[patch net-next v2] devlink: remove reload failed checks in params get/set callbacks

[patch net-next v2] devlink: remove reload failed checks in params get/set callbacks

[Jiri Pirko]

From: Jiri Pirko <jiri@nvidia.com>

The checks in question were introduced by:
commit 6b4db2e528f6 ("devlink: Fix use-after-free after a failed reload").
That fixed an issue of reload with mlxsw driver.

Back then, that was a valid fix, because there was a limitation
in place that prevented drivers from registering/unregistering params
when devlink instance was registered.

It was possible to do the fix differently by changing drivers to
register/unregister params in appropriate places making sure the ops
operate only on memory which is allocated and initialized. But that,
as a dependency, would require to remove the limitation mentioned above.

Eventually, this limitation was lifted by:
commit 1d18bb1a4ddd ("devlink: allow registering parameters after the instance")

Also, the alternative fix (which also fixed another issue) was done by:
commit 74cbc3c03c82 ("mlxsw: spectrum_acl_tcam: Move devlink param to TCAM code").

Therefore, the checks are no longer relevant. Each driver should make
sure to have the params registered only when the memory the ops
are working with is allocated and initialized.

So remove the checks.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
v1->v2:
- rephrased some bits of the patch description
---
 net/devlink/leftover.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/devlink/leftover.c b/net/devlink/leftover.c
index 1f00f874471f..5128b9c7eea8 100644
--- a/net/devlink/leftover.c
+++ b/net/devlink/leftover.c
@@ -3946,7 +3946,7 @@ static int devlink_param_get(struct devlink *devlink,
 			     const struct devlink_param *param,
 			     struct devlink_param_gset_ctx *ctx)
 {
-	if (!param->get || devlink->reload_failed)
+	if (!param->get)
 		return -EOPNOTSUPP;
 	return param->get(devlink, param->id, ctx);
 }
@@ -3955,7 +3955,7 @@ static int devlink_param_set(struct devlink *devlink,
 			     const struct devlink_param *param,
 			     struct devlink_param_gset_ctx *ctx)
 {
-	if (!param->set || devlink->reload_failed)
+	if (!param->set)
 		return -EOPNOTSUPP;
 	return param->set(devlink, param->id, ctx);
 }
-- 
2.39.2

Re: [patch net-next v2] devlink: remove reload failed checks in params get/set callbacks

[Ido Schimmel]

On Thu, Jul 13, 2023 at 11:44:19AM +0200, Jiri Pirko wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> The checks in question were introduced by:
> commit 6b4db2e528f6 ("devlink: Fix use-after-free after a failed reload").
> That fixed an issue of reload with mlxsw driver.
> 
> Back then, that was a valid fix, because there was a limitation
> in place that prevented drivers from registering/unregistering params
> when devlink instance was registered.
> 
> It was possible to do the fix differently by changing drivers to
> register/unregister params in appropriate places making sure the ops
> operate only on memory which is allocated and initialized. But that,
> as a dependency, would require to remove the limitation mentioned above.
> 
> Eventually, this limitation was lifted by:
> commit 1d18bb1a4ddd ("devlink: allow registering parameters after the instance")
> 
> Also, the alternative fix (which also fixed another issue) was done by:
> commit 74cbc3c03c82 ("mlxsw: spectrum_acl_tcam: Move devlink param to TCAM code").
> 
> Therefore, the checks are no longer relevant. Each driver should make
> sure to have the params registered only when the memory the ops
> are working with is allocated and initialized.
> 
> So remove the checks.
> 
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

Re: [patch net-next v2] devlink: remove reload failed checks in params get/set callbacks

[Jakub Kicinski]

On Thu, 13 Jul 2023 11:44:19 +0200 Jiri Pirko wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> The checks in question were introduced by:
> commit 6b4db2e528f6 ("devlink: Fix use-after-free after a failed reload").
> That fixed an issue of reload with mlxsw driver.
> 
> Back then, that was a valid fix, because there was a limitation
> in place that prevented drivers from registering/unregistering params
> when devlink instance was registered.
> 
> It was possible to do the fix differently by changing drivers to
> register/unregister params in appropriate places making sure the ops
> operate only on memory which is allocated and initialized. But that,
> as a dependency, would require to remove the limitation mentioned above.
> 
> Eventually, this limitation was lifted by:
> commit 1d18bb1a4ddd ("devlink: allow registering parameters after the instance")
> 
> Also, the alternative fix (which also fixed another issue) was done by:
> commit 74cbc3c03c82 ("mlxsw: spectrum_acl_tcam: Move devlink param to TCAM code").
> 
> Therefore, the checks are no longer relevant. Each driver should make
> sure to have the params registered only when the memory the ops
> are working with is allocated and initialized.
> 
> So remove the checks.
> 
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>

Reviewed-by: Jakub Kicinski <kuba@kernel.org>

Re: [patch net-next v2] devlink: remove reload failed checks in params get/set callbacks

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by David S. Miller <davem@davemloft.net>:

On Thu, 13 Jul 2023 11:44:19 +0200 you wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> The checks in question were introduced by:
> commit 6b4db2e528f6 ("devlink: Fix use-after-free after a failed reload").
> That fixed an issue of reload with mlxsw driver.
> 
> Back then, that was a valid fix, because there was a limitation
> in place that prevented drivers from registering/unregistering params
> when devlink instance was registered.
> 
> [...]

Here is the summary with links:
  - [net-next,v2] devlink: remove reload failed checks in params get/set callbacks
    https://git.kernel.org/netdev/net-next/c/633d76ad01ad

You are awesome, thank you!
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