> > > > While inspecting the code, I saw that iwl_tx_queue_unmap modifies > > > > the read pointer of the Tx queue without taking any locks. This means > > > > that it can race with the reclaim flow. This can possibly lead to > > > > a DMA warning complaining that we unmap the same buffer twice. > > > > > > > > This is more a W/A than a fix since it is really weird to take > > > > sta_lock inside iwl_tx_queue_unmap, but it can help until we revamp > > > > the locking model in the transport layer. > > > > > > > > Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx> > > > > Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@xxxxxxxxx> > > > > --- > > > > drivers/net/wireless/iwlwifi/iwl-trans-pcie.c | 3 +++ > > > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > > > > > diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c > > > b/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c > > > > index 60067c7..f69aecb 100644 > > > > --- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c > > > > +++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c > > > > @@ -406,6 +406,7 @@ static void iwl_tx_queue_unmap(struct iwl_trans > > > *trans, int txq_id) > > > > struct iwl_tx_queue *txq = &trans_pcie->txq[txq_id]; > > > > struct iwl_queue *q = &txq->q; > > > > enum dma_data_direction dma_dir; > > > > + unsigned long flags; > > > > > > > > if (!q->n_bd) > > > > return; > > > > @@ -418,12 +419,14 @@ static void iwl_tx_queue_unmap(struct iwl_trans > > > *trans, int txq_id) > > > > else > > > > dma_dir = DMA_TO_DEVICE; > > > > > > > > + spin_lock_irqsave(&trans->shrd->sta_lock, flags); > > > sta_lock does not look like right lock to use. > > > > > True. And I wrote in the commit message that this is a W/A until we > revamp the locking model. > > Why not simply take hcmd_lock? Hcmd_lock is related to the host command queue only, it won't work for Tx queues. --------------------------------------------------------------------- Intel Israel (74) Limited This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
