[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 <paulus@samba.org>
diff --git a/drivers/macintosh/adb.c b/drivers/macintosh/adb.c
index 7b892f4..5ae28f0 100644
--- a/drivers/macintosh/adb.c
+++ b/drivers/macintosh/adb.c
@@ -35,6 +35,7 @@
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/device.h>
+#include <linux/kthread.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
@@ -82,9 +83,7 @@
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 @@
}
#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_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 @@
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 @@
sleepy_trackpad = 1;
#endif /* CONFIG_PPC */
- init_completion(&adb_probe_task_comp);
adbdev_init();
adb_reset_bus();
}
@@ -366,7 +351,7 @@
if (sleepy_trackpad) {
/* Let the trackpad settle down */
- adb_wait_ms(500);
+ msleep(500);
}
down(&adb_handler_sem);
@@ -382,7 +367,7 @@
if (sleepy_trackpad) {
/* Let the trackpad settle down */
- adb_wait_ms(1500);
+ msleep(1500);
}
if (!ret) {
@@ -406,41 +391,27 @@
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 @@
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;
}