![Daniel Walker](/assets/img/avatar_default.png)
The port_sem is already used as a mutex since it's using DECLARE_MUTEX(), but the underlying construct is still a semaphore .. This patch switches it over to a struct mutex. Signed-off-by: Daniel Walker <dwalker@mvista.com> Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
305 lines
6.5 KiB
C
305 lines
6.5 KiB
C
/*
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* Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
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* Licensed under the GPL
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*/
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#include "linux/completion.h"
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#include "linux/interrupt.h"
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#include "linux/list.h"
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#include "linux/mutex.h"
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#include "asm/atomic.h"
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#include "init.h"
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#include "irq_kern.h"
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#include "os.h"
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#include "port.h"
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struct port_list {
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struct list_head list;
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atomic_t wait_count;
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int has_connection;
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struct completion done;
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int port;
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int fd;
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spinlock_t lock;
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struct list_head pending;
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struct list_head connections;
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};
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struct port_dev {
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struct port_list *port;
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int helper_pid;
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int telnetd_pid;
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};
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struct connection {
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struct list_head list;
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int fd;
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int helper_pid;
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int socket[2];
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int telnetd_pid;
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struct port_list *port;
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};
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static irqreturn_t pipe_interrupt(int irq, void *data)
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{
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struct connection *conn = data;
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int fd;
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fd = os_rcv_fd(conn->socket[0], &conn->helper_pid);
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if (fd < 0) {
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if (fd == -EAGAIN)
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return IRQ_NONE;
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printk(KERN_ERR "pipe_interrupt : os_rcv_fd returned %d\n",
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-fd);
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os_close_file(conn->fd);
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}
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list_del(&conn->list);
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conn->fd = fd;
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list_add(&conn->list, &conn->port->connections);
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complete(&conn->port->done);
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return IRQ_HANDLED;
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}
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#define NO_WAITER_MSG \
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"****\n" \
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"There are currently no UML consoles waiting for port connections.\n" \
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"Either disconnect from one to make it available or activate some more\n" \
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"by enabling more consoles in the UML /etc/inittab.\n" \
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"****\n"
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static int port_accept(struct port_list *port)
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{
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struct connection *conn;
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int fd, socket[2], pid;
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fd = port_connection(port->fd, socket, &pid);
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if (fd < 0) {
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if (fd != -EAGAIN)
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printk(KERN_ERR "port_accept : port_connection "
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"returned %d\n", -fd);
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goto out;
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}
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conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
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if (conn == NULL) {
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printk(KERN_ERR "port_accept : failed to allocate "
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"connection\n");
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goto out_close;
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}
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*conn = ((struct connection)
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{ .list = LIST_HEAD_INIT(conn->list),
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.fd = fd,
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.socket = { socket[0], socket[1] },
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.telnetd_pid = pid,
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.port = port });
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if (um_request_irq(TELNETD_IRQ, socket[0], IRQ_READ, pipe_interrupt,
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IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
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"telnetd", conn)) {
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printk(KERN_ERR "port_accept : failed to get IRQ for "
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"telnetd\n");
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goto out_free;
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}
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if (atomic_read(&port->wait_count) == 0) {
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os_write_file(fd, NO_WAITER_MSG, sizeof(NO_WAITER_MSG));
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printk(KERN_ERR "No one waiting for port\n");
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}
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list_add(&conn->list, &port->pending);
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return 1;
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out_free:
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kfree(conn);
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out_close:
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os_close_file(fd);
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os_kill_process(pid, 1);
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out:
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return 0;
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}
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static DEFINE_MUTEX(ports_mutex);
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static LIST_HEAD(ports);
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static void port_work_proc(struct work_struct *unused)
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{
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struct port_list *port;
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struct list_head *ele;
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unsigned long flags;
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local_irq_save(flags);
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list_for_each(ele, &ports) {
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port = list_entry(ele, struct port_list, list);
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if (!port->has_connection)
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continue;
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reactivate_fd(port->fd, ACCEPT_IRQ);
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while (port_accept(port))
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;
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port->has_connection = 0;
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}
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local_irq_restore(flags);
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}
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DECLARE_WORK(port_work, port_work_proc);
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static irqreturn_t port_interrupt(int irq, void *data)
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{
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struct port_list *port = data;
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port->has_connection = 1;
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schedule_work(&port_work);
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return IRQ_HANDLED;
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}
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void *port_data(int port_num)
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{
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struct list_head *ele;
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struct port_list *port;
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struct port_dev *dev = NULL;
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int fd;
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mutex_lock(&ports_mutex);
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list_for_each(ele, &ports) {
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port = list_entry(ele, struct port_list, list);
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if (port->port == port_num)
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goto found;
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}
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port = kmalloc(sizeof(struct port_list), GFP_KERNEL);
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if (port == NULL) {
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printk(KERN_ERR "Allocation of port list failed\n");
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goto out;
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}
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fd = port_listen_fd(port_num);
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if (fd < 0) {
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printk(KERN_ERR "binding to port %d failed, errno = %d\n",
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port_num, -fd);
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goto out_free;
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}
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if (um_request_irq(ACCEPT_IRQ, fd, IRQ_READ, port_interrupt,
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IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
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"port", port)) {
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printk(KERN_ERR "Failed to get IRQ for port %d\n", port_num);
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goto out_close;
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}
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*port = ((struct port_list)
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{ .list = LIST_HEAD_INIT(port->list),
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.wait_count = ATOMIC_INIT(0),
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.has_connection = 0,
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.port = port_num,
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.fd = fd,
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.pending = LIST_HEAD_INIT(port->pending),
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.connections = LIST_HEAD_INIT(port->connections) });
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spin_lock_init(&port->lock);
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init_completion(&port->done);
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list_add(&port->list, &ports);
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found:
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dev = kmalloc(sizeof(struct port_dev), GFP_KERNEL);
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if (dev == NULL) {
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printk(KERN_ERR "Allocation of port device entry failed\n");
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goto out;
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}
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*dev = ((struct port_dev) { .port = port,
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.helper_pid = -1,
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.telnetd_pid = -1 });
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goto out;
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out_close:
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os_close_file(fd);
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out_free:
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kfree(port);
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out:
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mutex_unlock(&ports_mutex);
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return dev;
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}
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int port_wait(void *data)
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{
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struct port_dev *dev = data;
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struct connection *conn;
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struct port_list *port = dev->port;
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int fd;
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atomic_inc(&port->wait_count);
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while (1) {
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fd = -ERESTARTSYS;
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if (wait_for_completion_interruptible(&port->done))
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goto out;
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spin_lock(&port->lock);
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conn = list_entry(port->connections.next, struct connection,
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list);
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list_del(&conn->list);
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spin_unlock(&port->lock);
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os_shutdown_socket(conn->socket[0], 1, 1);
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os_close_file(conn->socket[0]);
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os_shutdown_socket(conn->socket[1], 1, 1);
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os_close_file(conn->socket[1]);
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/* This is done here because freeing an IRQ can't be done
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* within the IRQ handler. So, pipe_interrupt always ups
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* the semaphore regardless of whether it got a successful
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* connection. Then we loop here throwing out failed
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* connections until a good one is found.
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*/
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free_irq(TELNETD_IRQ, conn);
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if (conn->fd >= 0)
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break;
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os_close_file(conn->fd);
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kfree(conn);
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}
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fd = conn->fd;
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dev->helper_pid = conn->helper_pid;
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dev->telnetd_pid = conn->telnetd_pid;
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kfree(conn);
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out:
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atomic_dec(&port->wait_count);
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return fd;
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}
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void port_remove_dev(void *d)
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{
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struct port_dev *dev = d;
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if (dev->helper_pid != -1)
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os_kill_process(dev->helper_pid, 0);
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if (dev->telnetd_pid != -1)
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os_kill_process(dev->telnetd_pid, 1);
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dev->helper_pid = -1;
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dev->telnetd_pid = -1;
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}
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void port_kern_free(void *d)
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{
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struct port_dev *dev = d;
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port_remove_dev(dev);
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kfree(dev);
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}
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static void free_port(void)
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{
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struct list_head *ele;
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struct port_list *port;
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list_for_each(ele, &ports) {
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port = list_entry(ele, struct port_list, list);
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free_irq_by_fd(port->fd);
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os_close_file(port->fd);
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}
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}
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__uml_exitcall(free_port);
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