Patchwork [#upstream-fixes] ahci: fix module refcount breakage introduced by libahci split

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Submitter Tejun Heo
Date Sept. 21, 2010, 7:25 a.m.
Message ID <4C985DFC.7020203@gmail.com>
Download mbox | patch
Permalink /patch/65277/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

Tejun Heo - Sept. 21, 2010, 7:25 a.m.
libata depends on scsi_host_template for module reference counting and
sht's should be owned by each low level driver.  During libahci split,
the sht was left with libahci.ko leaving the actual low level drivers
not reference counted.  This made ahci and ahci_platform always
unloadable even while they're being actively used.

Fix it by defining AHCI_SHT() macro in ahci.h and defining a sht for
each low level ahci driver.

stable: only applicable to 2.6.35.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Cc: stable@kernel.org
---
Michael, thanks a lot for spotting it and bearing with me.

 drivers/ata/ahci.c          |    4 ++++
 drivers/ata/ahci.h          |   12 +++++++++++-
 drivers/ata/ahci_platform.c |    6 +++++-
 drivers/ata/libahci.c       |   16 ++++------------
 4 files changed, 24 insertions(+), 14 deletions(-)

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Michael Tokarev - Sept. 21, 2010, 7:32 a.m.
21.09.2010 11:25, Tejun Heo wrote:
> libata depends on scsi_host_template for module reference counting and
> sht's should be owned by each low level driver.  During libahci split,
> the sht was left with libahci.ko leaving the actual low level drivers
> not reference counted.  This made ahci and ahci_platform always
> unloadable even while they're being actively used.
> 
> Fix it by defining AHCI_SHT() macro in ahci.h and defining a sht for
> each low level ahci driver.
> 
> stable: only applicable to 2.6.35.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Reported-by: Michael Tokarev <mjt@tls.msk.ru>
> Cc: stable@kernel.org
> ---
> Michael, thanks a lot for spotting it and bearing with me.

Um.  All thanks goes to Pedro Francisco please, not to me -
I just verified your patch on my system, it was Pedro who spotted
and reported this.  You may add my

 Tested-Off-By: Michael Tokarev <mjt@tls.msk.ru>

, but not Reported-by... please ;)

Thanks!

/mjt
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Tejun Heo - Sept. 21, 2010, 8:17 a.m.
On 09/21/2010 09:32 AM, Michael Tokarev wrote:
> 21.09.2010 11:25, Tejun Heo wrote:
>> libata depends on scsi_host_template for module reference counting and
>> sht's should be owned by each low level driver.  During libahci split,
>> the sht was left with libahci.ko leaving the actual low level drivers
>> not reference counted.  This made ahci and ahci_platform always
>> unloadable even while they're being actively used.
>>
>> Fix it by defining AHCI_SHT() macro in ahci.h and defining a sht for
>> each low level ahci driver.
>>
>> stable: only applicable to 2.6.35.
>>
>> Signed-off-by: Tejun Heo <tj@kernel.org>
>> Reported-by: Michael Tokarev <mjt@tls.msk.ru>
>> Cc: stable@kernel.org
>> ---
>> Michael, thanks a lot for spotting it and bearing with me.
> Um.  All thanks goes to Pedro Francisco please, not to me -
> I just verified your patch on my system, it was Pedro who spotted
> and reported this.  You may add my
> 
>  Tested-Off-By: Michael Tokarev <mjt@tls.msk.ru>
> 
> , but not Reported-by... please ;)

Oh, right.  Jeff, can you please adjust tags to

  Reported-by: Pedro Francisco <pedrogfrancisco@gmail.com>
  Tested-by: Michael Tokarev <mjt@tls.msk.ru>

Thanks.

Patch

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index ff1c945..99d0e5a 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -90,6 +90,10 @@  static int ahci_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg);
 static int ahci_pci_device_resume(struct pci_dev *pdev);
 #endif

+static struct scsi_host_template ahci_sht = {
+	AHCI_SHT("ahci"),
+};
+
 static struct ata_port_operations ahci_vt8251_ops = {
 	.inherits		= &ahci_ops,
 	.hardreset		= ahci_vt8251_hardreset,
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 474427b..e5fdeeb 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -298,7 +298,17 @@  struct ahci_host_priv {

 extern int ahci_ignore_sss;

-extern struct scsi_host_template ahci_sht;
+extern struct device_attribute *ahci_shost_attrs[];
+extern struct device_attribute *ahci_sdev_attrs[];
+
+#define AHCI_SHT(drv_name)						\
+	ATA_NCQ_SHT(drv_name),						\
+	.can_queue		= AHCI_MAX_CMDS - 1,			\
+	.sg_tablesize		= AHCI_MAX_SG,				\
+	.dma_boundary		= AHCI_DMA_BOUNDARY,			\
+	.shost_attrs		= ahci_shost_attrs,			\
+	.sdev_attrs		= ahci_sdev_attrs
+
 extern struct ata_port_operations ahci_ops;

 void ahci_save_initial_config(struct device *dev,
diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index 4e97f33..84b6432 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -23,6 +23,10 @@ 
 #include <linux/ahci_platform.h>
 #include "ahci.h"

+static struct scsi_host_template ahci_platform_sht = {
+	AHCI_SHT("ahci_platform"),
+};
+
 static int __init ahci_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -145,7 +149,7 @@  static int __init ahci_probe(struct platform_device *pdev)
 	ahci_print_info(host, "platform");

 	rc = ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
-			       &ahci_sht);
+			       &ahci_platform_sht);
 	if (rc)
 		goto err0;

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 68dc678..8eea309 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -121,7 +121,7 @@  static DEVICE_ATTR(ahci_port_cmd, S_IRUGO, ahci_show_port_cmd, NULL);
 static DEVICE_ATTR(em_buffer, S_IWUSR | S_IRUGO,
 		   ahci_read_em_buffer, ahci_store_em_buffer);

-static struct device_attribute *ahci_shost_attrs[] = {
+struct device_attribute *ahci_shost_attrs[] = {
 	&dev_attr_link_power_management_policy,
 	&dev_attr_em_message_type,
 	&dev_attr_em_message,
@@ -132,22 +132,14 @@  static struct device_attribute *ahci_shost_attrs[] = {
 	&dev_attr_em_buffer,
 	NULL
 };
+EXPORT_SYMBOL_GPL(ahci_shost_attrs);

-static struct device_attribute *ahci_sdev_attrs[] = {
+struct device_attribute *ahci_sdev_attrs[] = {
 	&dev_attr_sw_activity,
 	&dev_attr_unload_heads,
 	NULL
 };
-
-struct scsi_host_template ahci_sht = {
-	ATA_NCQ_SHT("ahci"),
-	.can_queue		= AHCI_MAX_CMDS - 1,
-	.sg_tablesize		= AHCI_MAX_SG,
-	.dma_boundary		= AHCI_DMA_BOUNDARY,
-	.shost_attrs		= ahci_shost_attrs,
-	.sdev_attrs		= ahci_sdev_attrs,
-};
-EXPORT_SYMBOL_GPL(ahci_sht);
+EXPORT_SYMBOL_GPL(ahci_sdev_attrs);

 struct ata_port_operations ahci_ops = {
 	.inherits		= &sata_pmp_port_ops,