diff options
| author |   Will Deacon <will.deacon@arm.com> | 2019-02-22 17:14:59 +0000 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2019-04-08 12:01:02 +0100 |
| commit | fb24ea52f78e0d595852e09e3a55697c8f442189 (patch) | |
| tree | 00ca29c7b0b8df6258a1ad1faf34f6e838ada26c /drivers/net/ethernet/qlogic/qede | |
| parent | drivers: Remove useless trailing comments from mmiowb() invocations (diff) | |
| download | linux-dev-fb24ea52f78e0d595852e09e3a55697c8f442189.tar.xz linux-dev-fb24ea52f78e0d595852e09e3a55697c8f442189.zip | |
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>
Diffstat (limited to 'drivers/net/ethernet/qlogic/qede')
| -rw-r--r-- | drivers/net/ethernet/qlogic/qede/qede_ethtool.c | 8 | ||||
| -rw-r--r-- | drivers/net/ethernet/qlogic/qede/qede_fp.c | 8 |
2 files changed, 0 insertions, 16 deletions
diff --git a/drivers/net/ethernet/qlogic/qede/qede_ethtool.c b/drivers/net/ethernet/qlogic/qede/qede_ethtool.c index b4c8949933f1..4555c0b161ef 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_ethtool.c +++ b/drivers/net/ethernet/qlogic/qede/qede_ethtool.c @@ -1526,14 +1526,6 @@ static int qede_selftest_transmit_traffic(struct qede_dev *edev, barrier(); writel(txq->tx_db.raw, txq->doorbell_addr); - /* mmiowb is needed to synchronize doorbell writes from more than one - * processor. It guarantees that the write arrives to the device before - * the queue lock is released and another start_xmit is called (possibly - * on another CPU). Without this barrier, the next doorbell can bypass - * this doorbell. This is applicable to IA64/Altix systems. - */ - mmiowb(); - for (i = 0; i < QEDE_SELFTEST_POLL_COUNT; i++) { if (qede_txq_has_work(txq)) break; diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c index 31b046e24565..6f7e3622c6b4 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_fp.c +++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c @@ -580,14 +580,6 @@ void qede_update_rx_prod(struct qede_dev *edev, struct qede_rx_queue *rxq) internal_ram_wr(rxq->hw_rxq_prod_addr, sizeof(rx_prods), (u32 *)&rx_prods); - - /* mmiowb is needed to synchronize doorbell writes from more than one - * processor. It guarantees that the write arrives to the device before - * the napi lock is released and another qede_poll is called (possibly - * on another CPU). Without this barrier, the next doorbell can bypass - * this doorbell. This is applicable to IA64/Altix systems. - */ - mmiowb(); } static void qede_get_rxhash(struct sk_buff *skb, u8 bitfields, __le32 rss_hash) |