[PATCH 0/2] powerpc - EHEA fixes

[PATCH 0/2] powerpc - EHEA fixes

[Sebastien Dugue]

  Hi,

  here are 2 fixes for the ehea driver (nothing urgent here):

  - fix a typo which prevents building when DEBUG is #defined
  - fix mutex and spinlock usage in ehea_main

  and the diffstat for the patchset:

 drivers/net/ehea/ehea_main.c |   26 ++++----------------------
 drivers/net/ehea/ehea_phyp.c |    2 +-
 2 files changed, 5 insertions(+), 23 deletions(-)

  Thanks,

  Sebastien.

[PATCH 1/2] ehea: fix phyp debugging typo

[Sebastien Dugue]

  Fix typo in ehea_h_query_ehea() which prevents building when DEBUG is on.

Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
---
 drivers/net/ehea/ehea_phyp.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ehea/ehea_phyp.c b/drivers/net/ehea/ehea_phyp.c
index 156eb63..2a33a61 100644
--- a/drivers/net/ehea/ehea_phyp.c
+++ b/drivers/net/ehea/ehea_phyp.c
@@ -535,7 +535,7 @@ u64 ehea_h_query_ehea(const u64 adapter_handle, void *cb_addr)
 				       cb_logaddr,		/* R5 */
 				       0, 0, 0, 0, 0);		/* R6-R10 */
 #ifdef DEBUG
-	ehea_dmp(cb_addr, sizeof(struct hcp_query_ehea), "hcp_query_ehea");
+	ehea_dump(cb_addr, sizeof(struct hcp_query_ehea), "hcp_query_ehea");
 #endif
 	return hret;
 }
-- 
1.6.0.1.308.gede4c

[PATCH 2/2] ehea: fix mutex and spinlock use

[Sebastien Dugue]

  Looks like to me that the ehea_fw_handles.lock mutex and the
ehea_bcmc_regs.lock spinlock are taken much longer than necessary and could
as well be pushed inside the functions that need them
(ehea_update_firmware_handles() and ehea_update_bcmc_registrations())
rather than at each callsite.

Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
---
 drivers/net/ehea/ehea_main.c |   26 ++++----------------------
 1 files changed, 4 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
index b70c531..c765ec6 100644
--- a/drivers/net/ehea/ehea_main.c
+++ b/drivers/net/ehea/ehea_main.c
@@ -219,9 +219,11 @@ static void ehea_update_firmware_handles(void)
 	}
 
 out_update:
+	mutex_lock(&ehea_fw_handles.lock);
 	kfree(ehea_fw_handles.arr);
 	ehea_fw_handles.arr = arr;
 	ehea_fw_handles.num_entries = i;
+	mutex_unlock(&ehea_fw_handles.lock);
 }
 
 static void ehea_update_bcmc_registrations(void)
@@ -293,9 +295,11 @@ static void ehea_update_bcmc_registrations(void)
 	}
 
 out_update:
+	spin_lock(&ehea_bcmc_regs.lock);
 	kfree(ehea_bcmc_regs.arr);
 	ehea_bcmc_regs.arr = arr;
 	ehea_bcmc_regs.num_entries = i;
+	spin_unlock(&ehea_bcmc_regs.lock);
 }
 
 static struct net_device_stats *ehea_get_stats(struct net_device *dev)
@@ -1770,8 +1774,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
 
 	memcpy(dev->dev_addr, mac_addr->sa_data, dev->addr_len);
 
-	spin_lock(&ehea_bcmc_regs.lock);
-
 	/* Deregister old MAC in pHYP */
 	if (port->state == EHEA_PORT_UP) {
 		ret = ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
@@ -1792,7 +1794,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
 
 out_upregs:
 	ehea_update_bcmc_registrations();
-	spin_unlock(&ehea_bcmc_regs.lock);
 out_free:
 	kfree(cb0);
 out:
@@ -1954,8 +1955,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
 	}
 	ehea_promiscuous(dev, 0);
 
-	spin_lock(&ehea_bcmc_regs.lock);
-
 	if (dev->flags & IFF_ALLMULTI) {
 		ehea_allmulti(dev, 1);
 		goto out;
@@ -1985,7 +1984,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
 	}
 out:
 	ehea_update_bcmc_registrations();
-	spin_unlock(&ehea_bcmc_regs.lock);
 	return;
 }
 
@@ -2466,8 +2464,6 @@ static int ehea_up(struct net_device *dev)
 	if (port->state == EHEA_PORT_UP)
 		return 0;
 
-	mutex_lock(&ehea_fw_handles.lock);
-
 	ret = ehea_port_res_setup(port, port->num_def_qps,
 				  port->num_add_tx_qps);
 	if (ret) {
@@ -2504,8 +2500,6 @@ static int ehea_up(struct net_device *dev)
 		}
 	}
 
-	spin_lock(&ehea_bcmc_regs.lock);
-
 	ret = ehea_broadcast_reg_helper(port, H_REG_BCMC);
 	if (ret) {
 		ret = -EIO;
@@ -2527,10 +2521,8 @@ out:
 		ehea_info("Failed starting %s. ret=%i", dev->name, ret);
 
 	ehea_update_bcmc_registrations();
-	spin_unlock(&ehea_bcmc_regs.lock);
 
 	ehea_update_firmware_handles();
-	mutex_unlock(&ehea_fw_handles.lock);
 
 	return ret;
 }
@@ -2580,9 +2572,6 @@ static int ehea_down(struct net_device *dev)
 	if (port->state == EHEA_PORT_DOWN)
 		return 0;
 
-	mutex_lock(&ehea_fw_handles.lock);
-
-	spin_lock(&ehea_bcmc_regs.lock);
 	ehea_drop_multicast_list(dev);
 	ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
 
@@ -2591,7 +2580,6 @@ static int ehea_down(struct net_device *dev)
 	port->state = EHEA_PORT_DOWN;
 
 	ehea_update_bcmc_registrations();
-	spin_unlock(&ehea_bcmc_regs.lock);
 
 	ret = ehea_clean_all_portres(port);
 	if (ret)
@@ -2599,7 +2587,6 @@ static int ehea_down(struct net_device *dev)
 			  dev->name, ret);
 
 	ehea_update_firmware_handles();
-	mutex_unlock(&ehea_fw_handles.lock);
 
 	return ret;
 }
@@ -3378,7 +3365,6 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
 		ehea_error("Invalid ibmebus device probed");
 		return -EINVAL;
 	}
-	mutex_lock(&ehea_fw_handles.lock);
 
 	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
 	if (!adapter) {
@@ -3462,7 +3448,6 @@ out_free_ad:
 
 out:
 	ehea_update_firmware_handles();
-	mutex_unlock(&ehea_fw_handles.lock);
 	return ret;
 }
 
@@ -3481,8 +3466,6 @@ static int __devexit ehea_remove(struct of_device *dev)
 
 	flush_scheduled_work();
 
-	mutex_lock(&ehea_fw_handles.lock);
-
 	ibmebus_free_irq(adapter->neq->attr.ist1, adapter);
 	tasklet_kill(&adapter->neq_tasklet);
 
@@ -3492,7 +3475,6 @@ static int __devexit ehea_remove(struct of_device *dev)
 	kfree(adapter);
 
 	ehea_update_firmware_handles();
-	mutex_unlock(&ehea_fw_handles.lock);
 
 	return 0;
 }
-- 
1.6.0.1.308.gede4c

Re: [PATCH 1/2] ehea: fix phyp debugging typo

[Jeff Garzik]

Sebastien Dugue wrote:
>   Fix typo in ehea_h_query_ehea() which prevents building when DEBUG is on.
> 
> Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
> ---
>  drivers/net/ehea/ehea_phyp.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/ehea/ehea_phyp.c b/drivers/net/ehea/ehea_phyp.c
> index 156eb63..2a33a61 100644
> --- a/drivers/net/ehea/ehea_phyp.c
> +++ b/drivers/net/ehea/ehea_phyp.c
> @@ -535,7 +535,7 @@ u64 ehea_h_query_ehea(const u64 adapter_handle, void *cb_addr)
>  				       cb_logaddr,		/* R5 */
>  				       0, 0, 0, 0, 0);		/* R6-R10 */
>  #ifdef DEBUG
> -	ehea_dmp(cb_addr, sizeof(struct hcp_query_ehea), "hcp_query_ehea");
> +	ehea_dump(cb_addr, sizeof(struct hcp_query_ehea), "hcp_query_ehea");
>  #endif
>  	return hret;

applied

Re: [PATCH 2/2] ehea: fix mutex and spinlock use

[Jeff Garzik]

Sebastien Dugue wrote:
>   Looks like to me that the ehea_fw_handles.lock mutex and the
> ehea_bcmc_regs.lock spinlock are taken much longer than necessary and could
> as well be pushed inside the functions that need them
> (ehea_update_firmware_handles() and ehea_update_bcmc_registrations())
> rather than at each callsite.
> 
> Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
> ---
>  drivers/net/ehea/ehea_main.c |   26 ++++----------------------
>  1 files changed, 4 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
> index b70c531..c765ec6 100644
> --- a/drivers/net/ehea/ehea_main.c
> +++ b/drivers/net/ehea/ehea_main.c
> @@ -219,9 +219,11 @@ static void ehea_update_firmware_handles(void)
>  	}
>  
>  out_update:
> +	mutex_lock(&ehea_fw_handles.lock);
>  	kfree(ehea_fw_handles.arr);
>  	ehea_fw_handles.arr = arr;
>  	ehea_fw_handles.num_entries = i;
> +	mutex_unlock(&ehea_fw_handles.lock);
>  }
>  
>  static void ehea_update_bcmc_registrations(void)
> @@ -293,9 +295,11 @@ static void ehea_update_bcmc_registrations(void)
>  	}
>  
>  out_update:
> +	spin_lock(&ehea_bcmc_regs.lock);
>  	kfree(ehea_bcmc_regs.arr);
>  	ehea_bcmc_regs.arr = arr;
>  	ehea_bcmc_regs.num_entries = i;
> +	spin_unlock(&ehea_bcmc_regs.lock);
>  }
>  
>  static struct net_device_stats *ehea_get_stats(struct net_device *dev)
> @@ -1770,8 +1774,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
>  
>  	memcpy(dev->dev_addr, mac_addr->sa_data, dev->addr_len);
>  
> -	spin_lock(&ehea_bcmc_regs.lock);
> -
>  	/* Deregister old MAC in pHYP */
>  	if (port->state == EHEA_PORT_UP) {
>  		ret = ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
> @@ -1792,7 +1794,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
>  
>  out_upregs:
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  out_free:
>  	kfree(cb0);
>  out:
> @@ -1954,8 +1955,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
>  	}
>  	ehea_promiscuous(dev, 0);
>  
> -	spin_lock(&ehea_bcmc_regs.lock);
> -
>  	if (dev->flags & IFF_ALLMULTI) {
>  		ehea_allmulti(dev, 1);
>  		goto out;
> @@ -1985,7 +1984,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
>  	}
>  out:
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  	return;
>  }
>  
> @@ -2466,8 +2464,6 @@ static int ehea_up(struct net_device *dev)
>  	if (port->state == EHEA_PORT_UP)
>  		return 0;
>  
> -	mutex_lock(&ehea_fw_handles.lock);
> -
>  	ret = ehea_port_res_setup(port, port->num_def_qps,
>  				  port->num_add_tx_qps);
>  	if (ret) {
> @@ -2504,8 +2500,6 @@ static int ehea_up(struct net_device *dev)
>  		}
>  	}
>  
> -	spin_lock(&ehea_bcmc_regs.lock);
> -
>  	ret = ehea_broadcast_reg_helper(port, H_REG_BCMC);
>  	if (ret) {
>  		ret = -EIO;
> @@ -2527,10 +2521,8 @@ out:
>  		ehea_info("Failed starting %s. ret=%i", dev->name, ret);
>  
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  
>  	ehea_update_firmware_handles();
> -	mutex_unlock(&ehea_fw_handles.lock);
>  
>  	return ret;
>  }
> @@ -2580,9 +2572,6 @@ static int ehea_down(struct net_device *dev)
>  	if (port->state == EHEA_PORT_DOWN)
>  		return 0;
>  
> -	mutex_lock(&ehea_fw_handles.lock);
> -
> -	spin_lock(&ehea_bcmc_regs.lock);
>  	ehea_drop_multicast_list(dev);
>  	ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
>  
> @@ -2591,7 +2580,6 @@ static int ehea_down(struct net_device *dev)
>  	port->state = EHEA_PORT_DOWN;
>  
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  
>  	ret = ehea_clean_all_portres(port);
>  	if (ret)
> @@ -2599,7 +2587,6 @@ static int ehea_down(struct net_device *dev)
>  			  dev->name, ret);
>  
>  	ehea_update_firmware_handles();
> -	mutex_unlock(&ehea_fw_handles.lock);
>  
>  	return ret;
>  }
> @@ -3378,7 +3365,6 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
>  		ehea_error("Invalid ibmebus device probed");
>  		return -EINVAL;
>  	}
> -	mutex_lock(&ehea_fw_handles.lock);
>  
>  	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
>  	if (!adapter) {
> @@ -3462,7 +3448,6 @@ out_free_ad:
>  
>  out:
>  	ehea_update_firmware_handles();
> -	mutex_unlock(&ehea_fw_handles.lock);
>  	return ret;
>  }
>  
> @@ -3481,8 +3466,6 @@ static int __devexit ehea_remove(struct of_device *dev)
>  
>  	flush_scheduled_work();
>  
> -	mutex_lock(&ehea_fw_handles.lock);
> -
>  	ibmebus_free_irq(adapter->neq->attr.ist1, adapter);
>  	tasklet_kill(&adapter->neq_tasklet);

applied

Re: [PATCH 2/2] ehea: fix mutex and spinlock use

[Thomas Klein]

NACK!

I regret but this patch is wrong. It is not sufficient to only lock
the replacement of an old list with a new list. Building up those
lists is a 3-step process:

1. Count the number of entries a list will contain and allocate mem
2. Fill the list
3. Replace old list with updated list

It's obvious that the contents of the list may not change during this
procedure. That means that not only the list build-up procedure must
be locked. It must be assured that no function that modifies the list's
content can be called while another list update is in progress.

Jeff, please revert this patch.

Thanks
Thomas



Sebastien Dugue wrote:
>   Looks like to me that the ehea_fw_handles.lock mutex and the
> ehea_bcmc_regs.lock spinlock are taken much longer than necessary and could
> as well be pushed inside the functions that need them
> (ehea_update_firmware_handles() and ehea_update_bcmc_registrations())
> rather than at each callsite.
> 
> Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
> ---
>  drivers/net/ehea/ehea_main.c |   26 ++++----------------------
>  1 files changed, 4 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
> index b70c531..c765ec6 100644
> --- a/drivers/net/ehea/ehea_main.c
> +++ b/drivers/net/ehea/ehea_main.c
> @@ -219,9 +219,11 @@ static void ehea_update_firmware_handles(void)
>  	}
>  
>  out_update:
> +	mutex_lock(&ehea_fw_handles.lock);
>  	kfree(ehea_fw_handles.arr);
>  	ehea_fw_handles.arr = arr;
>  	ehea_fw_handles.num_entries = i;
> +	mutex_unlock(&ehea_fw_handles.lock);
>  }
>  
>  static void ehea_update_bcmc_registrations(void)
> @@ -293,9 +295,11 @@ static void ehea_update_bcmc_registrations(void)
>  	}
>  
>  out_update:
> +	spin_lock(&ehea_bcmc_regs.lock);
>  	kfree(ehea_bcmc_regs.arr);
>  	ehea_bcmc_regs.arr = arr;
>  	ehea_bcmc_regs.num_entries = i;
> +	spin_unlock(&ehea_bcmc_regs.lock);
>  }
>  
>  static struct net_device_stats *ehea_get_stats(struct net_device *dev)
> @@ -1770,8 +1774,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
>  
>  	memcpy(dev->dev_addr, mac_addr->sa_data, dev->addr_len);
>  
> -	spin_lock(&ehea_bcmc_regs.lock);
> -
>  	/* Deregister old MAC in pHYP */
>  	if (port->state == EHEA_PORT_UP) {
>  		ret = ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
> @@ -1792,7 +1794,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
>  
>  out_upregs:
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  out_free:
>  	kfree(cb0);
>  out:
> @@ -1954,8 +1955,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
>  	}
>  	ehea_promiscuous(dev, 0);
>  
> -	spin_lock(&ehea_bcmc_regs.lock);
> -
>  	if (dev->flags & IFF_ALLMULTI) {
>  		ehea_allmulti(dev, 1);
>  		goto out;
> @@ -1985,7 +1984,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
>  	}
>  out:
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  	return;
>  }
>  
> @@ -2466,8 +2464,6 @@ static int ehea_up(struct net_device *dev)
>  	if (port->state == EHEA_PORT_UP)
>  		return 0;
>  
> -	mutex_lock(&ehea_fw_handles.lock);
> -
>  	ret = ehea_port_res_setup(port, port->num_def_qps,
>  				  port->num_add_tx_qps);
>  	if (ret) {
> @@ -2504,8 +2500,6 @@ static int ehea_up(struct net_device *dev)
>  		}
>  	}
>  
> -	spin_lock(&ehea_bcmc_regs.lock);
> -
>  	ret = ehea_broadcast_reg_helper(port, H_REG_BCMC);
>  	if (ret) {
>  		ret = -EIO;
> @@ -2527,10 +2521,8 @@ out:
>  		ehea_info("Failed starting %s. ret=%i", dev->name, ret);
>  
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  
>  	ehea_update_firmware_handles();
> -	mutex_unlock(&ehea_fw_handles.lock);
>  
>  	return ret;
>  }
> @@ -2580,9 +2572,6 @@ static int ehea_down(struct net_device *dev)
>  	if (port->state == EHEA_PORT_DOWN)
>  		return 0;
>  
> -	mutex_lock(&ehea_fw_handles.lock);
> -
> -	spin_lock(&ehea_bcmc_regs.lock);
>  	ehea_drop_multicast_list(dev);
>  	ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
>  
> @@ -2591,7 +2580,6 @@ static int ehea_down(struct net_device *dev)
>  	port->state = EHEA_PORT_DOWN;
>  
>  	ehea_update_bcmc_registrations();
> -	spin_unlock(&ehea_bcmc_regs.lock);
>  
>  	ret = ehea_clean_all_portres(port);
>  	if (ret)
> @@ -2599,7 +2587,6 @@ static int ehea_down(struct net_device *dev)
>  			  dev->name, ret);
>  
>  	ehea_update_firmware_handles();
> -	mutex_unlock(&ehea_fw_handles.lock);
>  
>  	return ret;
>  }
> @@ -3378,7 +3365,6 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
>  		ehea_error("Invalid ibmebus device probed");
>  		return -EINVAL;
>  	}
> -	mutex_lock(&ehea_fw_handles.lock);
>  
>  	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
>  	if (!adapter) {
> @@ -3462,7 +3448,6 @@ out_free_ad:
>  
>  out:
>  	ehea_update_firmware_handles();
> -	mutex_unlock(&ehea_fw_handles.lock);
>  	return ret;
>  }
>  
> @@ -3481,8 +3466,6 @@ static int __devexit ehea_remove(struct of_device *dev)
>  
>  	flush_scheduled_work();
>  
> -	mutex_lock(&ehea_fw_handles.lock);
> -
>  	ibmebus_free_irq(adapter->neq->attr.ist1, adapter);
>  	tasklet_kill(&adapter->neq_tasklet);
>  
> @@ -3492,7 +3475,6 @@ static int __devexit ehea_remove(struct of_device *dev)
>  	kfree(adapter);
>  
>  	ehea_update_firmware_handles();
> -	mutex_unlock(&ehea_fw_handles.lock);
>  
>  	return 0;
>  }

Re: [PATCH 2/2] ehea: fix mutex and spinlock use

[Sebastien Dugue]

On Mon, 15 Sep 2008 17:18:27 +0200 Thomas Klein <osstklei@de.ibm.com> wrote:

> NACK!
> 
> I regret but this patch is wrong. It is not sufficient to only lock
> the replacement of an old list with a new list. Building up those
> lists is a 3-step process:
> 
> 1. Count the number of entries a list will contain and allocate mem
> 2. Fill the list
> 3. Replace old list with updated list
> 
> It's obvious that the contents of the list may not change during this
> procedure. That means that not only the list build-up procedure must
> be locked. It must be assured that no function that modifies the list's
> content can be called while another list update is in progress.
> 
> Jeff, please revert this patch.

  OK, your call, you know the code better than I do.

  But the locking could at least be pushed into ehea_update_firmware_handles()
and ehea_update_bcmc_registrations() instead of being at each call site.

  Thanks,

  Sebastien.

> 
> Thanks
> Thomas
> 
> 
> 
> Sebastien Dugue wrote:
> >   Looks like to me that the ehea_fw_handles.lock mutex and the
> > ehea_bcmc_regs.lock spinlock are taken much longer than necessary and could
> > as well be pushed inside the functions that need them
> > (ehea_update_firmware_handles() and ehea_update_bcmc_registrations())
> > rather than at each callsite.
> > 
> > Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
> > ---
> >  drivers/net/ehea/ehea_main.c |   26 ++++----------------------
> >  1 files changed, 4 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
> > index b70c531..c765ec6 100644
> > --- a/drivers/net/ehea/ehea_main.c
> > +++ b/drivers/net/ehea/ehea_main.c
> > @@ -219,9 +219,11 @@ static void ehea_update_firmware_handles(void)
> >  	}
> >  
> >  out_update:
> > +	mutex_lock(&ehea_fw_handles.lock);
> >  	kfree(ehea_fw_handles.arr);
> >  	ehea_fw_handles.arr = arr;
> >  	ehea_fw_handles.num_entries = i;
> > +	mutex_unlock(&ehea_fw_handles.lock);
> >  }
> >  
> >  static void ehea_update_bcmc_registrations(void)
> > @@ -293,9 +295,11 @@ static void ehea_update_bcmc_registrations(void)
> >  	}
> >  
> >  out_update:
> > +	spin_lock(&ehea_bcmc_regs.lock);
> >  	kfree(ehea_bcmc_regs.arr);
> >  	ehea_bcmc_regs.arr = arr;
> >  	ehea_bcmc_regs.num_entries = i;
> > +	spin_unlock(&ehea_bcmc_regs.lock);
> >  }
> >  
> >  static struct net_device_stats *ehea_get_stats(struct net_device *dev)
> > @@ -1770,8 +1774,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
> >  
> >  	memcpy(dev->dev_addr, mac_addr->sa_data, dev->addr_len);
> >  
> > -	spin_lock(&ehea_bcmc_regs.lock);
> > -
> >  	/* Deregister old MAC in pHYP */
> >  	if (port->state == EHEA_PORT_UP) {
> >  		ret = ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
> > @@ -1792,7 +1794,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
> >  
> >  out_upregs:
> >  	ehea_update_bcmc_registrations();
> > -	spin_unlock(&ehea_bcmc_regs.lock);
> >  out_free:
> >  	kfree(cb0);
> >  out:
> > @@ -1954,8 +1955,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
> >  	}
> >  	ehea_promiscuous(dev, 0);
> >  
> > -	spin_lock(&ehea_bcmc_regs.lock);
> > -
> >  	if (dev->flags & IFF_ALLMULTI) {
> >  		ehea_allmulti(dev, 1);
> >  		goto out;
> > @@ -1985,7 +1984,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
> >  	}
> >  out:
> >  	ehea_update_bcmc_registrations();
> > -	spin_unlock(&ehea_bcmc_regs.lock);
> >  	return;
> >  }
> >  
> > @@ -2466,8 +2464,6 @@ static int ehea_up(struct net_device *dev)
> >  	if (port->state == EHEA_PORT_UP)
> >  		return 0;
> >  
> > -	mutex_lock(&ehea_fw_handles.lock);
> > -
> >  	ret = ehea_port_res_setup(port, port->num_def_qps,
> >  				  port->num_add_tx_qps);
> >  	if (ret) {
> > @@ -2504,8 +2500,6 @@ static int ehea_up(struct net_device *dev)
> >  		}
> >  	}
> >  
> > -	spin_lock(&ehea_bcmc_regs.lock);
> > -
> >  	ret = ehea_broadcast_reg_helper(port, H_REG_BCMC);
> >  	if (ret) {
> >  		ret = -EIO;
> > @@ -2527,10 +2521,8 @@ out:
> >  		ehea_info("Failed starting %s. ret=%i", dev->name, ret);
> >  
> >  	ehea_update_bcmc_registrations();
> > -	spin_unlock(&ehea_bcmc_regs.lock);
> >  
> >  	ehea_update_firmware_handles();
> > -	mutex_unlock(&ehea_fw_handles.lock);
> >  
> >  	return ret;
> >  }
> > @@ -2580,9 +2572,6 @@ static int ehea_down(struct net_device *dev)
> >  	if (port->state == EHEA_PORT_DOWN)
> >  		return 0;
> >  
> > -	mutex_lock(&ehea_fw_handles.lock);
> > -
> > -	spin_lock(&ehea_bcmc_regs.lock);
> >  	ehea_drop_multicast_list(dev);
> >  	ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
> >  
> > @@ -2591,7 +2580,6 @@ static int ehea_down(struct net_device *dev)
> >  	port->state = EHEA_PORT_DOWN;
> >  
> >  	ehea_update_bcmc_registrations();
> > -	spin_unlock(&ehea_bcmc_regs.lock);
> >  
> >  	ret = ehea_clean_all_portres(port);
> >  	if (ret)
> > @@ -2599,7 +2587,6 @@ static int ehea_down(struct net_device *dev)
> >  			  dev->name, ret);
> >  
> >  	ehea_update_firmware_handles();
> > -	mutex_unlock(&ehea_fw_handles.lock);
> >  
> >  	return ret;
> >  }
> > @@ -3378,7 +3365,6 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
> >  		ehea_error("Invalid ibmebus device probed");
> >  		return -EINVAL;
> >  	}
> > -	mutex_lock(&ehea_fw_handles.lock);
> >  
> >  	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
> >  	if (!adapter) {
> > @@ -3462,7 +3448,6 @@ out_free_ad:
> >  
> >  out:
> >  	ehea_update_firmware_handles();
> > -	mutex_unlock(&ehea_fw_handles.lock);
> >  	return ret;
> >  }
> >  
> > @@ -3481,8 +3466,6 @@ static int __devexit ehea_remove(struct of_device *dev)
> >  
> >  	flush_scheduled_work();
> >  
> > -	mutex_lock(&ehea_fw_handles.lock);
> > -
> >  	ibmebus_free_irq(adapter->neq->attr.ist1, adapter);
> >  	tasklet_kill(&adapter->neq_tasklet);
> >  
> > @@ -3492,7 +3475,6 @@ static int __devexit ehea_remove(struct of_device *dev)
> >  	kfree(adapter);
> >  
> >  	ehea_update_firmware_handles();
> > -	mutex_unlock(&ehea_fw_handles.lock);
> >  
> >  	return 0;
> >  }
> 
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
> 

Re: [PATCH 2/2] ehea: fix mutex and spinlock use

[Thomas Klein]

Sebastien Dugue wrote:
> On Mon, 15 Sep 2008 17:18:27 +0200 Thomas Klein <osstklei@de.ibm.com> wrote:
> 
>> NACK!
>>
>> I regret but this patch is wrong. It is not sufficient to only lock
>> the replacement of an old list with a new list. Building up those
>> lists is a 3-step process:
>>
>> 1. Count the number of entries a list will contain and allocate mem
>> 2. Fill the list
>> 3. Replace old list with updated list
>>
>> It's obvious that the contents of the list may not change during this
>> procedure. That means that not only the list build-up procedure must
>> be locked. It must be assured that no function that modifies the list's
>> content can be called while another list update is in progress.
>>
>> Jeff, please revert this patch.
> 
>   OK, your call, you know the code better than I do.
> 
>   But the locking could at least be pushed into ehea_update_firmware_handles()
> and ehea_update_bcmc_registrations() instead of being at each call site.
> 
>   Thanks,
> 
>   Sebastien.
> 

It unfortunately can't. As I already mentioned "it must be assured that no
function that modifies the list's content can be called while another list
update is in progress". This means that for example ehea_broadcast_reg_helper()
may not run during a list update. That's why the locks surround these function
calls as well.

Thomas


>> Thanks
>> Thomas
>>
>>
>>
>> Sebastien Dugue wrote:
>>>   Looks like to me that the ehea_fw_handles.lock mutex and the
>>> ehea_bcmc_regs.lock spinlock are taken much longer than necessary and could
>>> as well be pushed inside the functions that need them
>>> (ehea_update_firmware_handles() and ehea_update_bcmc_registrations())
>>> rather than at each callsite.
>>>
>>> Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
>>> ---
>>>  drivers/net/ehea/ehea_main.c |   26 ++++----------------------
>>>  1 files changed, 4 insertions(+), 22 deletions(-)
>>>
>>> diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
>>> index b70c531..c765ec6 100644
>>> --- a/drivers/net/ehea/ehea_main.c
>>> +++ b/drivers/net/ehea/ehea_main.c
>>> @@ -219,9 +219,11 @@ static void ehea_update_firmware_handles(void)
>>>  	}
>>>  
>>>  out_update:
>>> +	mutex_lock(&ehea_fw_handles.lock);
>>>  	kfree(ehea_fw_handles.arr);
>>>  	ehea_fw_handles.arr = arr;
>>>  	ehea_fw_handles.num_entries = i;
>>> +	mutex_unlock(&ehea_fw_handles.lock);
>>>  }
>>>  
>>>  static void ehea_update_bcmc_registrations(void)
>>> @@ -293,9 +295,11 @@ static void ehea_update_bcmc_registrations(void)
>>>  	}
>>>  
>>>  out_update:
>>> +	spin_lock(&ehea_bcmc_regs.lock);
>>>  	kfree(ehea_bcmc_regs.arr);
>>>  	ehea_bcmc_regs.arr = arr;
>>>  	ehea_bcmc_regs.num_entries = i;
>>> +	spin_unlock(&ehea_bcmc_regs.lock);
>>>  }
>>>  
>>>  static struct net_device_stats *ehea_get_stats(struct net_device *dev)
>>> @@ -1770,8 +1774,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
>>>  
>>>  	memcpy(dev->dev_addr, mac_addr->sa_data, dev->addr_len);
>>>  
>>> -	spin_lock(&ehea_bcmc_regs.lock);
>>> -
>>>  	/* Deregister old MAC in pHYP */
>>>  	if (port->state == EHEA_PORT_UP) {
>>>  		ret = ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
>>> @@ -1792,7 +1794,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
>>>  
>>>  out_upregs:
>>>  	ehea_update_bcmc_registrations();
>>> -	spin_unlock(&ehea_bcmc_regs.lock);
>>>  out_free:
>>>  	kfree(cb0);
>>>  out:
>>> @@ -1954,8 +1955,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
>>>  	}
>>>  	ehea_promiscuous(dev, 0);
>>>  
>>> -	spin_lock(&ehea_bcmc_regs.lock);
>>> -
>>>  	if (dev->flags & IFF_ALLMULTI) {
>>>  		ehea_allmulti(dev, 1);
>>>  		goto out;
>>> @@ -1985,7 +1984,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
>>>  	}
>>>  out:
>>>  	ehea_update_bcmc_registrations();
>>> -	spin_unlock(&ehea_bcmc_regs.lock);
>>>  	return;
>>>  }
>>>  
>>> @@ -2466,8 +2464,6 @@ static int ehea_up(struct net_device *dev)
>>>  	if (port->state == EHEA_PORT_UP)
>>>  		return 0;
>>>  
>>> -	mutex_lock(&ehea_fw_handles.lock);
>>> -
>>>  	ret = ehea_port_res_setup(port, port->num_def_qps,
>>>  				  port->num_add_tx_qps);
>>>  	if (ret) {
>>> @@ -2504,8 +2500,6 @@ static int ehea_up(struct net_device *dev)
>>>  		}
>>>  	}
>>>  
>>> -	spin_lock(&ehea_bcmc_regs.lock);
>>> -
>>>  	ret = ehea_broadcast_reg_helper(port, H_REG_BCMC);
>>>  	if (ret) {
>>>  		ret = -EIO;
>>> @@ -2527,10 +2521,8 @@ out:
>>>  		ehea_info("Failed starting %s. ret=%i", dev->name, ret);
>>>  
>>>  	ehea_update_bcmc_registrations();
>>> -	spin_unlock(&ehea_bcmc_regs.lock);
>>>  
>>>  	ehea_update_firmware_handles();
>>> -	mutex_unlock(&ehea_fw_handles.lock);
>>>  
>>>  	return ret;
>>>  }
>>> @@ -2580,9 +2572,6 @@ static int ehea_down(struct net_device *dev)
>>>  	if (port->state == EHEA_PORT_DOWN)
>>>  		return 0;
>>>  
>>> -	mutex_lock(&ehea_fw_handles.lock);
>>> -
>>> -	spin_lock(&ehea_bcmc_regs.lock);
>>>  	ehea_drop_multicast_list(dev);
>>>  	ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
>>>  
>>> @@ -2591,7 +2580,6 @@ static int ehea_down(struct net_device *dev)
>>>  	port->state = EHEA_PORT_DOWN;
>>>  
>>>  	ehea_update_bcmc_registrations();
>>> -	spin_unlock(&ehea_bcmc_regs.lock);
>>>  
>>>  	ret = ehea_clean_all_portres(port);
>>>  	if (ret)
>>> @@ -2599,7 +2587,6 @@ static int ehea_down(struct net_device *dev)
>>>  			  dev->name, ret);
>>>  
>>>  	ehea_update_firmware_handles();
>>> -	mutex_unlock(&ehea_fw_handles.lock);
>>>  
>>>  	return ret;
>>>  }
>>> @@ -3378,7 +3365,6 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
>>>  		ehea_error("Invalid ibmebus device probed");
>>>  		return -EINVAL;
>>>  	}
>>> -	mutex_lock(&ehea_fw_handles.lock);
>>>  
>>>  	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
>>>  	if (!adapter) {
>>> @@ -3462,7 +3448,6 @@ out_free_ad:
>>>  
>>>  out:
>>>  	ehea_update_firmware_handles();
>>> -	mutex_unlock(&ehea_fw_handles.lock);
>>>  	return ret;
>>>  }
>>>  
>>> @@ -3481,8 +3466,6 @@ static int __devexit ehea_remove(struct of_device *dev)
>>>  
>>>  	flush_scheduled_work();
>>>  
>>> -	mutex_lock(&ehea_fw_handles.lock);
>>> -
>>>  	ibmebus_free_irq(adapter->neq->attr.ist1, adapter);
>>>  	tasklet_kill(&adapter->neq_tasklet);
>>>  
>>> @@ -3492,7 +3475,6 @@ static int __devexit ehea_remove(struct of_device *dev)
>>>  	kfree(adapter);
>>>  
>>>  	ehea_update_firmware_handles();
>>> -	mutex_unlock(&ehea_fw_handles.lock);
>>>  
>>>  	return 0;
>>>  }
>>
>> _______________________________________________
>> Linuxppc-dev mailing list
>> Linuxppc-dev@ozlabs.org
>> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>>

Re: [PATCH 2/2] ehea: fix mutex and spinlock use

[Sebastien Dugue]

On Tue, 16 Sep 2008 11:13:13 +0200 Thomas Klein <osstklei@de.ibm.com> wrote:

> Sebastien Dugue wrote:
> > On Mon, 15 Sep 2008 17:18:27 +0200 Thomas Klein <osstklei@de.ibm.com> wrote:
> > 
> >> NACK!
> >>
> >> I regret but this patch is wrong. It is not sufficient to only lock
> >> the replacement of an old list with a new list. Building up those
> >> lists is a 3-step process:
> >>
> >> 1. Count the number of entries a list will contain and allocate mem
> >> 2. Fill the list
> >> 3. Replace old list with updated list
> >>
> >> It's obvious that the contents of the list may not change during this
> >> procedure. That means that not only the list build-up procedure must
> >> be locked. It must be assured that no function that modifies the list's
> >> content can be called while another list update is in progress.
> >>
> >> Jeff, please revert this patch.
> > 
> >   OK, your call, you know the code better than I do.
> > 
> >   But the locking could at least be pushed into ehea_update_firmware_handles()
> > and ehea_update_bcmc_registrations() instead of being at each call site.
> > 
> >   Thanks,
> > 
> >   Sebastien.
> > 
> 
> It unfortunately can't. As I already mentioned "it must be assured that no
> function that modifies the list's content can be called while another list
> update is in progress". This means that for example ehea_broadcast_reg_helper()
> may not run during a list update. That's why the locks surround these function
> calls as well.

  OK, I see.

  Thanks,

  Sebastien.

> 
> Thomas
> 
> 
> >> Thanks
> >> Thomas
> >>
> >>
> >>
> >> Sebastien Dugue wrote:
> >>>   Looks like to me that the ehea_fw_handles.lock mutex and the
> >>> ehea_bcmc_regs.lock spinlock are taken much longer than necessary and could
> >>> as well be pushed inside the functions that need them
> >>> (ehea_update_firmware_handles() and ehea_update_bcmc_registrations())
> >>> rather than at each callsite.
> >>>
> >>> Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
> >>> ---
> >>>  drivers/net/ehea/ehea_main.c |   26 ++++----------------------
> >>>  1 files changed, 4 insertions(+), 22 deletions(-)
> >>>
> >>> diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
> >>> index b70c531..c765ec6 100644
> >>> --- a/drivers/net/ehea/ehea_main.c
> >>> +++ b/drivers/net/ehea/ehea_main.c
> >>> @@ -219,9 +219,11 @@ static void ehea_update_firmware_handles(void)
> >>>  	}
> >>>  
> >>>  out_update:
> >>> +	mutex_lock(&ehea_fw_handles.lock);
> >>>  	kfree(ehea_fw_handles.arr);
> >>>  	ehea_fw_handles.arr = arr;
> >>>  	ehea_fw_handles.num_entries = i;
> >>> +	mutex_unlock(&ehea_fw_handles.lock);
> >>>  }
> >>>  
> >>>  static void ehea_update_bcmc_registrations(void)
> >>> @@ -293,9 +295,11 @@ static void ehea_update_bcmc_registrations(void)
> >>>  	}
> >>>  
> >>>  out_update:
> >>> +	spin_lock(&ehea_bcmc_regs.lock);
> >>>  	kfree(ehea_bcmc_regs.arr);
> >>>  	ehea_bcmc_regs.arr = arr;
> >>>  	ehea_bcmc_regs.num_entries = i;
> >>> +	spin_unlock(&ehea_bcmc_regs.lock);
> >>>  }
> >>>  
> >>>  static struct net_device_stats *ehea_get_stats(struct net_device *dev)
> >>> @@ -1770,8 +1774,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
> >>>  
> >>>  	memcpy(dev->dev_addr, mac_addr->sa_data, dev->addr_len);
> >>>  
> >>> -	spin_lock(&ehea_bcmc_regs.lock);
> >>> -
> >>>  	/* Deregister old MAC in pHYP */
> >>>  	if (port->state == EHEA_PORT_UP) {
> >>>  		ret = ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
> >>> @@ -1792,7 +1794,6 @@ static int ehea_set_mac_addr(struct net_device *dev, void *sa)
> >>>  
> >>>  out_upregs:
> >>>  	ehea_update_bcmc_registrations();
> >>> -	spin_unlock(&ehea_bcmc_regs.lock);
> >>>  out_free:
> >>>  	kfree(cb0);
> >>>  out:
> >>> @@ -1954,8 +1955,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
> >>>  	}
> >>>  	ehea_promiscuous(dev, 0);
> >>>  
> >>> -	spin_lock(&ehea_bcmc_regs.lock);
> >>> -
> >>>  	if (dev->flags & IFF_ALLMULTI) {
> >>>  		ehea_allmulti(dev, 1);
> >>>  		goto out;
> >>> @@ -1985,7 +1984,6 @@ static void ehea_set_multicast_list(struct net_device *dev)
> >>>  	}
> >>>  out:
> >>>  	ehea_update_bcmc_registrations();
> >>> -	spin_unlock(&ehea_bcmc_regs.lock);
> >>>  	return;
> >>>  }
> >>>  
> >>> @@ -2466,8 +2464,6 @@ static int ehea_up(struct net_device *dev)
> >>>  	if (port->state == EHEA_PORT_UP)
> >>>  		return 0;
> >>>  
> >>> -	mutex_lock(&ehea_fw_handles.lock);
> >>> -
> >>>  	ret = ehea_port_res_setup(port, port->num_def_qps,
> >>>  				  port->num_add_tx_qps);
> >>>  	if (ret) {
> >>> @@ -2504,8 +2500,6 @@ static int ehea_up(struct net_device *dev)
> >>>  		}
> >>>  	}
> >>>  
> >>> -	spin_lock(&ehea_bcmc_regs.lock);
> >>> -
> >>>  	ret = ehea_broadcast_reg_helper(port, H_REG_BCMC);
> >>>  	if (ret) {
> >>>  		ret = -EIO;
> >>> @@ -2527,10 +2521,8 @@ out:
> >>>  		ehea_info("Failed starting %s. ret=%i", dev->name, ret);
> >>>  
> >>>  	ehea_update_bcmc_registrations();
> >>> -	spin_unlock(&ehea_bcmc_regs.lock);
> >>>  
> >>>  	ehea_update_firmware_handles();
> >>> -	mutex_unlock(&ehea_fw_handles.lock);
> >>>  
> >>>  	return ret;
> >>>  }
> >>> @@ -2580,9 +2572,6 @@ static int ehea_down(struct net_device *dev)
> >>>  	if (port->state == EHEA_PORT_DOWN)
> >>>  		return 0;
> >>>  
> >>> -	mutex_lock(&ehea_fw_handles.lock);
> >>> -
> >>> -	spin_lock(&ehea_bcmc_regs.lock);
> >>>  	ehea_drop_multicast_list(dev);
> >>>  	ehea_broadcast_reg_helper(port, H_DEREG_BCMC);
> >>>  
> >>> @@ -2591,7 +2580,6 @@ static int ehea_down(struct net_device *dev)
> >>>  	port->state = EHEA_PORT_DOWN;
> >>>  
> >>>  	ehea_update_bcmc_registrations();
> >>> -	spin_unlock(&ehea_bcmc_regs.lock);
> >>>  
> >>>  	ret = ehea_clean_all_portres(port);
> >>>  	if (ret)
> >>> @@ -2599,7 +2587,6 @@ static int ehea_down(struct net_device *dev)
> >>>  			  dev->name, ret);
> >>>  
> >>>  	ehea_update_firmware_handles();
> >>> -	mutex_unlock(&ehea_fw_handles.lock);
> >>>  
> >>>  	return ret;
> >>>  }
> >>> @@ -3378,7 +3365,6 @@ static int __devinit ehea_probe_adapter(struct of_device *dev,
> >>>  		ehea_error("Invalid ibmebus device probed");
> >>>  		return -EINVAL;
> >>>  	}
> >>> -	mutex_lock(&ehea_fw_handles.lock);
> >>>  
> >>>  	adapter = kzalloc(sizeof(*adapter), GFP_KERNEL);
> >>>  	if (!adapter) {
> >>> @@ -3462,7 +3448,6 @@ out_free_ad:
> >>>  
> >>>  out:
> >>>  	ehea_update_firmware_handles();
> >>> -	mutex_unlock(&ehea_fw_handles.lock);
> >>>  	return ret;
> >>>  }
> >>>  
> >>> @@ -3481,8 +3466,6 @@ static int __devexit ehea_remove(struct of_device *dev)
> >>>  
> >>>  	flush_scheduled_work();
> >>>  
> >>> -	mutex_lock(&ehea_fw_handles.lock);
> >>> -
> >>>  	ibmebus_free_irq(adapter->neq->attr.ist1, adapter);
> >>>  	tasklet_kill(&adapter->neq_tasklet);
> >>>  
> >>> @@ -3492,7 +3475,6 @@ static int __devexit ehea_remove(struct of_device *dev)
> >>>  	kfree(adapter);
> >>>  
> >>>  	ehea_update_firmware_handles();
> >>> -	mutex_unlock(&ehea_fw_handles.lock);
> >>>  
> >>>  	return 0;
> >>>  }
> >>
> >> _______________________________________________
> >> Linuxppc-dev mailing list
> >> Linuxppc-dev@ozlabs.org
> >> https://ozlabs.org/mailman/listinfo/linuxppc-dev
> >>
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
> 

[PATCH 2/2] ehea: fix possible DLPAR/mem deadlock

[Thomas Klein]

Force serialization of userspace-triggered DLPAR/mem operations

Signed-off-by: Thomas Klein <tklein@de.ibm.com>
---

Patch created against 2.6.34-rc4

diff -Nurp linux-2.6.34-rc4.orig//drivers/net/ehea/ehea.h linux-2.6.34-rc4//drivers/net/ehea/ehea.h
--- linux-2.6.34-rc4.orig//drivers/net/ehea/ehea.h	2010-04-19 11:54:07.000000000 +0200
+++ linux-2.6.34-rc4//drivers/net/ehea/ehea.h	2010-04-19 12:00:14.000000000 +0200
@@ -40,7 +40,7 @@
  #include <asm/io.h>

  #define DRV_NAME	"ehea"
-#define DRV_VERSION	"EHEA_0102"
+#define DRV_VERSION	"EHEA_0103"

  /* eHEA capability flags */
  #define DLPAR_PORT_ADD_REM 1
diff -Nurp linux-2.6.34-rc4.orig//drivers/net/ehea/ehea_main.c linux-2.6.34-rc4//drivers/net/ehea/ehea_main.c
--- linux-2.6.34-rc4.orig//drivers/net/ehea/ehea_main.c	2010-04-19 11:59:11.000000000 +0200
+++ linux-2.6.34-rc4//drivers/net/ehea/ehea_main.c	2010-04-19 11:59:50.000000000 +0200
@@ -2889,7 +2889,6 @@ static void ehea_rereg_mrs(struct work_s
  	int ret, i;
  	struct ehea_adapter *adapter;

-	mutex_lock(&dlpar_mem_lock);
  	ehea_info("LPAR memory changed - re-initializing driver");

  	list_for_each_entry(adapter, &adapter_list, list)
@@ -2959,7 +2958,6 @@ static void ehea_rereg_mrs(struct work_s
  		}
  	ehea_info("re-initializing driver complete");
  out:
-	mutex_unlock(&dlpar_mem_lock);
  	return;
  }

@@ -3542,7 +3540,14 @@ void ehea_crash_handler(void)
  static int ehea_mem_notifier(struct notifier_block *nb,
                               unsigned long action, void *data)
  {
+	int ret = NOTIFY_BAD;
  	struct memory_notify *arg = data;
+
+	if (!mutex_trylock(&dlpar_mem_lock)) {
+		ehea_info("ehea_mem_notifier must not be called parallelized");
+		goto out;
+	}
+
  	switch (action) {
  	case MEM_CANCEL_OFFLINE:
  		ehea_info("memory offlining canceled");
@@ -3551,14 +3556,14 @@ static int ehea_mem_notifier(struct noti
  		ehea_info("memory is going online");
  		set_bit(__EHEA_STOP_XFER, &ehea_driver_flags);
  		if (ehea_add_sect_bmap(arg->start_pfn, arg->nr_pages))
-			return NOTIFY_BAD;
+			goto out_unlock;
  		ehea_rereg_mrs(NULL);
  		break;
  	case MEM_GOING_OFFLINE:
  		ehea_info("memory is going offline");
  		set_bit(__EHEA_STOP_XFER, &ehea_driver_flags);
  		if (ehea_rem_sect_bmap(arg->start_pfn, arg->nr_pages))
-			return NOTIFY_BAD;
+			goto out_unlock;
  		ehea_rereg_mrs(NULL);
  		break;
  	default:
@@ -3566,8 +3571,12 @@ static int ehea_mem_notifier(struct noti
  	}

  	ehea_update_firmware_handles();
+	ret = NOTIFY_OK;

-	return NOTIFY_OK;
+out_unlock:
+	mutex_unlock(&dlpar_mem_lock);
+out:
+	return ret;
  }

  static struct notifier_block ehea_mem_nb = {