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, 4 deletions

diff --git a/drivers/net/ethernet/sfc/falcon/io.h b/drivers/net/ethernet/sfc/falcon/io.h
index 7085ee1d5e2b..c3577643fbda 100644
--- a/drivers/net/ethernet/sfc/falcon/io.h
+++ b/drivers/net/ethernet/sfc/falcon/io.h
@@ -108,7 +108,6 @@ static inline void ef4_writeo(struct ef4_nic *efx, const ef4_oword_t *value,
 	_ef4_writed(efx, value->u32[2], reg + 8);
 	_ef4_writed(efx, value->u32[3], reg + 12);
 #endif
-	mmiowb();
 	spin_unlock_irqrestore(&efx->biu_lock, flags);
 }
 
@@ -130,7 +129,6 @@ static inline void ef4_sram_writeq(struct ef4_nic *efx, void __iomem *membase,
 	__raw_writel((__force u32)value->u32[0], membase + addr);
 	__raw_writel((__force u32)value->u32[1], membase + addr + 4);
 #endif
-	mmiowb();
 	spin_unlock_irqrestore(&efx->biu_lock, flags);
 }
 
diff --git a/drivers/net/ethernet/sfc/io.h b/drivers/net/ethernet/sfc/io.h
index 89563170af52..2774a10f44e9 100644
--- a/drivers/net/ethernet/sfc/io.h
+++ b/drivers/net/ethernet/sfc/io.h
@@ -120,7 +120,6 @@ static inline void efx_writeo(struct efx_nic *efx, const efx_oword_t *value,
 	_efx_writed(efx, value->u32[2], reg + 8);
 	_efx_writed(efx, value->u32[3], reg + 12);
 #endif
-	mmiowb();
 	spin_unlock_irqrestore(&efx->biu_lock, flags);
 }
 
@@ -142,7 +141,6 @@ static inline void efx_sram_writeq(struct efx_nic *efx, void __iomem *membase,
 	__raw_writel((__force u32)value->u32[0], membase + addr);
 	__raw_writel((__force u32)value->u32[1], membase + addr + 4);
 #endif
-	mmiowb();
 	spin_unlock_irqrestore(&efx->biu_lock, flags);
 }