From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- drivers/tty/tty_buffer.c | 634 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 634 insertions(+) create mode 100644 drivers/tty/tty_buffer.c (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c new file mode 100644 index 000000000..96be90db5 --- /dev/null +++ b/drivers/tty/tty_buffer.c @@ -0,0 +1,634 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Tty buffer allocation management + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "tty.h" + +#define MIN_TTYB_SIZE 256 +#define TTYB_ALIGN_MASK 0xff + +/* + * Byte threshold to limit memory consumption for flip buffers. + * The actual memory limit is > 2x this amount. + */ +#define TTYB_DEFAULT_MEM_LIMIT (640 * 1024UL) + +/* + * We default to dicing tty buffer allocations to this many characters + * in order to avoid multiple page allocations. We know the size of + * tty_buffer itself but it must also be taken into account that the + * buffer is 256 byte aligned. See tty_buffer_find for the allocation + * logic this must match. + */ + +#define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~TTYB_ALIGN_MASK) + +/** + * tty_buffer_lock_exclusive - gain exclusive access to buffer + * @port: tty port owning the flip buffer + * + * Guarantees safe use of the &tty_ldisc_ops.receive_buf() method by excluding + * the buffer work and any pending flush from using the flip buffer. Data can + * continue to be added concurrently to the flip buffer from the driver side. + * + * See also tty_buffer_unlock_exclusive(). + */ +void tty_buffer_lock_exclusive(struct tty_port *port) +{ + struct tty_bufhead *buf = &port->buf; + + atomic_inc(&buf->priority); + mutex_lock(&buf->lock); +} +EXPORT_SYMBOL_GPL(tty_buffer_lock_exclusive); + +static bool tty_buffer_queue_work(struct tty_bufhead *buf) +{ + struct workqueue_struct *flip_wq = READ_ONCE(buf->flip_wq); + + return queue_work(flip_wq ?: system_dfl_wq, &buf->work); +} + +/** + * tty_buffer_unlock_exclusive - release exclusive access + * @port: tty port owning the flip buffer + * + * The buffer work is restarted if there is data in the flip buffer. + * + * See also tty_buffer_lock_exclusive(). + */ +void tty_buffer_unlock_exclusive(struct tty_port *port) +{ + struct tty_bufhead *buf = &port->buf; + bool restart = buf->head->commit != buf->head->read; + + atomic_dec(&buf->priority); + mutex_unlock(&buf->lock); + + if (restart) + tty_buffer_queue_work(buf); +} +EXPORT_SYMBOL_GPL(tty_buffer_unlock_exclusive); + +/** + * tty_buffer_space_avail - return unused buffer space + * @port: tty port owning the flip buffer + * + * Returns: the # of bytes which can be written by the driver without reaching + * the buffer limit. + * + * Note: this does not guarantee that memory is available to write the returned + * # of bytes (use tty_prepare_flip_string() to pre-allocate if memory + * guarantee is required). + */ +unsigned 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) +{ + p->used = 0; + p->size = size; + p->next = NULL; + p->commit = 0; + p->lookahead = 0; + p->read = 0; + p->flags = true; +} + +/** + * tty_buffer_free_all - free buffers used by a tty + * @port: tty port to free from + * + * Remove all the buffers pending on a tty whether queued with data or in the + * free ring. Must be called when the tty is no longer in use. + */ +void tty_buffer_free_all(struct tty_port *port) +{ + struct tty_bufhead *buf = &port->buf; + struct tty_buffer *p, *next; + struct llist_node *llist; + unsigned int freed = 0; + int still_used; + + while ((p = buf->head) != NULL) { + buf->head = p->next; + freed += p->size; + if (p->size > 0) + kfree(p); + } + llist = llist_del_all(&buf->free); + llist_for_each_entry_safe(p, next, llist, free) + kfree(p); + + tty_buffer_reset(&buf->sentinel, 0); + buf->head = &buf->sentinel; + buf->tail = &buf->sentinel; + + still_used = atomic_xchg(&buf->mem_used, 0); + WARN(still_used != freed, "we still have not freed %d bytes!", + still_used - freed); +} + +/** + * tty_buffer_alloc - allocate a tty buffer + * @port: tty port + * @size: desired size (characters) + * + * Allocate a new tty buffer to hold the desired number of characters. We + * round our buffers off in 256 character chunks to get better allocation + * behaviour. + * + * Returns: %NULL if out of memory or the allocation would exceed the per + * device queue. + */ +static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) +{ + struct llist_node *free; + struct tty_buffer *p; + + /* Round the buffer size out */ + size = __ALIGN_MASK(size, TTYB_ALIGN_MASK); + + if (size <= MIN_TTYB_SIZE) { + free = llist_del_first(&port->buf.free); + if (free) { + p = llist_entry(free, struct tty_buffer, free); + goto found; + } + } + + /* Should possibly check if this fails for the largest buffer we + * have queued and recycle that ? + */ + if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit) + return NULL; + p = kmalloc_flex(*p, data, 2 * size, GFP_ATOMIC | __GFP_NOWARN); + if (p == NULL) + return NULL; + +found: + tty_buffer_reset(p, size); + atomic_add(size, &port->buf.mem_used); + return p; +} + +/** + * tty_buffer_free - free a tty buffer + * @port: tty port owning the buffer + * @b: the buffer to free + * + * Free a tty buffer, or add it to the free list according to our internal + * strategy. + */ +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->mem_used) < 0); + + if (b->size > MIN_TTYB_SIZE) + kfree(b); + else if (b->size > 0) + llist_add(&b->free, &buf->free); +} + +/** + * tty_buffer_flush - flush full tty buffers + * @tty: tty to flush + * @ld: optional ldisc ptr (must be referenced) + * + * Flush all the buffers containing receive data. If @ld != %NULL, flush the + * ldisc input buffer. + * + * Locking: takes buffer lock to ensure single-threaded flip buffer 'consumer'. + */ +void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld) +{ + struct tty_port *port = tty->port; + struct tty_bufhead *buf = &port->buf; + struct tty_buffer *next; + + atomic_inc(&buf->priority); + + mutex_lock(&buf->lock); + /* paired w/ release in __tty_buffer_request_room; ensures there are + * no pending memory accesses to the freed buffer + */ + while ((next = smp_load_acquire(&buf->head->next)) != NULL) { + tty_buffer_free(port, buf->head); + buf->head = next; + } + buf->head->read = buf->head->commit; + buf->head->lookahead = buf->head->read; + + if (ld && ld->ops->flush_buffer) + ld->ops->flush_buffer(tty); + + atomic_dec(&buf->priority); + mutex_unlock(&buf->lock); +} + +/** + * __tty_buffer_request_room - grow tty buffer if needed + * @port: tty port + * @size: size desired + * @flags: buffer has to store flags along character data + * + * Make at least @size bytes of linear space available for the tty buffer. + * + * 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. + * + * Returns: the size we managed to find. + */ +static int __tty_buffer_request_room(struct tty_port *port, size_t size, + bool flags) +{ + struct tty_bufhead *buf = &port->buf; + struct tty_buffer *n, *b = buf->tail; + size_t left = (b->flags ? 1 : 2) * b->size - b->used; + bool change = !b->flags && flags; + + if (!change && left >= size) + return size; + + /* This is the slow path - looking for new buffers to use */ + n = tty_buffer_alloc(port, size); + if (n == NULL) + return change ? 0 : left; + + n->flags = flags; + buf->tail = n; + /* + * Paired w/ acquire in flush_to_ldisc() and lookahead_bufs() + * ensures they see all buffer data. + */ + smp_store_release(&b->commit, b->used); + /* + * Paired w/ acquire in flush_to_ldisc() and lookahead_bufs() + * ensures the latest commit value can be read before the head + * is advanced to the next buffer. + */ + smp_store_release(&b->next, n); + + return size; +} + +int tty_buffer_request_room(struct tty_port *port, size_t size) +{ + return __tty_buffer_request_room(port, size, true); +} +EXPORT_SYMBOL_GPL(tty_buffer_request_room); + +size_t __tty_insert_flip_string_flags(struct tty_port *port, const u8 *chars, + const u8 *flags, bool mutable_flags, + size_t size) +{ + bool need_flags = mutable_flags || flags[0] != TTY_NORMAL; + size_t copied = 0; + + do { + size_t goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); + size_t space = __tty_buffer_request_room(port, goal, need_flags); + struct tty_buffer *tb = port->buf.tail; + + if (unlikely(space == 0)) + break; + + memcpy(char_buf_ptr(tb, tb->used), chars, space); + + if (mutable_flags) { + memcpy(flag_buf_ptr(tb, tb->used), flags, space); + flags += space; + } else if (tb->flags) { + memset(flag_buf_ptr(tb, tb->used), flags[0], space); + } else { + /* tb->flags should be available once requested */ + WARN_ON_ONCE(need_flags); + } + + tb->used += space; + copied += space; + chars += 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(__tty_insert_flip_string_flags); + +/** + * tty_prepare_flip_string - make room for characters + * @port: tty port + * @chars: return pointer for character write area + * @size: desired size + * + * Prepare a block of space in the buffer for data. + * + * 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! + * + * Returns: the length available and buffer pointer (@chars) to the space which + * is now allocated and accounted for as ready for normal characters. + */ +size_t tty_prepare_flip_string(struct tty_port *port, u8 **chars, size_t size) +{ + size_t space = __tty_buffer_request_room(port, size, false); + + if (likely(space)) { + struct tty_buffer *tb = port->buf.tail; + + *chars = char_buf_ptr(tb, tb->used); + if (tb->flags) + memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space); + tb->used += space; + } + + return space; +} +EXPORT_SYMBOL_GPL(tty_prepare_flip_string); + +/** + * tty_ldisc_receive_buf - forward data to line discipline + * @ld: line discipline to process input + * @p: char buffer + * @f: %TTY_NORMAL, %TTY_BREAK, etc. flags buffer + * @count: number of bytes to process + * + * Callers other than flush_to_ldisc() need to exclude the kworker from + * concurrent use of the line discipline, see paste_selection(). + * + * Returns: the number of bytes processed. + */ +size_t tty_ldisc_receive_buf(struct tty_ldisc *ld, const u8 *p, const u8 *f, + size_t count) +{ + if (ld->ops->receive_buf2) + count = ld->ops->receive_buf2(ld->tty, p, f, count); + else { + count = min_t(size_t, count, ld->tty->receive_room); + if (count && ld->ops->receive_buf) + ld->ops->receive_buf(ld->tty, p, f, count); + } + return count; +} +EXPORT_SYMBOL_GPL(tty_ldisc_receive_buf); + +static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head) +{ + head->lookahead = max(head->lookahead, head->read); + + while (head) { + struct tty_buffer *next; + unsigned int count; + + /* + * Paired w/ release in __tty_buffer_request_room(); + * ensures commit value read is not stale if the head + * is advancing to the next buffer. + */ + next = smp_load_acquire(&head->next); + /* + * Paired w/ release in __tty_buffer_request_room() or in + * tty_buffer_flush(); ensures we see the committed buffer data. + */ + count = smp_load_acquire(&head->commit) - head->lookahead; + if (!count) { + head = next; + continue; + } + + if (port->client_ops->lookahead_buf) { + u8 *p, *f = NULL; + + p = char_buf_ptr(head, head->lookahead); + if (head->flags) + f = flag_buf_ptr(head, head->lookahead); + + port->client_ops->lookahead_buf(port, p, f, count); + } + + head->lookahead += count; + } +} + +static size_t +receive_buf(struct tty_port *port, struct tty_buffer *head, size_t count) +{ + u8 *p = char_buf_ptr(head, head->read); + const u8 *f = NULL; + size_t n; + + if (head->flags) + f = flag_buf_ptr(head, head->read); + + n = port->client_ops->receive_buf(port, p, f, count); + if (n > 0) + memset(p, 0, n); + return n; +} + +/** + * flush_to_ldisc - flush data from buffer to ldisc + * @work: tty structure passed from work queue. + * + * This routine is called out of the software interrupt to flush data from the + * buffer chain to the line discipline. + * + * The receive_buf() method is single threaded for each tty instance. + * + * Locking: takes buffer lock to ensure single-threaded flip buffer 'consumer'. + */ +static void flush_to_ldisc(struct work_struct *work) +{ + struct tty_port *port = container_of(work, struct tty_port, buf.work); + struct tty_bufhead *buf = &port->buf; + + mutex_lock(&buf->lock); + + while (1) { + struct tty_buffer *head = buf->head; + struct tty_buffer *next; + size_t count, rcvd; + + /* Ldisc or user is trying to gain exclusive access */ + if (atomic_read(&buf->priority)) + break; + + /* paired w/ release in __tty_buffer_request_room(); + * ensures commit value read is not stale if the head + * is advancing to the next buffer + */ + next = smp_load_acquire(&head->next); + /* paired w/ release in __tty_buffer_request_room() or in + * tty_buffer_flush(); ensures we see the committed buffer data + */ + count = smp_load_acquire(&head->commit) - head->read; + if (!count) { + if (next == NULL) + break; + buf->head = next; + tty_buffer_free(port, head); + continue; + } + + rcvd = receive_buf(port, head, count); + head->read += rcvd; + if (rcvd < count) + lookahead_bufs(port, head); + if (!rcvd) + break; + + cond_resched(); + } + + mutex_unlock(&buf->lock); + +} + +static inline void tty_flip_buffer_commit(struct tty_buffer *tail) +{ + /* + * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees + * buffer data. + */ + smp_store_release(&tail->commit, tail->used); +} + +/** + * tty_flip_buffer_push - push terminal buffers + * @port: tty port to push + * + * Queue a push of the terminal flip buffers to the line discipline. Can be + * called from IRQ/atomic context. + * + * In the event of the queue being busy for flipping the work will be held off + * and retried later. + */ +void tty_flip_buffer_push(struct tty_port *port) +{ + struct tty_bufhead *buf = &port->buf; + + tty_flip_buffer_commit(buf->tail); + tty_buffer_queue_work(buf); +} +EXPORT_SYMBOL(tty_flip_buffer_push); + +/** + * tty_insert_flip_string_and_push_buffer - add characters to the tty buffer and + * push + * @port: tty port + * @chars: characters + * @size: size + * + * The function combines tty_insert_flip_string() and tty_flip_buffer_push() + * with the exception of properly holding the @port->lock. + * + * To be used only internally (by pty currently). + * + * Returns: the number added. + */ +int tty_insert_flip_string_and_push_buffer(struct tty_port *port, + const u8 *chars, size_t size) +{ + struct tty_bufhead *buf = &port->buf; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + size = tty_insert_flip_string(port, chars, size); + if (size) + tty_flip_buffer_commit(buf->tail); + spin_unlock_irqrestore(&port->lock, flags); + + tty_buffer_queue_work(buf); + + return size; +} + +/** + * tty_buffer_init - prepare a tty buffer structure + * @port: tty port to initialise + * + * Set up the initial state of the buffer management for a tty device. Must be + * called before the other tty buffer functions are used. + */ +void tty_buffer_init(struct tty_port *port) +{ + struct tty_bufhead *buf = &port->buf; + + mutex_init(&buf->lock); + tty_buffer_reset(&buf->sentinel, 0); + buf->head = &buf->sentinel; + buf->tail = &buf->sentinel; + init_llist_head(&buf->free); + 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; +} + +/** + * tty_buffer_set_limit - change the tty buffer memory limit + * @port: tty port to change + * @limit: memory limit to set + * + * 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); + +/* slave ptys can claim nested buffer lock when handling BRK and INTR */ +void tty_buffer_set_lock_subclass(struct tty_port *port) +{ + lockdep_set_subclass(&port->buf.lock, TTY_LOCK_SLAVE); +} + +bool tty_buffer_restart_work(struct tty_port *port) +{ + return tty_buffer_queue_work(&port->buf); +} + +bool tty_buffer_cancel_work(struct tty_port *port) +{ + return cancel_work_sync(&port->buf.work); +} + +void tty_buffer_flush_work(struct tty_port *port) +{ + flush_work(&port->buf.work); +} -- cgit v1.3.1