[ 3.8.y.z extended stable ] Patch "sata_fsl: save irqs while coalescing" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Thu Aug 29 23:47:22 UTC 2013


This is a note to let you know that I have just added a patch titled

    sata_fsl: save irqs while coalescing

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.8.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 57d00b1183fee6fd5aba71b34d3b03cc8a78f56f Mon Sep 17 00:00:00 2001
From: Anthony Foiani <anthony.foiani at gmail.com>
Date: Mon, 19 Aug 2013 19:20:30 -0600
Subject: sata_fsl: save irqs while coalescing

commit 99bbdfa6bdcb4bdf5be914a48e9b46941bf30819 upstream.

Before this patch, I was seeing the following lockdep splat on my
MPC8315 (PPC32) target:

  [    9.086051] =================================
  [    9.090393] [ INFO: inconsistent lock state ]
  [    9.094744] 3.9.7-ajf-gc39503d #1 Not tainted
  [    9.099087] ---------------------------------
  [    9.103432] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
  [    9.109431] scsi_eh_1/39 [HC1[1]:SC0[0]:HE0:SE1] takes:
  [    9.114642]  (&(&host->lock)->rlock){?.+...}, at: [<c02f4168>] sata_fsl_interrupt+0x50/0x250
  [    9.123137] {HARDIRQ-ON-W} state was registered at:
  [    9.128004]   [<c006cdb8>] lock_acquire+0x90/0xf4
  [    9.132737]   [<c043ef04>] _raw_spin_lock+0x34/0x4c
  [    9.137645]   [<c02f3560>] fsl_sata_set_irq_coalescing+0x68/0x100
  [    9.143750]   [<c02f36a0>] sata_fsl_init_controller+0xa8/0xc0
  [    9.149505]   [<c02f3f10>] sata_fsl_probe+0x17c/0x2e8
  [    9.154568]   [<c02acc90>] driver_probe_device+0x90/0x248
  [    9.159987]   [<c02acf0c>] __driver_attach+0xc4/0xc8
  [    9.164964]   [<c02aae74>] bus_for_each_dev+0x5c/0xa8
  [    9.170028]   [<c02ac218>] bus_add_driver+0x100/0x26c
  [    9.175091]   [<c02ad638>] driver_register+0x88/0x198
  [    9.180155]   [<c0003a24>] do_one_initcall+0x58/0x1b4
  [    9.185226]   [<c05aeeac>] kernel_init_freeable+0x118/0x1c0
  [    9.190823]   [<c0004110>] kernel_init+0x18/0x108
  [    9.195542]   [<c000f6b8>] ret_from_kernel_thread+0x64/0x6c
  [    9.201142] irq event stamp: 160
  [    9.204366] hardirqs last  enabled at (159): [<c043f778>] _raw_spin_unlock_irq+0x30/0x50
  [    9.212469] hardirqs last disabled at (160): [<c000f414>] reenable_mmu+0x30/0x88
  [    9.219867] softirqs last  enabled at (144): [<c002ae5c>] __do_softirq+0x168/0x218
  [    9.227435] softirqs last disabled at (137): [<c002b0d4>] irq_exit+0xa8/0xb4
  [    9.234481]
  [    9.234481] other info that might help us debug this:
  [    9.240995]  Possible unsafe locking scenario:
  [    9.240995]
  [    9.246898]        CPU0
  [    9.249337]        ----
  [    9.251776]   lock(&(&host->lock)->rlock);
  [    9.255878]   <Interrupt>
  [    9.258492]     lock(&(&host->lock)->rlock);
  [    9.262765]
  [    9.262765]  *** DEADLOCK ***
  [    9.262765]
  [    9.268684] no locks held by scsi_eh_1/39.
  [    9.272767]
  [    9.272767] stack backtrace:
  [    9.277117] Call Trace:
  [    9.279589] [cfff9da0] [c0008504] show_stack+0x48/0x150 (unreliable)
  [    9.285972] [cfff9de0] [c0447d5c] print_usage_bug.part.35+0x268/0x27c
  [    9.292425] [cfff9e10] [c006ace4] mark_lock+0x2ac/0x658
  [    9.297660] [cfff9e40] [c006b7e4] __lock_acquire+0x754/0x1840
  [    9.303414] [cfff9ee0] [c006cdb8] lock_acquire+0x90/0xf4
  [    9.308745] [cfff9f20] [c043ef04] _raw_spin_lock+0x34/0x4c
  [    9.314250] [cfff9f30] [c02f4168] sata_fsl_interrupt+0x50/0x250
  [    9.320187] [cfff9f70] [c0079ff0] handle_irq_event_percpu+0x90/0x254
  [    9.326547] [cfff9fc0] [c007a1fc] handle_irq_event+0x48/0x78
  [    9.332220] [cfff9fe0] [c007c95c] handle_level_irq+0x9c/0x104
  [    9.337981] [cfff9ff0] [c000d978] call_handle_irq+0x18/0x28
  [    9.343568] [cc7139f0] [c000608c] do_IRQ+0xf0/0x1a8
  [    9.348464] [cc713a20] [c000fc8c] ret_from_except+0x0/0x14
  [    9.353983] --- Exception: 501 at _raw_spin_unlock_irq+0x40/0x50
  [    9.353983]     LR = _raw_spin_unlock_irq+0x30/0x50
  [    9.364839] [cc713af0] [c043db10] wait_for_common+0xac/0x188
  [    9.370513] [cc713b30] [c02ddee4] ata_exec_internal_sg+0x2b0/0x4f0
  [    9.376699] [cc713be0] [c02de18c] ata_exec_internal+0x68/0xa8
  [    9.382454] [cc713c20] [c02de4b8] ata_dev_read_id+0x158/0x594
  [    9.388205] [cc713ca0] [c02ec244] ata_eh_recover+0xd88/0x13d0
  [    9.393962] [cc713d20] [c02f2520] sata_pmp_error_handler+0xc0/0x8ac
  [    9.400234] [cc713dd0] [c02ecdc8] ata_scsi_port_error_handler+0x464/0x5e8
  [    9.407023] [cc713e10] [c02ecfd0] ata_scsi_error+0x84/0xb8
  [    9.412528] [cc713e40] [c02c4974] scsi_error_handler+0xd8/0x47c
  [    9.418457] [cc713eb0] [c004737c] kthread+0xa8/0xac
  [    9.423355] [cc713f40] [c000f6b8] ret_from_kernel_thread+0x64/0x6c

This fix was suggested by Bhushan Bharat <R65777 at freescale.com>, and
was discussed in email at:

  http://linuxppc.10917.n7.nabble.com/MPC8315-reboot-failure-lockdep-splat-possibly-related-tp75162.html

Same patch successfully tested with 3.9.7.  linux-next compiled but
not tested on hardware.

This patch is based off linux-next tag next-20130819
(which is commit 66a01bae29d11916c09f9f5a937cafe7d402e4a5 )

Signed-off-by: Anthony Foiani <anthony.foiani at gmail.com>
Signed-off-by: Tejun Heo <tj at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/ata/sata_fsl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/sata_fsl.c b/drivers/ata/sata_fsl.c
index 124b2c1..34fa7c6 100644
--- a/drivers/ata/sata_fsl.c
+++ b/drivers/ata/sata_fsl.c
@@ -292,6 +292,7 @@ static void fsl_sata_set_irq_coalescing(struct ata_host *host,
 {
 	struct sata_fsl_host_priv *host_priv = host->private_data;
 	void __iomem *hcr_base = host_priv->hcr_base;
+	unsigned long flags;

 	if (count > ICC_MAX_INT_COUNT_THRESHOLD)
 		count = ICC_MAX_INT_COUNT_THRESHOLD;
@@ -304,12 +305,12 @@ static void fsl_sata_set_irq_coalescing(struct ata_host *host,
 			(count > ICC_MIN_INT_COUNT_THRESHOLD))
 		ticks = ICC_SAFE_INT_TICKS;

-	spin_lock(&host->lock);
+	spin_lock_irqsave(&host->lock, flags);
 	iowrite32((count << 24 | ticks), hcr_base + ICC);

 	intr_coalescing_count = count;
 	intr_coalescing_ticks = ticks;
-	spin_unlock(&host->lock);
+	spin_unlock_irqrestore(&host->lock, flags);

 	DPRINTK("intrrupt coalescing, count = 0x%x, ticks = %x\n",
 			intr_coalescing_count, intr_coalescing_ticks);
--
1.8.1.2





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