flip.h
@@ -17,7 +17,7 @@ _INLINE_ int tty_insert_flip_char(struct tty_struct *tty,
unsigned char ch, char flag)
{
struct tty_buffer *tb = tty->buf.tail;
- if (tb && tb->used < tb->size) {
+ if (tb && tb->active && tb->used < tb->size) {
tb->flag_buf_ptr[tb->used] = flag;
tb->char_buf_ptr[tb->used++] = ch;
return 1;
@@ -27,6 +27,11 @@ _INLINE_ int tty_insert_flip_char(struct tty_struct *tty,
_INLINE_ void tty_schedule_flip(struct tty_struct *tty)
{
+ unsigned long flags;
+ spin_lock_irqsave(&tty->buf.lock, flags);
+ if (tty->buf.tail != NULL)
+ tty->buf.tail->active = 0;
+ spin_unlock_irqrestore(&tty->buf.lock, flags);
schedule_delayed_work(&tty->buf.work, 1);
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.