change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/drivers/tty/tty_buffer.c
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@@ -17,7 +17,7 @@
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 #include <linux/delay.h>
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 #include <linux/module.h>
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 #include <linux/ratelimit.h>
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-
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+#include "tty.h"
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 #define MIN_TTYB_SIZE	256
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 #define TTYB_ALIGN_MASK	255
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@@ -42,7 +42,7 @@
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  *	tty_buffer_lock_exclusive	-	gain exclusive access to buffer
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  *	tty_buffer_unlock_exclusive	-	release exclusive access
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  *
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- *	@port - tty_port owning the flip buffer
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+ *	@port: tty port owning the flip buffer
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  *
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  *	Guarantees safe use of the line discipline's receive_buf() method by
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  *	excluding the buffer work and any pending flush from using the flip
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@@ -78,7 +78,7 @@
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 /**
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  *	tty_buffer_space_avail	-	return unused buffer space
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- *	@port - tty_port owning the flip buffer
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+ *	@port: tty port owning the flip buffer
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  *
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  *	Returns the # of bytes which can be written by the driver without
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  *	reaching the buffer limit.
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@@ -107,7 +107,7 @@
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 /**
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  *	tty_buffer_free_all		-	free buffers used by a tty
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- *	@tty: tty to free from
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+ *	@port: tty port to free from
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  *
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  *	Remove all the buffers pending on a tty whether queued with data
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  *	or in the free ring. Must be called when the tty is no longer in use
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@@ -118,9 +118,12 @@
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 	struct tty_bufhead *buf = &port->buf;
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 	struct tty_buffer *p, *next;
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 	struct llist_node *llist;
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+	unsigned int freed = 0;
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+	int still_used;
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 	while ((p = buf->head) != NULL) {
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 		buf->head = p->next;
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+		freed += p->size;
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 		if (p->size > 0)
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 			kfree(p);
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 	}
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@@ -132,12 +135,14 @@
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 	buf->head = &buf->sentinel;
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 	buf->tail = &buf->sentinel;
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-	atomic_set(&buf->mem_used, 0);
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+	still_used = atomic_xchg(&buf->mem_used, 0);
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+	WARN(still_used != freed, "we still have not freed %d bytes!",
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+			still_used - freed);
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 }
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 /**
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  *	tty_buffer_alloc	-	allocate a tty buffer
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- *	@tty: tty device
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+ *	@port: tty port
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  *	@size: desired size (characters)
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  *
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  *	Allocate a new tty buffer to hold the desired number of characters.
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@@ -167,7 +172,8 @@
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 	   have queued and recycle that ? */
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 	if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit)
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 		return NULL;
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-	p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
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+	p = kmalloc(sizeof(struct tty_buffer) + 2 * size,
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+		    GFP_ATOMIC | __GFP_NOWARN);
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 	if (p == NULL)
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 		return NULL;
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@@ -179,7 +185,7 @@
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 /**
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  *	tty_buffer_free		-	free a tty buffer
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- *	@tty: tty owning the buffer
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+ *	@port: tty port owning the buffer
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  *	@b: the buffer to free
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  *
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  *	Free a tty buffer, or add it to the free list according to our
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@@ -238,7 +244,7 @@
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 /**
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  *	tty_buffer_request_room		-	grow tty buffer if needed
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- *	@tty: tty structure
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+ *	@port: tty port
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  *	@size: size desired
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  *	@flags: buffer flags if new buffer allocated (default = 0)
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  *
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@@ -389,27 +395,6 @@
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 EXPORT_SYMBOL(__tty_insert_flip_char);
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 /**
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- *	tty_schedule_flip	-	push characters to ldisc
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- *	@port: tty port to push from
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- *
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- *	Takes any pending buffers and transfers their ownership to the
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- *	ldisc side of the queue. It then schedules those characters for
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- *	processing by the line discipline.
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- */
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-
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-void tty_schedule_flip(struct tty_port *port)
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-{
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-	struct tty_bufhead *buf = &port->buf;
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-
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-	/* paired w/ acquire in flush_to_ldisc(); ensures
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-	 * flush_to_ldisc() sees buffer data.
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-	 */
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-	smp_store_release(&buf->tail->commit, buf->tail->used);
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-	queue_work(system_unbound_wq, &buf->work);
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-}
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-EXPORT_SYMBOL(tty_schedule_flip);
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-
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-/**
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  *	tty_prepare_flip_string		-	make room for characters
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  *	@port: tty port
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  *	@chars: return pointer for character write area
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@@ -538,6 +523,15 @@
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 }
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+static inline void tty_flip_buffer_commit(struct tty_buffer *tail)
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+{
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+	/*
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+	 * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees
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+	 * buffer data.
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+	 */
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+	smp_store_release(&tail->commit, tail->used);
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+}
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+
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 /**
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  *	tty_flip_buffer_push	-	terminal
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  *	@port: tty port to push
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@@ -551,13 +545,47 @@
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 void tty_flip_buffer_push(struct tty_port *port)
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 {
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-	tty_schedule_flip(port);
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+	struct tty_bufhead *buf = &port->buf;
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+
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+	tty_flip_buffer_commit(buf->tail);
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+	queue_work(system_unbound_wq, &buf->work);
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 }
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 EXPORT_SYMBOL(tty_flip_buffer_push);
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 /**
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+ * tty_insert_flip_string_and_push_buffer - add characters to the tty buffer and
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+ *	push
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+ * @port: tty port
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+ * @chars: characters
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+ * @size: size
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+ *
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+ * The function combines tty_insert_flip_string() and tty_flip_buffer_push()
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+ * with the exception of properly holding the @port->lock.
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+ *
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+ * To be used only internally (by pty currently).
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+ *
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+ * Returns: the number added.
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+ */
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+int tty_insert_flip_string_and_push_buffer(struct tty_port *port,
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+		const unsigned char *chars, size_t size)
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+{
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+	struct tty_bufhead *buf = &port->buf;
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+	unsigned long flags;
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+
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+	spin_lock_irqsave(&port->lock, flags);
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+	size = tty_insert_flip_string(port, chars, size);
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+	if (size)
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+		tty_flip_buffer_commit(buf->tail);
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+	spin_unlock_irqrestore(&port->lock, flags);
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+
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+	queue_work(system_unbound_wq, &buf->work);
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+
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+	return size;
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+}
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+
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+/**
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  *	tty_buffer_init		-	prepare a tty buffer structure
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- *	@tty: tty to initialise
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+ *	@port: tty port to initialise
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  *
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  *	Set up the initial state of the buffer management for a tty device.
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  *	Must be called before the other tty buffer functions are used.