From: Jiri Pirko <jiri@resnulli•us>
To: "Keller, Jacob E" <jacob.e.keller@intel•com>
Cc: "netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"davem@davemloft•net" <davem@davemloft•net>,
"kuba@kernel•org" <kuba@kernel•org>,
"idosch@nvidia•com" <idosch@nvidia•com>,
"petrm@nvidia•com" <petrm@nvidia•com>,
"pabeni@redhat•com" <pabeni@redhat•com>,
"edumazet@google•com" <edumazet@google•com>,
"mlxsw@nvidia•com" <mlxsw@nvidia•com>,
"saeedm@nvidia•com" <saeedm@nvidia•com>,
"snelson@pensando•io" <snelson@pensando•io>
Subject: Re: [patch net-next v3 01/11] net: devlink: make sure that devlink_try_get() works with valid pointer during xarray iteration
Date: Fri, 22 Jul 2022 08:15:55 +0200 [thread overview]
Message-ID: <YtpAm245yK9pfQ+d@nanopsycho> (raw)
In-Reply-To: <SA2PR11MB5100CD9D0CBCDB2D0F76271CD6919@SA2PR11MB5100.namprd11.prod.outlook.com>
Thu, Jul 21, 2022 at 08:55:04PM CEST, jacob.e.keller@intel•com wrote:
>
>
>> -----Original Message-----
>> From: Jiri Pirko <jiri@resnulli•us>
>> Sent: Wednesday, July 20, 2022 10:45 PM
>> To: Keller, Jacob E <jacob.e.keller@intel•com>
>> Cc: netdev@vger•kernel.org; davem@davemloft•net; kuba@kernel•org;
>> idosch@nvidia•com; petrm@nvidia•com; pabeni@redhat•com;
>> edumazet@google•com; mlxsw@nvidia•com; saeedm@nvidia•com;
>> snelson@pensando•io
>> Subject: Re: [patch net-next v3 01/11] net: devlink: make sure that
>> devlink_try_get() works with valid pointer during xarray iteration
>>
>> >Is it safe to rcu_read_unlock here while we're still in the middle of the array
>> processing? What happens if something else updates the xarray? is the
>> for_each_marked safe?
>>
>> Sure, you don't need to hold rcu_read_lock during call to xa_for_each_marked.
>> The consistency of xarray is itself guaranteed. The only reason to take
>> rcu_read_lock outside is that the devlink pointer which is
>> rcu_dereference_check()'ed inside xa_for_each_marked() is still valid
>> once we devlink_try_get() it.
>>
>
>Excellent, ok. Basically we need the RCU for protecting just the pointer until we get a reference to it separately.
Yep.
>
>Thanks!
>
>In that case:
>
>Reviewed-by: Jacob Keller <jacob.e.keller@intel•com>
Thanks. I will send v4 soon wrapping this up into helper as Jakub
requested.
next prev parent reply other threads:[~2022-07-22 6:16 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-20 15:12 [patch net-next v3 00/11] mlxsw: Implement dev info and dev flash for line cards Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 01/11] net: devlink: make sure that devlink_try_get() works with valid pointer during xarray iteration Jiri Pirko
2022-07-20 22:25 ` Keller, Jacob E
2022-07-21 5:45 ` Jiri Pirko
2022-07-21 18:55 ` Keller, Jacob E
2022-07-22 6:15 ` Jiri Pirko [this message]
2022-07-21 0:49 ` Jakub Kicinski
2022-07-21 5:51 ` Jiri Pirko
2022-07-21 6:22 ` Jakub Kicinski
2022-07-21 12:04 ` Jiri Pirko
2022-07-22 6:15 ` Jiri Pirko
2022-07-22 15:50 ` Jiri Pirko
2022-07-22 18:23 ` Jakub Kicinski
2022-07-23 15:41 ` Jiri Pirko
2022-07-25 8:17 ` Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 02/11] net: devlink: introduce nested devlink entity for line card Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 03/11] mlxsw: core_linecards: Introduce per line card auxiliary device Jiri Pirko
2022-07-21 8:04 ` Ido Schimmel
2022-07-20 15:12 ` [patch net-next v3 04/11] mlxsw: core_linecards: Expose HW revision and INI version Jiri Pirko
2022-07-21 8:05 ` Ido Schimmel
2022-07-20 15:12 ` [patch net-next v3 05/11] mlxsw: reg: Extend MDDQ by device_info Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 06/11] mlxsw: core_linecards: Probe provisioned line cards for devices and expose FW version Jiri Pirko
2022-07-21 8:11 ` Ido Schimmel
2022-07-21 16:01 ` Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 07/11] mlxsw: reg: Add Management DownStream Device Tunneling Register Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 08/11] mlxsw: core_linecards: Expose device PSID over device info Jiri Pirko
2022-07-21 8:13 ` Ido Schimmel
2022-07-20 15:12 ` [patch net-next v3 09/11] mlxsw: core_linecards: Implement line card device flashing Jiri Pirko
2022-07-21 8:25 ` Ido Schimmel
2022-07-21 16:01 ` Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 10/11] selftests: mlxsw: Check line card info on provisioned line card Jiri Pirko
2022-07-20 15:12 ` [patch net-next v3 11/11] selftests: mlxsw: Check line card info on activated " Jiri Pirko
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