[ 3.5.y.z extended stable ] Patch "sata_promise: fix hardreset lockdep error" has been added to staging queue

[Herton Ronaldo Krzesinski]

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

    sata_promise: fix hardreset lockdep error

to the linux-3.5.y-queue branch of the 3.5.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-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From 4b4ed1bb96c4b94b232e4b90c731187aeb0934ec Mon Sep 17 00:00:00 2001
From: Mikael Pettersson <mikpe at it.uu.se>
Date: Sun, 16 Sep 2012 20:53:43 +0200
Subject: [PATCH] sata_promise: fix hardreset lockdep error

commit 3100d49d3cd236443faae9d81137c81b22d36003 upstream.

sata_promise's pdc_hard_reset_port() needs to serialize because it
flips a port-specific bit in controller register that's shared by
all ports. The code takes the ata host lock for this, but that's
broken because an interrupt may arrive on our irq during the hard
reset sequence, and that too will take the ata host lock. With
lockdep enabled a big nasty warning is seen.

Fixed by adding private state to the ata host structure, containing
a second lock used only for serializing the hard reset sequences.
This eliminated the lockdep warnings both on my test rig and on
the original reporter's machine.

Signed-off-by: Mikael Pettersson <mikpe at it.uu.se>
Tested-by: Adko Branil <adkobranil at yahoo.com>
Signed-off-by: Jeff Garzik <jgarzik at redhat.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 drivers/ata/sata_promise.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/sata_promise.c b/drivers/ata/sata_promise.c
index 000fcc9..ef6e328 100644
--- a/drivers/ata/sata_promise.c
+++ b/drivers/ata/sata_promise.c
@@ -147,6 +147,10 @@ struct pdc_port_priv {
 	dma_addr_t		pkt_dma;
 };

+struct pdc_host_priv {
+	spinlock_t hard_reset_lock;
+};
+
 static int pdc_sata_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
 static int pdc_sata_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
 static int pdc_ata_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
@@ -801,9 +805,10 @@ static void pdc_hard_reset_port(struct ata_port *ap)
 	void __iomem *host_mmio = ap->host->iomap[PDC_MMIO_BAR];
 	void __iomem *pcictl_b1_mmio = host_mmio + PDC_PCI_CTL + 1;
 	unsigned int ata_no = pdc_ata_port_to_ata_no(ap);
+	struct pdc_host_priv *hpriv = ap->host->private_data;
 	u8 tmp;

-	spin_lock(&ap->host->lock);
+	spin_lock(&hpriv->hard_reset_lock);

 	tmp = readb(pcictl_b1_mmio);
 	tmp &= ~(0x10 << ata_no);
@@ -814,7 +819,7 @@ static void pdc_hard_reset_port(struct ata_port *ap)
 	writeb(tmp, pcictl_b1_mmio);
 	readb(pcictl_b1_mmio); /* flush */

-	spin_unlock(&ap->host->lock);
+	spin_unlock(&hpriv->hard_reset_lock);
 }

 static int pdc_sata_hardreset(struct ata_link *link, unsigned int *class,
@@ -1182,6 +1187,7 @@ static int pdc_ata_init_one(struct pci_dev *pdev,
 	const struct ata_port_info *pi = &pdc_port_info[ent->driver_data];
 	const struct ata_port_info *ppi[PDC_MAX_PORTS];
 	struct ata_host *host;
+	struct pdc_host_priv *hpriv;
 	void __iomem *host_mmio;
 	int n_ports, i, rc;
 	int is_sataii_tx4;
@@ -1218,6 +1224,11 @@ static int pdc_ata_init_one(struct pci_dev *pdev,
 		dev_err(&pdev->dev, "failed to allocate host\n");
 		return -ENOMEM;
 	}
+	hpriv = devm_kzalloc(&pdev->dev, sizeof *hpriv, GFP_KERNEL);
+	if (!hpriv)
+		return -ENOMEM;
+	spin_lock_init(&hpriv->hard_reset_lock);
+	host->private_data = hpriv;
 	host->iomap = pcim_iomap_table(pdev);

 	is_sataii_tx4 = pdc_is_sataii_tx4(pi->flags);
--
1.7.9.5