b43: avoid unregistering device objects during suspend

Modify the b43 driver to avoid deadlocking suspend and resume, which happens
as a result of attempting to unregister device objects locked by the PM core
during suspend/resume cycles.  Also, make it use a suspend-safe method of
unregistering device object in the resume error path.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Michael Buesch <mb@bu3sch.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 21 insertions, 10 deletions

diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
index 32a24f5c4fa6..08a011f0834a 100644
--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -724,6 +724,7 @@ struct b43_wldev {
         bool short_preamble;    /* TRUE, if short preamble is enabled. */
         bool short_slot;        /* TRUE, if short slot timing is enabled. */
         bool radio_hw_enable;   /* saved state of radio hardware enabled state */
+        bool suspend_in_progress;       /* TRUE, if we are in a suspend/resume cycle */
 
         /* PHY/Radio device. */
         struct b43_phy phy;
diff --git a/drivers/net/wireless/b43/leds.c b/drivers/net/wireless/b43/leds.c
index 4b590d8c65ff..0908335892db 100644
--- a/drivers/net/wireless/b43/leds.c
+++ b/drivers/net/wireless/b43/leds.c
@@ -116,7 +116,10 @@ static void b43_unregister_led(struct b43_led *led)
 {
         if (!led->dev)
                 return;
-        led_classdev_unregister(&led->led_dev);
+        if (led->dev->suspend_in_progress)
+                led_classdev_unregister_suspended(&led->led_dev);
+        else
+                led_classdev_unregister(&led->led_dev);
         b43_led_turn_off(led->dev, led->index, led->activelow);
         led->dev = NULL;
 }
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 6faa57a2242e..ef65c41af00f 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -2555,10 +2555,10 @@ static int b43_rng_read(struct hwrng *rng, u32 * data)
         return (sizeof(u16));
 }
 
-static void b43_rng_exit(struct b43_wl *wl)
+static void b43_rng_exit(struct b43_wl *wl, bool suspended)
 {
         if (wl->rng_initialized)
-                hwrng_unregister(&wl->rng);
+                __hwrng_unregister(&wl->rng, suspended);
 }
 
 static int b43_rng_init(struct b43_wl *wl)
@@ -3418,8 +3418,10 @@ static void b43_wireless_core_exit(struct b43_wldev *dev)
         macctl |= B43_MACCTL_PSM_JMP0;
         b43_write32(dev, B43_MMIO_MACCTL, macctl);
 
-        b43_leds_exit(dev);
-        b43_rng_exit(dev->wl);
+        if (!dev->suspend_in_progress) {
+                b43_leds_exit(dev);
+                b43_rng_exit(dev->wl, false);
+        }
         b43_dma_free(dev);
         b43_chip_exit(dev);
         b43_radio_turn_off(dev, 1);
@@ -3535,11 +3537,13 @@ static int b43_wireless_core_init(struct b43_wldev *dev)
         ssb_bus_powerup(bus, 1);        /* Enable dynamic PCTL */
         b43_upload_card_macaddress(dev);
         b43_security_init(dev);
-        b43_rng_init(wl);
+        if (!dev->suspend_in_progress)
+                b43_rng_init(wl);
 
         b43_set_status(dev, B43_STAT_INITIALIZED);
 
-        b43_leds_init(dev);
+        if (!dev->suspend_in_progress)
+                b43_leds_init(dev);
 out:
         return err;
 
@@ -4136,6 +4140,7 @@ static int b43_suspend(struct ssb_device *dev, pm_message_t state)
         b43dbg(wl, "Suspending...\n");
 
         mutex_lock(&wl->mutex);
+        wldev->suspend_in_progress = true;
         wldev->suspend_init_status = b43_status(wldev);
         if (wldev->suspend_init_status >= B43_STAT_STARTED)
                 b43_wireless_core_stop(wldev);
@@ -4167,15 +4172,17 @@ static int b43_resume(struct ssb_device *dev)
         if (wldev->suspend_init_status >= B43_STAT_STARTED) {
                 err = b43_wireless_core_start(wldev);
                 if (err) {
+                        b43_leds_exit(wldev);
+                        b43_rng_exit(wldev->wl, true);
                         b43_wireless_core_exit(wldev);
                         b43err(wl, "Resume failed at core start\n");
                         goto out;
                 }
         }
-        mutex_unlock(&wl->mutex);
-
         b43dbg(wl, "Device resumed.\n");
-      out:
+ out:
+        wldev->suspend_in_progress = false;
+        mutex_unlock(&wl->mutex);
         return err;
 }