From: David Laight <david.laight.linux@gmail.com>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jakub Kicinski <kuba@kernel.org>,
davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org,
jdamato@fastly.com, Francois Romieu <romieu@fr.zoreil.com>,
pcnet32@frontier.com, anthony.l.nguyen@intel.com,
przemyslaw.kitszel@intel.com, marcin.s.wojtas@gmail.com
Subject: Re: [PATCH net-next v2 06/11] net: protect NAPI enablement with netdev_lock()
Date: Tue, 21 Jan 2025 08:50:45 +0000 [thread overview]
Message-ID: <20250121085045.480c2e51@pumpkin> (raw)
In-Reply-To: <dcfd56bc-de32-4b11-9e19-d8bd1543745d@stanley.mountain>
On Tue, 21 Jan 2025 11:32:24 +0300
Dan Carpenter <dan.carpenter@linaro.org> wrote:
> On Tue, Jan 14, 2025 at 07:53:14PM -0800, Jakub Kicinski wrote:
> > Wrap napi_enable() / napi_disable() with netdev_lock().
> > Provide the "already locked" flavor of the API.
> >
> > iavf needs the usual adjustment. A number of drivers call
> > napi_enable() under a spin lock, so they have to be modified
> > to take netdev_lock() first, then spin lock then call
> > napi_enable_locked().
>
> You missed some.
>
> drivers/net/ethernet/broadcom/tg3.c:7427 tg3_napi_enable() warn: sleeping in atomic context
> drivers/net/ethernet/nvidia/forcedeth.c:5597 nv_open() warn: sleeping in atomic context
...
Looks like the whole patch is very fragile.
You really need to keep the existing function names having their existing semantics.
Add a new function, change all the code, then delete the old function.
It also looks as though drivers will end up holding netdev_lock() for long
periods just so they can do a napi_enable() much later on.
David
next prev parent reply other threads:[~2025-01-21 8:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-15 3:53 [PATCH net-next v2 00/11] net: use netdev->lock to protect NAPI Jakub Kicinski
2025-01-15 3:53 ` [PATCH net-next v2 01/11] net: add netdev_lock() / netdev_unlock() helpers Jakub Kicinski
2025-01-15 8:21 ` Kuniyuki Iwashima
2025-01-15 8:36 ` Przemek Kitszel
2025-01-15 9:24 ` Ido Schimmel
2025-01-15 14:08 ` Jakub Kicinski
2025-01-15 14:24 ` Przemek Kitszel
2025-01-15 3:53 ` [PATCH net-next v2 02/11] net: make netdev_lock() protect netdev->reg_state Jakub Kicinski
2025-01-15 8:30 ` Kuniyuki Iwashima
2025-01-15 14:18 ` Jakub Kicinski
2025-01-15 3:53 ` [PATCH net-next v2 03/11] net: add helpers for lookup and walking netdevs under netdev_lock() Jakub Kicinski
2025-01-15 8:41 ` Kuniyuki Iwashima
2025-01-15 3:53 ` [PATCH net-next v2 04/11] net: add netdev->up protected by netdev_lock() Jakub Kicinski
2025-01-15 8:45 ` Kuniyuki Iwashima
2025-01-15 3:53 ` [PATCH net-next v2 05/11] net: protect netdev->napi_list with netdev_lock() Jakub Kicinski
2025-01-15 8:57 ` Kuniyuki Iwashima
2025-01-17 22:21 ` Eric Dumazet
2025-01-17 22:52 ` Jakub Kicinski
2025-01-15 3:53 ` [PATCH net-next v2 06/11] net: protect NAPI enablement " Jakub Kicinski
2025-01-15 9:02 ` Kuniyuki Iwashima
2025-01-21 8:32 ` Dan Carpenter
2025-01-21 8:50 ` David Laight [this message]
2025-01-21 15:27 ` Dan Carpenter
2025-01-15 3:53 ` [PATCH net-next v2 07/11] net: make netdev netlink ops hold netdev_lock() Jakub Kicinski
2025-01-15 9:07 ` Kuniyuki Iwashima
2025-01-15 3:53 ` [PATCH net-next v2 08/11] net: protect threaded status of NAPI with netdev_lock() Jakub Kicinski
2025-01-15 9:09 ` Kuniyuki Iwashima
2025-01-15 3:53 ` [PATCH net-next v2 09/11] net: protect napi->irq " Jakub Kicinski
2025-01-15 9:12 ` Kuniyuki Iwashima
2025-01-15 3:53 ` [PATCH net-next v2 10/11] net: protect NAPI config fields " Jakub Kicinski
2025-01-15 9:15 ` Kuniyuki Iwashima
2025-01-15 3:53 ` [PATCH net-next v2 11/11] netdev-genl: remove rtnl_lock protection from NAPI ops Jakub Kicinski
2025-01-15 9:18 ` Kuniyuki Iwashima
2025-01-16 3:30 ` [PATCH net-next v2 00/11] net: use netdev->lock to protect NAPI patchwork-bot+netdevbpf
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