From: Simon Horman <horms@kernel•org>
To: Nick Child <nnac123@linux•ibm.com>
Cc: netdev@vger•kernel.org, haren@linux•ibm.com, ricklind@us•ibm.com,
danymadden@us•ibm.com, tlfalcon@linux•ibm.com,
bjking1@linux•ibm.com
Subject: Re: [PATCH net 4/5] ibmvnic: Do partial reset on login failure
Date: Sat, 5 Aug 2023 09:20:12 +0200 [thread overview]
Message-ID: <ZM34LJJMb2VLVllp@vergenet.net> (raw)
In-Reply-To: <20230803202010.37149-4-nnac123@linux.ibm.com>
On Thu, Aug 03, 2023 at 03:20:09PM -0500, Nick Child wrote:
> Perform a partial reset before sending a login request if any of the
> following are true:
> 1. If a previous request times out. This can be dangerous because the
> VIOS could still receive the old login request at any point after
> the timeout. Therefore, it is best to re-register the CRQ's and
> sub-CRQ's before retrying.
> 2. If the previous request returns an error that is not described in
> PAPR. PAPR provides procedures if the login returns with partial
> success or aborted return codes (section L.5.1) but other values
> do not have a defined procedure. Previously, these conditions
> just returned error from the login function rather than trying
> to resolve the issue.
> This can cause further issues since most callers of the login
> function are not prepared to handle an error when logging in. This
> improper cleanup can lead to the device being permanently DOWN'd.
> For example, if the VIOS believes that the device is already logged
> in then it will return INVALID_STATE (-7). If we never re-register
> CRQ's then it will always think that the device is already logged
> in. This leaves the device inoperable.
>
> The partial reset involves freeing the sub-CRQs, freeing the CRQ then
> registering and initializing a new CRQ and sub-CRQs. This essentially
> restarts all communication with VIOS to allow for a fresh login attempt
> that will be unhindered by any previous failed attempts.
>
> Fixes: dff515a3e71d ("ibmvnic: Harden device login requests")
> Signed-off-by: Nick Child <nnac123@linux•ibm.com>
Reviewed-by: Simon Horman <horms@kernel•org>
next prev parent reply other threads:[~2023-08-05 7:20 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-03 20:20 [PATCH net 1/5] ibmvnic: Enforce stronger sanity checks on login response Nick Child
2023-08-03 20:20 ` [PATCH net 2/5] ibmvnic: Unmap DMA login rsp buffer on send login fail Nick Child
2023-08-05 7:19 ` Simon Horman
2023-08-03 20:20 ` [PATCH net 3/5] ibmvnic: Handle DMA unmapping of login buffs in release functions Nick Child
2023-08-05 7:19 ` Simon Horman
2023-08-03 20:20 ` [PATCH net 4/5] ibmvnic: Do partial reset on login failure Nick Child
2023-08-05 7:20 ` Simon Horman [this message]
2023-08-03 20:20 ` [PATCH net 5/5] ibmvnic: Ensure login failure recovery is safe from other resets Nick Child
2023-08-05 7:20 ` Simon Horman
2023-08-08 2:13 ` Jakub Kicinski
2023-08-05 7:18 ` [PATCH net 1/5] ibmvnic: Enforce stronger sanity checks on login response Simon Horman
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