| Message ID | 20201231034524.1570729-1-kuba@kernel.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [net] docs: net: fix documentation on .ndo_get_stats | expand |
On Wed, Dec 30, 2020 at 07:45:24PM -0800, Jakub Kicinski wrote: > Fix calling context. > > Signed-off-by: Jakub Kicinski <kuba@kernel.org> > --- > Documentation/networking/netdevices.rst | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst > index 5a85fcc80c76..a80676f5477d 100644 > --- a/Documentation/networking/netdevices.rst > +++ b/Documentation/networking/netdevices.rst > @@ -64,8 +64,8 @@ struct net_device synchronization rules > Context: process > > ndo_get_stats: > - Synchronization: dev_base_lock rwlock. > - Context: nominally process, but don't sleep inside an rwlock > + Synchronization: rtnl_lock() semaphore, or RCU. > + Context: atomic > > ndo_start_xmit: > Synchronization: __netif_tx_lock spinlock. > -- > 2.26.2 > And what happened to dev_base_lock? Did it suddenly go away?
On Mon, 4 Jan 2021 12:42:27 +0200 Vladimir Oltean wrote: > On Wed, Dec 30, 2020 at 07:45:24PM -0800, Jakub Kicinski wrote: > > Fix calling context. > > > > Signed-off-by: Jakub Kicinski <kuba@kernel.org> > > --- > > Documentation/networking/netdevices.rst | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst > > index 5a85fcc80c76..a80676f5477d 100644 > > --- a/Documentation/networking/netdevices.rst > > +++ b/Documentation/networking/netdevices.rst > > @@ -64,8 +64,8 @@ struct net_device synchronization rules > > Context: process > > > > ndo_get_stats: > > - Synchronization: dev_base_lock rwlock. > > - Context: nominally process, but don't sleep inside an rwlock > > + Synchronization: rtnl_lock() semaphore, or RCU. > > + Context: atomic > > > > ndo_start_xmit: > > Synchronization: __netif_tx_lock spinlock. > > And what happened to dev_base_lock? Did it suddenly go away? I thought all callers switched to RCU. You investigated this in depth, did I miss something? I'm sending this correction because I have a series which adds to other sections of this file and this jumped out to me as incorrect.
On Mon, Jan 04, 2021 at 09:53:09AM -0800, Jakub Kicinski wrote: > On Mon, 4 Jan 2021 12:42:27 +0200 Vladimir Oltean wrote: > > On Wed, Dec 30, 2020 at 07:45:24PM -0800, Jakub Kicinski wrote: > > > Fix calling context. > > > > > > Signed-off-by: Jakub Kicinski <kuba@kernel.org> > > > --- > > > Documentation/networking/netdevices.rst | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst > > > index 5a85fcc80c76..a80676f5477d 100644 > > > --- a/Documentation/networking/netdevices.rst > > > +++ b/Documentation/networking/netdevices.rst > > > @@ -64,8 +64,8 @@ struct net_device synchronization rules > > > Context: process > > > > > > ndo_get_stats: > > > - Synchronization: dev_base_lock rwlock. > > > - Context: nominally process, but don't sleep inside an rwlock > > > + Synchronization: rtnl_lock() semaphore, or RCU. > > > + Context: atomic > > > > > > ndo_start_xmit: > > > Synchronization: __netif_tx_lock spinlock. > > > > And what happened to dev_base_lock? Did it suddenly go away? > > I thought all callers switched to RCU. You investigated this in depth, > did I miss something? I'm sending this correction because I have a > series which adds to other sections of this file and this jumped out > to me as incorrect. Well, there's netstat_show from net/core/net-sysfs.c still. I couldn't figure why that lock exists, it doesn't seem to protect something in particular.
On Tue, 5 Jan 2021 03:03:27 +0200 Vladimir Oltean wrote: > On Mon, Jan 04, 2021 at 09:53:09AM -0800, Jakub Kicinski wrote: > > On Mon, 4 Jan 2021 12:42:27 +0200 Vladimir Oltean wrote: > > > And what happened to dev_base_lock? Did it suddenly go away? > > > > I thought all callers switched to RCU. You investigated this in depth, > > did I miss something? I'm sending this correction because I have a > > series which adds to other sections of this file and this jumped out > > to me as incorrect. > > Well, there's netstat_show from net/core/net-sysfs.c still. I couldn't > figure why that lock exists, it doesn't seem to protect something in > particular. Ah, thanks for pointing that out, in that case I should just add RCU to the list of locks that may be held.
diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst index 5a85fcc80c76..a80676f5477d 100644 --- a/Documentation/networking/netdevices.rst +++ b/Documentation/networking/netdevices.rst @@ -64,8 +64,8 @@ struct net_device synchronization rules Context: process ndo_get_stats: - Synchronization: dev_base_lock rwlock. - Context: nominally process, but don't sleep inside an rwlock + Synchronization: rtnl_lock() semaphore, or RCU. + Context: atomic ndo_start_xmit: Synchronization: __netif_tx_lock spinlock.
Fix calling context. Signed-off-by: Jakub Kicinski <kuba@kernel.org> --- Documentation/networking/netdevices.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)