From: Paul Mackerras Date: Thu, 13 Dec 2007 04:11:22 +0000 (+1100) Subject: [POWERPC] Convert adb.c to use kthread API and not spin on ADB requests X-Git-Tag: v2.6.25-rc1~1131^2~280 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=c61dace9a10a4bc54c764f9f490994a9d7852859;p=linux-2.6-omap-h63xx.git [POWERPC] Convert adb.c to use kthread API and not spin on ADB requests This converts adb.c to use the kthread API. It also changes adb_request so that if the ADBREQ_SYNC flag is specified, we now sleep waiting for the request to finish using an on-stack completion rather than spinning. To implement this, we now require that if the ADBREQ_SYNC flag is set, the `done' parameter must be NULL. All of the existing callers of adb_request that pass ADBREQ_SYNC appear to be in process context and have done == NULL. Doing this allows us to get rid of an awful hack in adb_request() where we used to test whether the request was coming from the adb probe task and use a completion if it was, and otherwise spin. This also gets rid of a static request block that was used if the req parameter to adb_request was NULL. None of the callers do that any more, so the static request block is no longer necessary. Signed-off-by: Paul Mackerras --- diff --git a/drivers/macintosh/adb.c b/drivers/macintosh/adb.c index 7b892f4a8e8..5ae28f076d2 100644 --- a/drivers/macintosh/adb.c +++ b/drivers/macintosh/adb.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -82,9 +83,7 @@ struct adb_driver *adb_controller; BLOCKING_NOTIFIER_HEAD(adb_client_list); static int adb_got_sleep; static int adb_inited; -static pid_t adb_probe_task_pid; static DECLARE_MUTEX(adb_probe_mutex); -static struct completion adb_probe_task_comp; static int sleepy_trackpad; static int autopoll_devs; int __adb_probe_sync; @@ -126,16 +125,6 @@ static void printADBreply(struct adb_request *req) } #endif - -static __inline__ void adb_wait_ms(unsigned int ms) -{ - if (current->pid && adb_probe_task_pid && - adb_probe_task_pid == current->pid) - msleep(ms); - else - mdelay(ms); -} - static int adb_scan_bus(void) { int i, highFree=0, noMovement; @@ -240,13 +229,10 @@ static int adb_scan_bus(void) static int adb_probe_task(void *x) { - strcpy(current->comm, "kadbprobe"); - printk(KERN_INFO "adb: starting probe task...\n"); do_adb_reset_bus(); printk(KERN_INFO "adb: finished probe task...\n"); - adb_probe_task_pid = 0; up(&adb_probe_mutex); return 0; @@ -255,7 +241,7 @@ adb_probe_task(void *x) static void __adb_probe_task(struct work_struct *bullshit) { - adb_probe_task_pid = kernel_thread(adb_probe_task, NULL, SIGCHLD | CLONE_KERNEL); + kthread_run(adb_probe_task, NULL, "kadbprobe"); } static DECLARE_WORK(adb_reset_work, __adb_probe_task); @@ -341,7 +327,6 @@ int __init adb_init(void) sleepy_trackpad = 1; #endif /* CONFIG_PPC */ - init_completion(&adb_probe_task_comp); adbdev_init(); adb_reset_bus(); } @@ -366,7 +351,7 @@ do_adb_reset_bus(void) if (sleepy_trackpad) { /* Let the trackpad settle down */ - adb_wait_ms(500); + msleep(500); } down(&adb_handler_sem); @@ -382,7 +367,7 @@ do_adb_reset_bus(void) if (sleepy_trackpad) { /* Let the trackpad settle down */ - adb_wait_ms(1500); + msleep(1500); } if (!ret) { @@ -406,41 +391,27 @@ adb_poll(void) adb_controller->poll(); } -static void -adb_probe_wakeup(struct adb_request *req) +static void adb_sync_req_done(struct adb_request *req) { - complete(&adb_probe_task_comp); -} + struct completion *comp = req->arg; -/* Static request used during probe */ -static struct adb_request adb_sreq; -static unsigned long adb_sreq_lock; // Use semaphore ! */ + complete(comp); +} int adb_request(struct adb_request *req, void (*done)(struct adb_request *), int flags, int nbytes, ...) { va_list list; - int i, use_sreq; + int i; int rc; + struct completion comp; if ((adb_controller == NULL) || (adb_controller->send_request == NULL)) return -ENXIO; if (nbytes < 1) return -EINVAL; - if (req == NULL && (flags & ADBREQ_NOSEND)) - return -EINVAL; - - if (req == NULL) { - if (test_and_set_bit(0,&adb_sreq_lock)) { - printk("adb.c: Warning: contention on static request !\n"); - return -EPERM; - } - req = &adb_sreq; - flags |= ADBREQ_SYNC; - use_sreq = 1; - } else - use_sreq = 0; + req->nbytes = nbytes+1; req->done = done; req->reply_expected = flags & ADBREQ_REPLY; @@ -453,25 +424,18 @@ adb_request(struct adb_request *req, void (*done)(struct adb_request *), if (flags & ADBREQ_NOSEND) return 0; - /* Synchronous requests send from the probe thread cause it to - * block. Beware that the "done" callback will be overriden ! - */ - if ((flags & ADBREQ_SYNC) && - (current->pid && adb_probe_task_pid && - adb_probe_task_pid == current->pid)) { - req->done = adb_probe_wakeup; - rc = adb_controller->send_request(req, 0); - if (rc || req->complete) - goto bail; - wait_for_completion(&adb_probe_task_comp); - rc = 0; - goto bail; + /* Synchronous requests block using an on-stack completion */ + if (flags & ADBREQ_SYNC) { + WARN_ON(done); + req->done = adb_sync_req_done; + req->arg = ∁ + init_completion(&comp); } - rc = adb_controller->send_request(req, flags & ADBREQ_SYNC); -bail: - if (use_sreq) - clear_bit(0, &adb_sreq_lock); + rc = adb_controller->send_request(req, 0); + + if ((flags & ADBREQ_SYNC) && !rc && !req->complete) + wait_for_completion(&comp); return rc; }