4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit c6ac9f9fb98851f47b978a9476594fc3c477a34d ]
Allocator swaps the pending requests with 0 when it starts working. This means that relying on it n RX path to decide if to move to emergency is not always a good idea, since it may be zero, but there are still a lot of unallocated RBs in the system. Change allocator to decrement the pending requests on real time. It is more expensive since it accesses the atomic variable more times, but it gives the RX path a better idea of the system's status.
Reported-by: Ilan Peer ilan.peer@intel.com Signed-off-by: Sara Sharon sara.sharon@intel.com Fixes: 868a1e863f95 ("iwlwifi: pcie: avoid empty free RB queue") Signed-off-by: Luca Coelho luciano.coelho@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c index e58a50d31d96..c21f8bd32d08 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c @@ -475,7 +475,7 @@ static void iwl_pcie_rx_allocator(struct iwl_trans *trans) struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans); struct iwl_rb_allocator *rba = &trans_pcie->rba; struct list_head local_empty; - int pending = atomic_xchg(&rba->req_pending, 0); + int pending = atomic_read(&rba->req_pending);
IWL_DEBUG_RX(trans, "Pending allocation requests = %d\n", pending);
@@ -530,11 +530,13 @@ static void iwl_pcie_rx_allocator(struct iwl_trans *trans) i++; }
+ atomic_dec(&rba->req_pending); pending--; + if (!pending) { - pending = atomic_xchg(&rba->req_pending, 0); + pending = atomic_read(&rba->req_pending); IWL_DEBUG_RX(trans, - "Pending allocation requests = %d\n", + "Got more pending allocation requests = %d\n", pending); }
@@ -546,12 +548,15 @@ static void iwl_pcie_rx_allocator(struct iwl_trans *trans) spin_unlock(&rba->lock);
atomic_inc(&rba->req_ready); + }
spin_lock(&rba->lock); /* return unused rbds to the allocator empty list */ list_splice_tail(&local_empty, &rba->rbd_empty); spin_unlock(&rba->lock); + + IWL_DEBUG_RX(trans, "%s, exit.\n", __func__); }
/*