From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/drivers/tty/tty_buffer.c | 92 ++++++++++++++++++++++++++++++----------------
1 files changed, 60 insertions(+), 32 deletions(-)
diff --git a/kernel/drivers/tty/tty_buffer.c b/kernel/drivers/tty/tty_buffer.c
index 6b0cb63..9f23798 100644
--- a/kernel/drivers/tty/tty_buffer.c
+++ b/kernel/drivers/tty/tty_buffer.c
@@ -17,7 +17,7 @@
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/ratelimit.h>
-
+#include "tty.h"
#define MIN_TTYB_SIZE 256
#define TTYB_ALIGN_MASK 255
@@ -42,7 +42,7 @@
* tty_buffer_lock_exclusive - gain exclusive access to buffer
* tty_buffer_unlock_exclusive - release exclusive access
*
- * @port - tty_port owning the flip buffer
+ * @port: tty port owning the flip buffer
*
* Guarantees safe use of the line discipline's receive_buf() method by
* excluding the buffer work and any pending flush from using the flip
@@ -78,7 +78,7 @@
/**
* tty_buffer_space_avail - return unused buffer space
- * @port - tty_port owning the flip buffer
+ * @port: tty port owning the flip buffer
*
* Returns the # of bytes which can be written by the driver without
* reaching the buffer limit.
@@ -107,7 +107,7 @@
/**
* tty_buffer_free_all - free buffers used by a tty
- * @tty: tty to free from
+ * @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
@@ -118,9 +118,12 @@
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);
}
@@ -132,12 +135,14 @@
buf->head = &buf->sentinel;
buf->tail = &buf->sentinel;
- atomic_set(&buf->mem_used, 0);
+ 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
- * @tty: tty device
+ * @port: tty port
* @size: desired size (characters)
*
* Allocate a new tty buffer to hold the desired number of characters.
@@ -167,7 +172,8 @@
have queued and recycle that ? */
if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit)
return NULL;
- p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
+ p = kmalloc(sizeof(struct tty_buffer) + 2 * size,
+ GFP_ATOMIC | __GFP_NOWARN);
if (p == NULL)
return NULL;
@@ -179,7 +185,7 @@
/**
* tty_buffer_free - free a tty buffer
- * @tty: tty owning the 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
@@ -238,7 +244,7 @@
/**
* tty_buffer_request_room - grow tty buffer if needed
- * @tty: tty structure
+ * @port: tty port
* @size: size desired
* @flags: buffer flags if new buffer allocated (default = 0)
*
@@ -389,27 +395,6 @@
EXPORT_SYMBOL(__tty_insert_flip_char);
/**
- * tty_schedule_flip - push characters to ldisc
- * @port: tty port to push from
- *
- * Takes any pending buffers and transfers their ownership to the
- * ldisc side of the queue. It then schedules those characters for
- * processing by the line discipline.
- */
-
-void tty_schedule_flip(struct tty_port *port)
-{
- struct tty_bufhead *buf = &port->buf;
-
- /* paired w/ acquire in flush_to_ldisc(); ensures
- * flush_to_ldisc() sees buffer data.
- */
- smp_store_release(&buf->tail->commit, buf->tail->used);
- queue_work(system_unbound_wq, &buf->work);
-}
-EXPORT_SYMBOL(tty_schedule_flip);
-
-/**
* tty_prepare_flip_string - make room for characters
* @port: tty port
* @chars: return pointer for character write area
@@ -538,6 +523,15 @@
}
+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 - terminal
* @port: tty port to push
@@ -551,13 +545,47 @@
void tty_flip_buffer_push(struct tty_port *port)
{
- tty_schedule_flip(port);
+ struct tty_bufhead *buf = &port->buf;
+
+ tty_flip_buffer_commit(buf->tail);
+ queue_work(system_unbound_wq, &buf->work);
}
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 unsigned char *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);
+
+ queue_work(system_unbound_wq, &buf->work);
+
+ return size;
+}
+
+/**
* tty_buffer_init - prepare a tty buffer structure
- * @tty: tty to initialise
+ * @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.
--
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