From 6aa7de059173a986114ac43b8f50b297a86f09a8 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 23 Oct 2017 14:07:29 -0700 Subject: locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland Signed-off-by: Paul E. McKenney Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 2 +- drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 10 +++++----- 2 files changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/net/wireless/intel/iwlwifi/pcie') diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c index a06b6612b658..f25ce3a1ea50 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c @@ -1247,7 +1247,7 @@ restart: spin_lock(&rxq->lock); /* uCode's read index (stored in shared DRAM) indicates the last Rx * buffer that the driver may process (last buffer filled by ucode). */ - r = le16_to_cpu(ACCESS_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF; + r = le16_to_cpu(READ_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF; i = rxq->read; /* W/A 9000 device step A0 wrap-around bug */ diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c index 2e3e013ec95a..9ad3f4fe5894 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c @@ -2076,12 +2076,12 @@ static int iwl_trans_pcie_wait_txq_empty(struct iwl_trans *trans, int txq_idx) IWL_DEBUG_TX_QUEUES(trans, "Emptying queue %d...\n", txq_idx); txq = trans_pcie->txq[txq_idx]; - wr_ptr = ACCESS_ONCE(txq->write_ptr); + wr_ptr = READ_ONCE(txq->write_ptr); - while (txq->read_ptr != ACCESS_ONCE(txq->write_ptr) && + while (txq->read_ptr != READ_ONCE(txq->write_ptr) && !time_after(jiffies, now + msecs_to_jiffies(IWL_FLUSH_WAIT_MS))) { - u8 write_ptr = ACCESS_ONCE(txq->write_ptr); + u8 write_ptr = READ_ONCE(txq->write_ptr); if (WARN_ONCE(wr_ptr != write_ptr, "WR pointer moved while flushing %d -> %d\n", @@ -2553,7 +2553,7 @@ static u32 iwl_trans_pcie_dump_rbs(struct iwl_trans *trans, spin_lock(&rxq->lock); - r = le16_to_cpu(ACCESS_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF; + r = le16_to_cpu(READ_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF; for (i = rxq->read, j = 0; i != r && j < allocated_rb_nums; @@ -2814,7 +2814,7 @@ static struct iwl_trans_dump_data /* Dump RBs is supported only for pre-9000 devices (1 queue) */ struct iwl_rxq *rxq = &trans_pcie->rxq[0]; /* RBs */ - num_rbs = le16_to_cpu(ACCESS_ONCE(rxq->rb_stts->closed_rb_num)) + num_rbs = le16_to_cpu(READ_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF; num_rbs = (num_rbs - rxq->read) & RX_QUEUE_MASK; len += num_rbs * (sizeof(*data) + -- cgit v1.2.1