Messages in this thread | | | Date | Tue, 16 Sep 2008 11:13:13 +0200 | From | Thomas Klein <> | Subject | Re: [PATCH 2/2] ehea: fix mutex and spinlock use |
| |
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 >>
| |