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 72375DDDE0 for ; Tue, 16 Sep 2008 20:38:39 +1000 (EST) Date: Tue, 16 Sep 2008 12:38:13 +0200 From: Sebastien Dugue To: Thomas Klein Subject: Re: [PATCH 2/2] ehea: fix mutex and spinlock use Message-ID: <20080916123813.51ffd682@bull.net> In-Reply-To: <48CF78A9.9080907@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> <20080916085746.194c1510@bull.net> <48CF78A9.9080907@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, themann@de.ibm.com, netdev@vger.kernel.org, hering2@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 Tue, 16 Sep 2008 11:13:13 +0200 Thomas Klein wrote: > Sebastien Dugue wrote: > > 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. > > > > 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 > >>> --- > >>> 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 >