drivers: Remove explicit invocations of mmiowb()

mmiowb() is now implied by spin_unlock() on architectures that require
it, so there is no reason to call it from driver code. This patch was
generated using coccinelle:

	@mmiowb@
	@@
	- mmiowb();

and invoked as:

$ for d in drivers include/linux/qed sound; do \
spatch --include-headers --sp-file mmiowb.cocci --dir $d --in-place; done

NOTE: mmiowb() has only ever guaranteed ordering in conjunction with
spin_unlock(). However, pairing each mmiowb() removal in this patch with
the corresponding call to spin_unlock() is not at all trivial, so there
is a small chance that this change may regress any drivers incorrectly
relying on mmiowb() to order MMIO writes between CPUs using lock-free
synchronisation. If you've ended up bisecting to this commit, you can
reintroduce the mmiowb() calls using wmb() instead, which should restore
the old behaviour on all architectures other than some esoteric ia64
systems.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 0 insertions, 6 deletions

diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index a2351ef45ae0..65a4c142640d 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -837,7 +837,6 @@ ath5k_txbuf_setup(struct ath5k_hw *ah, struct ath5k_buf *bf,
 
 	txq->link = &ds->ds_link;
 	ath5k_hw_start_tx_dma(ah, txq->qnum);
-	mmiowb();
 	spin_unlock_bh(&txq->lock);
 
 	return 0;
@@ -2174,7 +2173,6 @@ ath5k_beacon_config(struct ath5k_hw *ah)
 	}
 
 	ath5k_hw_set_imr(ah, ah->imask);
-	mmiowb();
 	spin_unlock_bh(&ah->block);
 }
 
@@ -2779,7 +2777,6 @@ int ath5k_start(struct ieee80211_hw *hw)
 
 	ret = 0;
 done:
-	mmiowb();
 	mutex_unlock(&ah->lock);
 
 	set_bit(ATH_STAT_STARTED, ah->status);
@@ -2839,7 +2836,6 @@ void ath5k_stop(struct ieee80211_hw *hw)
 				"putting device to sleep\n");
 	}
 
-	mmiowb();
 	mutex_unlock(&ah->lock);
 
 	ath5k_stop_tasklets(ah);
diff --git a/drivers/net/wireless/ath/ath5k/mac80211-ops.c b/drivers/net/wireless/ath/ath5k/mac80211-ops.c
index 16e052d02c94..5e866a193ed0 100644
--- a/drivers/net/wireless/ath/ath5k/mac80211-ops.c
+++ b/drivers/net/wireless/ath/ath5k/mac80211-ops.c
@@ -263,7 +263,6 @@ ath5k_bss_info_changed(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		memcpy(common->curbssid, bss_conf->bssid, ETH_ALEN);
 		common->curaid = 0;
 		ath5k_hw_set_bssid(ah);
-		mmiowb();
 	}
 
 	if (changes & BSS_CHANGED_BEACON_INT)
@@ -528,7 +527,6 @@ ath5k_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 		ret = -EINVAL;
 	}
 
-	mmiowb();
 	mutex_unlock(&ah->lock);
 	return ret;
 }