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 --- drivers/tty/tty_buffer.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index c043136fbe51..57eb34b2ec24 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -26,7 +26,7 @@ * Byte threshold to limit memory consumption for flip buffers. * The actual memory limit is > 2x this amount. */ -#define TTYB_MEM_LIMIT 65536 +#define TTYB_DEFAULT_MEM_LIMIT 65536 /* * We default to dicing tty buffer allocations to this many characters @@ -89,7 +89,7 @@ void tty_buffer_unlock_exclusive(struct tty_port *port) int tty_buffer_space_avail(struct tty_port *port) { - int space = TTYB_MEM_LIMIT - atomic_read(&port->buf.memory_used); + int space = port->buf.mem_limit - atomic_read(&port->buf.memory_used); return max(space, 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) > TTYB_MEM_LIMIT) + if (atomic_read(&port->buf.memory_used) > port->buf.mem_limit) return NULL; p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); if (p == NULL) @@ -536,4 +536,22 @@ void tty_buffer_init(struct tty_port *port) atomic_set(&buf->memory_used, 0); atomic_set(&buf->priority, 0); INIT_WORK(&buf->work, flush_to_ldisc); + buf->mem_limit = TTYB_DEFAULT_MEM_LIMIT; } + +/** + * tty_buffer_set_limit - change the tty buffer memory limit + * @port: tty port to change + * + * Change the tty buffer memory limit. + * Must be called before the other tty buffer functions are used. + */ + +int tty_buffer_set_limit(struct tty_port *port, int limit) +{ + if (limit < MIN_TTYB_SIZE) + return -EINVAL; + port->buf.mem_limit = limit; + return 0; +} +EXPORT_SYMBOL_GPL(tty_buffer_set_limit); -- 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 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/tty/tty_buffer.c') 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; -- cgit v1.2.3 From 7e1e71d1546a28ea0ccc06320987e6c4ab2e1dbe Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Fri, 22 Nov 2013 12:09:57 -0500 Subject: tty: Remove tty_prepare_flip_string_flags() There is no in-tree user of tty_prepare_flip_string_flags(); remove. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 28 ---------------------------- 1 file changed, 28 deletions(-) (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index e8f22f833b4e..6a3620e1cc7a 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -373,34 +373,6 @@ int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars, } EXPORT_SYMBOL_GPL(tty_prepare_flip_string); -/** - * tty_prepare_flip_string_flags - make room for characters - * @port: tty port - * @chars: return pointer for character write area - * @flags: return pointer for status flag write area - * @size: desired size - * - * 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_port *port, - unsigned char **chars, char **flags, size_t size) -{ - int space = tty_buffer_request_room(port, size); - if (likely(space)) { - struct tty_buffer *tb = port->buf.tail; - *chars = char_buf_ptr(tb, tb->used); - *flags = flag_buf_ptr(tb, tb->used); - tb->used += space; - } - return space; -} -EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); - static int receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count) -- cgit v1.2.3 From c4a8dab5806188fb2a752467b63a7fd19bcbf0ec Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Fri, 22 Nov 2013 13:06:08 -0500 Subject: staging/fwserial: Rip out rx buffering Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 6a3620e1cc7a..6454c0a747ef 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -92,6 +92,7 @@ int tty_buffer_space_avail(struct tty_port *port) int space = port->buf.mem_limit - atomic_read(&port->buf.mem_used); return max(space, 0); } +EXPORT_SYMBOL_GPL(tty_buffer_space_avail); static void tty_buffer_reset(struct tty_buffer *p, size_t size) { -- cgit v1.2.3 From 753023dcdd2da515f991aa0e6a65016713f0c24f Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Mon, 2 Dec 2013 16:12:02 -0500 Subject: tty: Fix stale tty_buffer_flush() comment Commit d7a68be4f265be10e24be931c257af30ca55566b, 'tty: Only perform flip buffer flush from tty_buffer_flush()', removed buffer flushing from flush_to_ldisc(). Fix function header comment which describes the former behavior. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 6454c0a747ef..08835a6dd022 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -201,9 +201,7 @@ static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b) * tty_buffer_flush - flush full tty buffers * @tty: tty to flush * - * flush all the buffers containing receive data. If the buffer is - * being processed by flush_to_ldisc then we defer the processing - * to that function + * flush all the buffers containing receive data. * * Locking: takes buffer lock to ensure single-threaded flip buffer * 'consumer' -- 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 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 35 insertions(+), 10 deletions(-) (limited to 'drivers/tty/tty_buffer.c') 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); -- cgit v1.2.3 From f8e87cb4a19aa5f5a1ce22e130da0f4a7fa2d5f3 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Thu, 2 Jan 2014 19:23:47 -0500 Subject: tty: delete non-required instances of include None of these files are actually using any __init type directives and hence don't need to include . Most are just a left over from __devinit and __cpuinit removal, or simply due to code getting copied from one driver to the next. Signed-off-by: Paul Gortmaker Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 3002e20e10d7..765125dff20e 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include #include -- cgit v1.2.3