From: James Leddy <james.leddy@redhat.com>
Date: Thu, 14 Oct 2010 18:54:44 -0400
Subject: [ide] atiixp: fix locking hang in ide layer ATIIXP driver
Message-id: <20101014185442.GA28743@xander.lga.redhat.com>
Patchwork-id: 28752
O-Subject: [RHEL5.6 PATCH] atiixp: Old drivers/ide layer driver for the ATIIXP
	hang fix
Bugzilla: 586482
RH-Acked-by: David Milburn <dmilburn@redhat.com>
RH-Acked-by: Bryn M. Reeves <bmr@redhat.com>
RH-Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>

Cherry pick of 6c5f8cc33eb2e10b6ab788bbe259fc142a068627 from upstream

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=6c5f8cc33eb2e10b6ab788bbe259fc142a068627

The customer has tested and verified that this patch fixes the issue.
They have not seen any other problems in their testing.

The following is the original commit message:

When the old IDE layer calls into methods in the driver during error
handling it is essentially random whether ide_lock is already held.  This
causes a deadlock in the atiixp driver which also uses ide_lock internally
for locking.

Switch to a private lock instead.

[akpm@osl.org: cleanup]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/ide/pci/atiixp.c b/drivers/ide/pci/atiixp.c
index 003a6e3..d4b9e6a 100644
--- a/drivers/ide/pci/atiixp.c
+++ b/drivers/ide/pci/atiixp.c
@@ -46,6 +46,8 @@ static atiixp_ide_timing mdma_timing[] = {
 
 static int save_mdma_mode[4];
 
+static DEFINE_SPINLOCK(atiixp_lock);
+
 /**
  *	atiixp_ratemask		-	compute rate mask for ATIIXP IDE
  *	@drive: IDE drive to compute for
@@ -105,7 +107,7 @@ static int atiixp_ide_dma_host_on(ide_drive_t *drive)
 	unsigned long flags;
 	u16 tmp16;
 
-	spin_lock_irqsave(&ide_lock, flags);
+	spin_lock_irqsave(&atiixp_lock, flags);
 
 	pci_read_config_word(dev, ATIIXP_IDE_UDMA_CONTROL, &tmp16);
 	if (save_mdma_mode[drive->dn])
@@ -114,7 +116,7 @@ static int atiixp_ide_dma_host_on(ide_drive_t *drive)
 		tmp16 |= (1 << drive->dn);
 	pci_write_config_word(dev, ATIIXP_IDE_UDMA_CONTROL, tmp16);
 
-	spin_unlock_irqrestore(&ide_lock, flags);
+	spin_unlock_irqrestore(&atiixp_lock, flags);
 
 	return __ide_dma_host_on(drive);
 }
@@ -125,13 +127,13 @@ static int atiixp_ide_dma_host_off(ide_drive_t *drive)
 	unsigned long flags;
 	u16 tmp16;
 
-	spin_lock_irqsave(&ide_lock, flags);
+	spin_lock_irqsave(&atiixp_lock, flags);
 
 	pci_read_config_word(dev, ATIIXP_IDE_UDMA_CONTROL, &tmp16);
 	tmp16 &= ~(1 << drive->dn);
 	pci_write_config_word(dev, ATIIXP_IDE_UDMA_CONTROL, tmp16);
 
-	spin_unlock_irqrestore(&ide_lock, flags);
+	spin_unlock_irqrestore(&atiixp_lock, flags);
 
 	return __ide_dma_host_off(drive);
 }
@@ -152,7 +154,7 @@ static void atiixp_tuneproc(ide_drive_t *drive, u8 pio)
 	u32 pio_timing_data;
 	u16 pio_mode_data;
 
-	spin_lock_irqsave(&ide_lock, flags);
+	spin_lock_irqsave(&atiixp_lock, flags);
 
 	pci_read_config_word(dev, ATIIXP_IDE_PIO_MODE, &pio_mode_data);
 	pio_mode_data &= ~(0x07 << (drive->dn * 4));
@@ -165,7 +167,7 @@ static void atiixp_tuneproc(ide_drive_t *drive, u8 pio)
 		 (pio_timing[pio].command_width << (timing_shift + 4));
 	pci_write_config_dword(dev, ATIIXP_IDE_PIO_TIMING, pio_timing_data);
 
-	spin_unlock_irqrestore(&ide_lock, flags);
+	spin_unlock_irqrestore(&atiixp_lock, flags);
 }
 
 /**
@@ -189,7 +191,7 @@ static int atiixp_speedproc(ide_drive_t *drive, u8 xferspeed)
 
 	speed = ide_rate_filter(atiixp_ratemask(drive), xferspeed);
 
-	spin_lock_irqsave(&ide_lock, flags);
+	spin_lock_irqsave(&atiixp_lock, flags);
 
 	save_mdma_mode[drive->dn] = 0;
 	if (speed >= XFER_UDMA_0) {
@@ -208,7 +210,7 @@ static int atiixp_speedproc(ide_drive_t *drive, u8 xferspeed)
 		}
 	}
 
-	spin_unlock_irqrestore(&ide_lock, flags);
+	spin_unlock_irqrestore(&atiixp_lock, flags);
 
 	if (speed >= XFER_SW_DMA_0)
 		pio = atiixp_dma_2_pio(speed);