From 4d18e6eff81e1d4d81d0942d5b7e96904b3b32df Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Fri, 22 Nov 2013 12:09:55 -0500 Subject: tty: Enable configurable tty flip buffer limit Allow driver to configure its maximum flip buffer memory consumption/limit. This is necessary for very-high speed line rates (in excess of 10MB/sec) because the flip buffers can be saturated before the line discipline has a chance to throttle the input. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 97d660ed70c1..2225745060d6 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -61,6 +61,7 @@ struct tty_bufhead { struct tty_buffer sentinel; struct llist_head free; /* Free queue head */ atomic_t memory_used; /* In-use buffers excluding free list */ + int mem_limit; struct tty_buffer *tail; /* Active buffer */ }; /* -- cgit v1.2.3 From 5dda4ca5585270c7d6854da5f83e8e8d3e157094 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Fri, 22 Nov 2013 12:09:56 -0500 Subject: tty: Rename tty buffer memory_used field Trim up the memory_used field name to mem_used. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 12 ++++++------ include/linux/tty.h | 2 +- 2 files changed, 7 insertions(+), 7 deletions(-) (limited to 'include/linux/tty.h') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 57eb34b2ec24..e8f22f833b4e 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -89,7 +89,7 @@ void tty_buffer_unlock_exclusive(struct tty_port *port) int tty_buffer_space_avail(struct tty_port *port) { - int space = port->buf.mem_limit - atomic_read(&port->buf.memory_used); + int space = port->buf.mem_limit - atomic_read(&port->buf.mem_used); return max(space, 0); } @@ -129,7 +129,7 @@ void tty_buffer_free_all(struct tty_port *port) buf->head = &buf->sentinel; buf->tail = &buf->sentinel; - atomic_set(&buf->memory_used, 0); + atomic_set(&buf->mem_used, 0); } /** @@ -162,7 +162,7 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) /* Should possibly check if this fails for the largest buffer we have queued and recycle that ? */ - if (atomic_read(&port->buf.memory_used) > port->buf.mem_limit) + if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit) return NULL; p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); if (p == NULL) @@ -170,7 +170,7 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) found: tty_buffer_reset(p, size); - atomic_add(size, &port->buf.memory_used); + atomic_add(size, &port->buf.mem_used); return p; } @@ -188,7 +188,7 @@ static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b) struct tty_bufhead *buf = &port->buf; /* Dumb strategy for now - should keep some stats */ - WARN_ON(atomic_sub_return(b->size, &buf->memory_used) < 0); + WARN_ON(atomic_sub_return(b->size, &buf->mem_used) < 0); if (b->size > MIN_TTYB_SIZE) kfree(b); @@ -533,7 +533,7 @@ void tty_buffer_init(struct tty_port *port) buf->head = &buf->sentinel; buf->tail = &buf->sentinel; init_llist_head(&buf->free); - atomic_set(&buf->memory_used, 0); + atomic_set(&buf->mem_used, 0); atomic_set(&buf->priority, 0); INIT_WORK(&buf->work, flush_to_ldisc); buf->mem_limit = TTYB_DEFAULT_MEM_LIMIT; diff --git a/include/linux/tty.h b/include/linux/tty.h index 2225745060d6..38fcc0574ba9 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -60,7 +60,7 @@ struct tty_bufhead { atomic_t priority; struct tty_buffer sentinel; struct llist_head free; /* Free queue head */ - atomic_t memory_used; /* In-use buffers excluding free list */ + atomic_t mem_used; /* In-use buffers excluding free list */ int mem_limit; struct tty_buffer *tail; /* Active buffer */ }; -- cgit v1.2.3 From acc0f67f307f52f7aec1cffdc40a786c15dd21d9 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Mon, 9 Dec 2013 09:23:52 -0500 Subject: tty: Halve flip buffer GFP_ATOMIC memory consumption tty flip buffers use GFP_ATOMIC allocations for received data which is to be processed by the line discipline. For each byte received, an extra byte is used to indicate the error status of that byte. Instead, if the received data is error-free, encode the entire buffer without status bytes. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 45 +++++++++++++++++++++++++++++++++++---------- include/linux/tty.h | 4 ++++ include/linux/tty_flip.h | 8 ++++++-- 3 files changed, 45 insertions(+), 12 deletions(-) (limited to 'include/linux/tty.h') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 08835a6dd022..3002e20e10d7 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -101,6 +101,7 @@ static void tty_buffer_reset(struct tty_buffer *p, size_t size) p->next = NULL; p->commit = 0; p->read = 0; + p->flags = 0; } /** @@ -229,31 +230,49 @@ void tty_buffer_flush(struct tty_struct *tty) * tty_buffer_request_room - grow tty buffer if needed * @tty: tty structure * @size: size desired + * @flags: buffer flags if new buffer allocated (default = 0) * * Make at least size bytes of linear space available for the tty * buffer. If we fail return the size we managed to find. + * + * Will change over to a new buffer if the current buffer is encoded as + * TTY_NORMAL (so has no flags buffer) and the new buffer requires + * a flags buffer. */ -int tty_buffer_request_room(struct tty_port *port, size_t size) +static int __tty_buffer_request_room(struct tty_port *port, size_t size, + int flags) { struct tty_bufhead *buf = &port->buf; struct tty_buffer *b, *n; - int left; + int left, change; b = buf->tail; - left = b->size - b->used; + if (b->flags & TTYB_NORMAL) + left = 2 * b->size - b->used; + else + left = b->size - b->used; - if (left < size) { + change = (b->flags & TTYB_NORMAL) && (~flags & TTYB_NORMAL); + if (change || left < size) { /* This is the slow path - looking for new buffers to use */ if ((n = tty_buffer_alloc(port, size)) != NULL) { + n->flags = flags; buf->tail = n; b->commit = b->used; smp_mb(); b->next = n; - } else + } else if (change) + size = 0; + else size = left; } return size; } + +int tty_buffer_request_room(struct tty_port *port, size_t size) +{ + return __tty_buffer_request_room(port, size, 0); +} EXPORT_SYMBOL_GPL(tty_buffer_request_room); /** @@ -273,12 +292,14 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port, int copied = 0; do { int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); - int space = tty_buffer_request_room(port, goal); + int flags = (flag == TTY_NORMAL) ? TTYB_NORMAL : 0; + int space = __tty_buffer_request_room(port, goal, flags); struct tty_buffer *tb = port->buf.tail; if (unlikely(space == 0)) break; memcpy(char_buf_ptr(tb, tb->used), chars, space); - memset(flag_buf_ptr(tb, tb->used), flag, space); + if (~tb->flags & TTYB_NORMAL) + memset(flag_buf_ptr(tb, tb->used), flag, space); tb->used += space; copied += space; chars += space; @@ -361,11 +382,12 @@ EXPORT_SYMBOL(tty_schedule_flip); int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars, size_t size) { - int space = tty_buffer_request_room(port, size); + int space = __tty_buffer_request_room(port, size, TTYB_NORMAL); if (likely(space)) { struct tty_buffer *tb = port->buf.tail; *chars = char_buf_ptr(tb, tb->used); - memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space); + if (~tb->flags & TTYB_NORMAL) + memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space); tb->used += space; } return space; @@ -378,7 +400,10 @@ receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count) { struct tty_ldisc *disc = tty->ldisc; unsigned char *p = char_buf_ptr(head, head->read); - char *f = flag_buf_ptr(head, head->read); + char *f = NULL; + + if (~head->flags & TTYB_NORMAL) + f = flag_buf_ptr(head, head->read); if (disc->ops->receive_buf2) count = disc->ops->receive_buf2(tty, p, f, count); diff --git a/include/linux/tty.h b/include/linux/tty.h index 38fcc0574ba9..ad98b4376968 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -39,10 +39,14 @@ struct tty_buffer { int size; int commit; int read; + int flags; /* Data points here */ unsigned long data[0]; }; +/* Values for .flags field of tty_buffer */ +#define TTYB_NORMAL 1 /* buffer has no flags buffer */ + static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs) { return ((unsigned char *)b->data) + ofs; diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h index 3f821e98af0f..c28dd523f96e 100644 --- a/include/linux/tty_flip.h +++ b/include/linux/tty_flip.h @@ -17,8 +17,12 @@ static inline int tty_insert_flip_char(struct tty_port *port, unsigned char ch, char flag) { struct tty_buffer *tb = port->buf.tail; - if (tb && tb->used < tb->size) { - *flag_buf_ptr(tb, tb->used) = flag; + int change; + + change = (tb->flags & TTYB_NORMAL) && (flag != TTY_NORMAL); + if (!change && tb->used < tb->size) { + if (~tb->flags & TTYB_NORMAL) + *flag_buf_ptr(tb, tb->used) = flag; *char_buf_ptr(tb, tb->used++) = ch; return 1; } -- cgit v1.2.3 From e12348c6d0f720f0f8d665847057b5752e563982 Mon Sep 17 00:00:00 2001 From: Chuansheng Liu Date: Wed, 18 Dec 2013 15:48:23 +0800 Subject: tty: Removing the deprecated function tty_vhangup_locked() The function tty_vhangup_locked() was deprecated, removed it from the tty.h also. Signed-off-by: Liu, Chuansheng Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index ad98b4376968..978d0f09d039 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -427,7 +427,6 @@ extern int is_ignored(int sig); extern int tty_signal(int sig, struct tty_struct *tty); extern void tty_hangup(struct tty_struct *tty); extern void tty_vhangup(struct tty_struct *tty); -extern void tty_vhangup_locked(struct tty_struct *tty); extern void tty_unhangup(struct file *filp); extern int tty_hung_up_p(struct file *filp); extern void do_SAK(struct tty_struct *tty); -- cgit v1.2.3 From e58b57a354cade526266f60d3d936eed7c421c90 Mon Sep 17 00:00:00 2001 From: Andrew Lunn Date: Sun, 29 Dec 2013 19:23:16 +0100 Subject: tty: Add C_CMSPAR(tty) Add the missing C_CMSPAR(tty) macro. Signed-off-by: Andrew Lunn Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 97d660ed70c1..e53e90ed3f19 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -137,6 +137,7 @@ struct tty_bufhead { #define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL) #define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD) #define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS) +#define C_CMSPAR(tty) _C_FLAG((tty), CMSPAR) #define L_ISIG(tty) _L_FLAG((tty), ISIG) #define L_ICANON(tty) _L_FLAG((tty), ICANON) -- cgit v1.2.3