[PATCH 3.2 044/200] mmc: sdhci: fix lockdep error in tuning routine

[Ben Hutchings <ben@decadent.org.uk>]

3.2.56-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Aisheng Dong <b29396@freescale.com>

commit 2b35bd83467df6f8284b9148d6f768148c3a5e5f upstream.

The sdhci_execute_tuning routine gets lock separately by
disable_irq(host->irq);
spin_lock(&host->lock);
It will cause the following lockdep error message since the &host->lock
could also be got in irq context.
Use spin_lock_irqsave/spin_unlock_restore instead to get rid of
this error message.

[ INFO: inconsistent lock state ]
3.13.0-rc1+ #287 Not tainted
---------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
kworker/u2:1/33 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&(&host->lock)->rlock){?.-...}, at: [<8045f7f4>] sdhci_execute_tuning+0x4c/0x710
{IN-HARDIRQ-W} state was registered at:
  [<8005f030>] mark_lock+0x140/0x6ac
  [<80060760>] __lock_acquire+0xb30/0x1cbc
  [<800620d0>] lock_acquire+0x70/0x84
  [<8061d1c8>] _raw_spin_lock+0x30/0x40
  [<804605cc>] sdhci_irq+0x24/0xa68
  [<8006b1d4>] handle_irq_event_percpu+0x54/0x18c
  [<8006b350>] handle_irq_event+0x44/0x64
  [<8006e50c>] handle_fasteoi_irq+0xa0/0x170
  [<8006a8f0>] generic_handle_irq+0x30/0x44
  [<8000f238>] handle_IRQ+0x54/0xbc
  [<8000864c>] gic_handle_irq+0x30/0x64
  [<80013024>] __irq_svc+0x44/0x5c
  [<80329bf4>] dev_vprintk_emit+0x50/0x58
  [<80329c24>] dev_printk_emit+0x28/0x30
  [<80329fec>] __dev_printk+0x4c/0x90
  [<8032a180>] dev_err+0x3c/0x48
  [<802dd4f0>] _regulator_get+0x158/0x1cc
  [<802dd5b4>] regulator_get_optional+0x18/0x1c
  [<80461df4>] sdhci_add_host+0x42c/0xbd8
  [<80464820>] sdhci_esdhc_imx_probe+0x378/0x67c
  [<8032ee88>] platform_drv_probe+0x20/0x50
  [<8032d48c>] driver_probe_device+0x118/0x234
  [<8032d690>] __driver_attach+0x9c/0xa0
  [<8032b89c>] bus_for_each_dev+0x68/0x9c
  [<8032cf44>] driver_attach+0x20/0x28
  [<8032cbc8>] bus_add_driver+0x148/0x1f4
  [<8032dce0>] driver_register+0x80/0x100
  [<8032ee54>] __platform_driver_register+0x50/0x64
  [<8084b094>] sdhci_esdhc_imx_driver_init+0x18/0x20
  [<80008980>] do_one_initcall+0x108/0x16c
  [<8081cca4>] kernel_init_freeable+0x10c/0x1d0
  [<80611b28>] kernel_init+0x10/0x120
  [<8000e9c8>] ret_from_fork+0x14/0x2c
irq event stamp: 805
hardirqs last  enabled at (805): [<8061d43c>] _raw_spin_unlock_irqrestore+0x38/0x4c
hardirqs last disabled at (804): [<8061d2c8>] _raw_spin_lock_irqsave+0x24/0x54
softirqs last  enabled at (570): [<8002b824>] __do_softirq+0x1c4/0x290
softirqs last disabled at (561): [<8002bcf4>] irq_exit+0xb4/0x10c

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&host->lock)->rlock);
  <Interrupt>
    lock(&(&host->lock)->rlock);

 *** DEADLOCK ***

2 locks held by kworker/u2:1/33:
 #0:  (kmmcd){.+.+..}, at: [<8003db18>] process_one_work+0x128/0x468
 #1:  ((&(&host->detect)->work)){+.+...}, at: [<8003db18>] process_one_work+0x128/0x468

stack backtrace:
CPU: 0 PID: 33 Comm: kworker/u2:1 Not tainted 3.13.0-rc1+ #287
Workqueue: kmmcd mmc_rescan
Backtrace:
[<80012160>] (dump_backtrace+0x0/0x10c) from [<80012438>] (show_stack+0x18/0x1c)
 r6:bfad0900 r5:00000000 r4:8088ecc8 r3:bfad0900
[<80012420>] (show_stack+0x0/0x1c) from [<806169ec>] (dump_stack+0x84/0x9c)
[<80616968>] (dump_stack+0x0/0x9c) from [<806147b4>] (print_usage_bug+0x260/0x2d0)
 r5:8076ba88 r4:80977410
[<80614554>] (print_usage_bug+0x0/0x2d0) from [<8005f0d0>] (mark_lock+0x1e0/0x6ac)
 r9:8005e678 r8:00000000 r7:bfad0900 r6:00001015 r5:bfad0cd0
r4:00000002
[<8005eef0>] (mark_lock+0x0/0x6ac) from [<80060234>] (__lock_acquire+0x604/0x1cbc)
[<8005fc30>] (__lock_acquire+0x0/0x1cbc) from [<800620d0>] (lock_acquire+0x70/0x84)
[<80062060>] (lock_acquire+0x0/0x84) from [<8061d1c8>] (_raw_spin_lock+0x30/0x40)
 r7:00000000 r6:bfb63000 r5:00000000 r4:bfb60568
[<8061d198>] (_raw_spin_lock+0x0/0x40) from [<8045f7f4>] (sdhci_execute_tuning+0x4c/0x710)
 r4:bfb60000
[<8045f7a8>] (sdhci_execute_tuning+0x0/0x710) from [<80453454>] (mmc_sd_init_card+0x5f8/0x660)
[<80452e5c>] (mmc_sd_init_card+0x0/0x660) from [<80453748>] (mmc_attach_sd+0xb4/0x180)
 r9:bf92d400 r8:8065f364 r7:00061a80 r6:bfb60000 r5:8065f358
r4:bfb60000
[<80453694>] (mmc_attach_sd+0x0/0x180) from [<8044d9f8>] (mmc_rescan+0x284/0x2f0)
 r5:8065f358 r4:bfb602f8
[<8044d774>] (mmc_rescan+0x0/0x2f0) from [<8003db94>] (process_one_work+0x1a4/0x468)
 r8:00000000 r7:bfb55eb0 r6:bf80dc00 r5:bfb602f8 r4:bfb35980
r3:8044d774
[<8003d9f0>] (process_one_work+0x0/0x468) from [<8003e850>] (worker_thread+0x118/0x3e0)
[<8003e738>] (worker_thread+0x0/0x3e0) from [<80044de0>] (kthread+0xd4/0xf0)
[<80044d0c>] (kthread+0x0/0xf0) from [<8000e9c8>] (ret_from_fork+0x14/0x2c)
 r7:00000000 r6:00000000 r5:80044d0c r4:bfb37b40

Signed-off-by: Dong Aisheng <b29396@freescale.com>
Signed-off-by: Chris Ball <chris@printf.net>
[bwh: Backported to 3.2:
 - Adjust context
 - There's no platform_execute_tuning hook]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/mmc/host/sdhci.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1670,12 +1670,12 @@ static int sdhci_execute_tuning(struct m
 	int tuning_loop_counter = MAX_TUNING_LOOP;
 	unsigned long timeout;
 	int err = 0;
+	unsigned long flags;
 
 	host = mmc_priv(mmc);
 
 	sdhci_runtime_pm_get(host);
-	disable_irq(host->irq);
-	spin_lock(&host->lock);
+	spin_lock_irqsave(&host->lock, flags);
 
 	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
 
@@ -1689,8 +1689,7 @@ static int sdhci_execute_tuning(struct m
 	    (host->flags & SDHCI_SDR50_NEEDS_TUNING)))
 		ctrl |= SDHCI_CTRL_EXEC_TUNING;
 	else {
-		spin_unlock(&host->lock);
-		enable_irq(host->irq);
+		spin_unlock_irqrestore(&host->lock, flags);
 		sdhci_runtime_pm_put(host);
 		return 0;
 	}
@@ -1752,15 +1751,12 @@ static int sdhci_execute_tuning(struct m
 		host->cmd = NULL;
 		host->mrq = NULL;
 
-		spin_unlock(&host->lock);
-		enable_irq(host->irq);
-
+		spin_unlock_irqrestore(&host->lock, flags);
 		/* Wait for Buffer Read Ready interrupt */
 		wait_event_interruptible_timeout(host->buf_ready_int,
 					(host->tuning_done == 1),
 					msecs_to_jiffies(50));
-		disable_irq(host->irq);
-		spin_lock(&host->lock);
+		spin_lock_irqsave(&host->lock, flags);
 
 		if (!host->tuning_done) {
 			pr_info(DRIVER_NAME ": Timeout waiting for "
@@ -1833,8 +1829,7 @@ out:
 		err = 0;
 
 	sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
-	spin_unlock(&host->lock);
-	enable_irq(host->irq);
+	spin_unlock_irqrestore(&host->lock, flags);
 	sdhci_runtime_pm_put(host);
 
 	return err;