pcmcia: use pccardd to handle eject, insert, suspend and resume requests
This avoids any sysfs-related deadlock (or lockdep warning), such as reported at http://lkml.org/lkml/2010/1/17/88 . Reported-by: Ming Lei <tom.leiming@gmail.com> Tested-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski
parent
cfe5d80951
commit
f971dbd5da
5 changed files with 83 additions and 141 deletions
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@ -505,7 +505,10 @@ static int socket_insert(struct pcmcia_socket *skt)
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dev_dbg(&skt->dev, "insert\n");
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mutex_lock(&skt->ops_mutex);
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WARN_ON(skt->state & SOCKET_INUSE);
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if (skt->state & SOCKET_INUSE) {
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mutex_unlock(&skt->ops_mutex);
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return -EINVAL;
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}
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skt->state |= SOCKET_INUSE;
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ret = socket_setup(skt, setup_delay);
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@ -682,16 +685,19 @@ static int pccardd(void *__skt)
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for (;;) {
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unsigned long flags;
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unsigned int events;
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unsigned int sysfs_events;
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set_current_state(TASK_INTERRUPTIBLE);
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spin_lock_irqsave(&skt->thread_lock, flags);
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events = skt->thread_events;
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skt->thread_events = 0;
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sysfs_events = skt->sysfs_events;
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skt->sysfs_events = 0;
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spin_unlock_irqrestore(&skt->thread_lock, flags);
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mutex_lock(&skt->skt_mutex);
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if (events) {
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mutex_lock(&skt->skt_mutex);
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if (events & SS_DETECT)
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socket_detect_change(skt);
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if (events & SS_BATDEAD)
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@ -700,10 +706,34 @@ static int pccardd(void *__skt)
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send_event(skt, CS_EVENT_BATTERY_LOW, CS_EVENT_PRI_LOW);
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if (events & SS_READY)
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send_event(skt, CS_EVENT_READY_CHANGE, CS_EVENT_PRI_LOW);
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mutex_unlock(&skt->skt_mutex);
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continue;
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}
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if (sysfs_events) {
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if (sysfs_events & PCMCIA_UEVENT_EJECT)
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socket_remove(skt);
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if (sysfs_events & PCMCIA_UEVENT_INSERT)
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socket_insert(skt);
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if ((sysfs_events & PCMCIA_UEVENT_RESUME) &&
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!(skt->state & SOCKET_CARDBUS)) {
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ret = socket_resume(skt);
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if (!ret && skt->callback)
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skt->callback->resume(skt);
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}
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if ((sysfs_events & PCMCIA_UEVENT_SUSPEND) &&
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!(skt->state & SOCKET_CARDBUS)) {
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if (skt->callback)
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ret = skt->callback->suspend(skt);
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else
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ret = 0;
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if (!ret)
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socket_suspend(skt);
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}
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}
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mutex_unlock(&skt->skt_mutex);
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if (events || sysfs_events)
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continue;
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if (kthread_should_stop())
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break;
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@ -745,6 +775,30 @@ void pcmcia_parse_events(struct pcmcia_socket *s, u_int events)
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} /* pcmcia_parse_events */
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EXPORT_SYMBOL(pcmcia_parse_events);
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/**
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* pcmcia_parse_uevents() - tell pccardd to issue manual commands
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* @s: the PCMCIA socket we wan't to command
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* @events: events to pass to pccardd
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*
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* userspace-issued insert, eject, suspend and resume commands must be
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* handled by pccardd to avoid any sysfs-related deadlocks. Valid events
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* are PCMCIA_UEVENT_EJECT (for eject), PCMCIA_UEVENT__INSERT (for insert),
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* PCMCIA_UEVENT_RESUME (for resume) and PCMCIA_UEVENT_SUSPEND (for suspend).
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*/
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void pcmcia_parse_uevents(struct pcmcia_socket *s, u_int events)
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{
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unsigned long flags;
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dev_dbg(&s->dev, "parse_uevents: events %08x\n", events);
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if (s->thread) {
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spin_lock_irqsave(&s->thread_lock, flags);
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s->sysfs_events |= events;
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spin_unlock_irqrestore(&s->thread_lock, flags);
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wake_up_process(s->thread);
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}
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}
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EXPORT_SYMBOL(pcmcia_parse_uevents);
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/* register pcmcia_callback */
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int pccard_register_pcmcia(struct pcmcia_socket *s, struct pcmcia_callback *c)
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@ -828,121 +882,6 @@ int pcmcia_reset_card(struct pcmcia_socket *skt)
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EXPORT_SYMBOL(pcmcia_reset_card);
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/* These shut down or wake up a socket. They are sort of user
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* initiated versions of the APM suspend and resume actions.
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*/
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int pcmcia_suspend_card(struct pcmcia_socket *skt)
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{
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int ret;
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dev_dbg(&skt->dev, "suspending socket\n");
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mutex_lock(&skt->skt_mutex);
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do {
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if (!(skt->state & SOCKET_PRESENT)) {
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ret = -ENODEV;
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break;
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}
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if (skt->state & SOCKET_CARDBUS) {
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ret = -EPERM;
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break;
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}
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if (skt->callback) {
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ret = skt->callback->suspend(skt);
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if (ret)
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break;
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}
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ret = socket_suspend(skt);
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} while (0);
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mutex_unlock(&skt->skt_mutex);
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return ret;
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} /* suspend_card */
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EXPORT_SYMBOL(pcmcia_suspend_card);
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int pcmcia_resume_card(struct pcmcia_socket *skt)
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{
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int ret;
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dev_dbg(&skt->dev, "waking up socket\n");
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mutex_lock(&skt->skt_mutex);
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do {
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if (!(skt->state & SOCKET_PRESENT)) {
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ret = -ENODEV;
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break;
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}
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if (skt->state & SOCKET_CARDBUS) {
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ret = -EPERM;
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break;
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}
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ret = socket_resume(skt);
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if (!ret && skt->callback)
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skt->callback->resume(skt);
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} while (0);
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mutex_unlock(&skt->skt_mutex);
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return ret;
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} /* resume_card */
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EXPORT_SYMBOL(pcmcia_resume_card);
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/* These handle user requests to eject or insert a card. */
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int pcmcia_eject_card(struct pcmcia_socket *skt)
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{
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int ret;
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dev_dbg(&skt->dev, "user eject request\n");
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mutex_lock(&skt->skt_mutex);
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do {
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if (!(skt->state & SOCKET_PRESENT)) {
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ret = -ENODEV;
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break;
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}
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ret = send_event(skt, CS_EVENT_EJECTION_REQUEST, CS_EVENT_PRI_LOW);
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if (ret != 0) {
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ret = -EINVAL;
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break;
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}
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socket_remove(skt);
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ret = 0;
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} while (0);
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mutex_unlock(&skt->skt_mutex);
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return ret;
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} /* eject_card */
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EXPORT_SYMBOL(pcmcia_eject_card);
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int pcmcia_insert_card(struct pcmcia_socket *skt)
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{
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int ret;
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dev_dbg(&skt->dev, "user insert request\n");
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mutex_lock(&skt->skt_mutex);
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do {
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if (skt->state & SOCKET_PRESENT) {
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ret = -EBUSY;
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break;
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}
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if (socket_insert(skt) == -ENODEV) {
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ret = -ENODEV;
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break;
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}
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ret = 0;
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} while (0);
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mutex_unlock(&skt->skt_mutex);
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return ret;
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} /* insert_card */
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EXPORT_SYMBOL(pcmcia_insert_card);
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static int pcmcia_socket_uevent(struct device *dev,
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struct kobj_uevent_env *env)
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{
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@ -124,11 +124,11 @@ extern struct class pcmcia_socket_class;
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int pccard_register_pcmcia(struct pcmcia_socket *s, struct pcmcia_callback *c);
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struct pcmcia_socket *pcmcia_get_socket_by_nr(unsigned int nr);
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int pcmcia_suspend_card(struct pcmcia_socket *skt);
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int pcmcia_resume_card(struct pcmcia_socket *skt);
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int pcmcia_eject_card(struct pcmcia_socket *skt);
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int pcmcia_insert_card(struct pcmcia_socket *skt);
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void pcmcia_parse_uevents(struct pcmcia_socket *socket, unsigned int events);
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#define PCMCIA_UEVENT_EJECT 0x0001
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#define PCMCIA_UEVENT_INSERT 0x0002
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#define PCMCIA_UEVENT_SUSPEND 0x0004
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#define PCMCIA_UEVENT_RESUME 0x0008
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struct pcmcia_socket *pcmcia_get_socket(struct pcmcia_socket *skt);
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void pcmcia_put_socket(struct pcmcia_socket *skt);
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@ -925,16 +925,16 @@ static int ds_ioctl(struct inode *inode, struct file *file,
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ret = pccard_validate_cis(s, &buf->cisinfo.Chains);
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break;
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case DS_SUSPEND_CARD:
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ret = pcmcia_suspend_card(s);
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_SUSPEND);
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break;
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case DS_RESUME_CARD:
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ret = pcmcia_resume_card(s);
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_RESUME);
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break;
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case DS_EJECT_CARD:
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err = pcmcia_eject_card(s);
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_EJECT);
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break;
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case DS_INSERT_CARD:
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err = pcmcia_insert_card(s);
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_INSERT);
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break;
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case DS_ACCESS_CONFIGURATION_REGISTER:
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if ((buf->conf_reg.Action == CS_WRITE) && !capable(CAP_SYS_ADMIN)) {
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@ -88,15 +88,14 @@ static DEVICE_ATTR(card_vcc, 0444, pccard_show_vcc, NULL);
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static ssize_t pccard_store_insert(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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ssize_t ret;
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struct pcmcia_socket *s = to_socket(dev);
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if (!count)
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return -EINVAL;
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ret = pcmcia_insert_card(s);
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_INSERT);
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return ret ? ret : count;
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return count;
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}
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static DEVICE_ATTR(card_insert, 0200, NULL, pccard_store_insert);
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@ -113,18 +112,22 @@ static ssize_t pccard_store_card_pm_state(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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ssize_t ret = -EINVAL;
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struct pcmcia_socket *s = to_socket(dev);
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ssize_t ret = count;
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if (!count)
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return -EINVAL;
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if (!(s->state & SOCKET_SUSPEND) && !strncmp(buf, "off", 3))
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ret = pcmcia_suspend_card(s);
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else if ((s->state & SOCKET_SUSPEND) && !strncmp(buf, "on", 2))
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ret = pcmcia_resume_card(s);
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if (!strncmp(buf, "off", 3))
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_SUSPEND);
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else {
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if (!strncmp(buf, "on", 2))
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_RESUME);
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else
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ret = -EINVAL;
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}
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return ret ? -ENODEV : count;
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return ret;
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}
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static DEVICE_ATTR(card_pm_state, 0644, pccard_show_card_pm_state, pccard_store_card_pm_state);
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@ -132,15 +135,14 @@ static ssize_t pccard_store_eject(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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ssize_t ret;
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struct pcmcia_socket *s = to_socket(dev);
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if (!count)
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return -EINVAL;
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ret = pcmcia_eject_card(s);
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pcmcia_parse_uevents(s, PCMCIA_UEVENT_EJECT);
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return ret ? ret : count;
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return count;
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}
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static DEVICE_ATTR(card_eject, 0200, NULL, pccard_store_eject);
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@ -200,13 +200,14 @@ struct pcmcia_socket {
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struct task_struct *thread;
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struct completion thread_done;
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unsigned int thread_events;
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unsigned int sysfs_events;
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/* For the non-trivial interaction between these locks,
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* see Documentation/pcmcia/locking.txt */
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struct mutex skt_mutex;
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struct mutex ops_mutex;
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/* protects thread_events */
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/* protects thread_events and sysfs_events */
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spinlock_t thread_lock;
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/* pcmcia (16-bit) */
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