Messages in this thread Patch in this message | | | Date | Mon, 15 Apr 2019 14:06:01 +0200 (CEST) | From | Jiri Kosina <> | Subject | Re: [PATCH v5.1-rc] iwlwifi: make locking in iwl_mvm_tx_mpdu() BH-safe |
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On Mon, 15 Apr 2019, Johannes Berg wrote:
> > If there are other reasons why disable BH for the whole function (are > > there?), then this bigger hammer works as well of course. > > I thought there are, but seeing the commit log here I'm not sure. > > In any case, even if not, the function itself is part of the TX fast > path, but the caller from the workqueue is very uncommon (basically only > happens for a handful of packets on each new RA/TID), so I'd say that'd > be a good reason to use the slightly bigger hammer (it's not that much > different really, if you look at how much code is covered by the lock) > and avoid doing it all the time when we know it to be not needed.
Given that we don't have a primitive in lockdep to assert this invariant, would you consider queuing the below on top of f5ae2f932e2f in wireless-drivers.git?
Thanks.
From: Jiri Kosina <jkosina@suse.cz> Subject: [PATCH] iwlwifi: iwl_mvm_tx_mpdu() must be called with BH disabled
As iwl_mvm_tx_mpdu() is not disabling BH while obtaining iwl_mvm_sta->lock (which is being taken from BH context as well), it has to be always invoked with BH disabled. Make that clear in a comment.
Signed-off-by: Jiri Kosina <jkosina@suse.cz> --- drivers/net/wireless/intel/iwlwifi/mvm/tx.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c index 0c2aabc842f9..ad4760307726 100644 --- a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c +++ b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c @@ -1063,7 +1063,9 @@ static int iwl_mvm_tx_pkt_queued(struct iwl_mvm *mvm, } /* - * Sets the fields in the Tx cmd that are crypto related + * Sets the fields in the Tx cmd that are crypto related. + * + * This function must be called with BHs disabled. */ static int iwl_mvm_tx_mpdu(struct iwl_mvm *mvm, struct sk_buff *skb, struct ieee80211_tx_info *info, -- Jiri Kosina SUSE Labs
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