From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ecfrec.frec.bull.fr (ecfrec.frec.bull.fr [129.183.4.8]) by ozlabs.org (Postfix) with ESMTP id 74052DDEE1 for ; Tue, 16 Sep 2008 16:57:57 +1000 (EST) Date: Tue, 16 Sep 2008 08:57:46 +0200 From: Sebastien Dugue To: Thomas Klein Subject: Re: [PATCH 2/2] ehea: fix mutex and spinlock use Message-ID: <20080916085746.194c1510@bull.net> In-Reply-To: <48CE7CC3.8040902@de.ibm.com> References: <1221140080-9853-1-git-send-email-sebastien.dugue@bull.net> <1221140080-9853-3-git-send-email-sebastien.dugue@bull.net> <48CE7CC3.8040902@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: tklein@de.ibm.com, tinytim@us.ibm.com, jeff@garzik.org, hering2@de.ibm.com, netdev@vger.kernel.org, themann@de.ibm.com, linux-kernel@vger.kernel.org, jean-pierre.dion@bull.net, linuxppc-dev@ozlabs.org, raisch@de.ibm.com, gilles.carry@ext.bull.net List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 15 Sep 2008 17:18:27 +0200 Thomas Klein 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 > > --- > > 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 >