lkml.org 
[lkml]   [2008]   [Sep]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [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
    >>



    \
     
     \ /
      Last update: 2008-09-16 11:17    [W:0.040 / U:29.936 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site