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/ethernet/sfc/ptp.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/net/ethernet/sfc/ptp.c') diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c index 60cdb97f58e2..56c2db398def 100644 --- a/drivers/net/ethernet/sfc/ptp.c +++ b/drivers/net/ethernet/sfc/ptp.c @@ -658,7 +658,7 @@ static void efx_ptp_send_times(struct efx_nic *efx, /* Write host time for specified period or until MC is done */ while ((timespec64_compare(&now.ts_real, &limit) < 0) && - ACCESS_ONCE(*mc_running)) { + READ_ONCE(*mc_running)) { struct timespec64 update_time; unsigned int host_time; @@ -668,7 +668,7 @@ static void efx_ptp_send_times(struct efx_nic *efx, do { pps_get_ts(&now); } while ((timespec64_compare(&now.ts_real, &update_time) < 0) && - ACCESS_ONCE(*mc_running)); + READ_ONCE(*mc_running)); /* Synchronise NIC with single word of time only */ host_time = (now.ts_real.tv_sec << MC_NANOSECOND_BITS | @@ -832,14 +832,14 @@ static int efx_ptp_synchronize(struct efx_nic *efx, unsigned int num_readings) ptp->start.dma_addr); /* Clear flag that signals MC ready */ - ACCESS_ONCE(*start) = 0; + WRITE_ONCE(*start, 0); rc = efx_mcdi_rpc_start(efx, MC_CMD_PTP, synch_buf, MC_CMD_PTP_IN_SYNCHRONIZE_LEN); EFX_WARN_ON_ONCE_PARANOID(rc); /* Wait for start from MCDI (or timeout) */ timeout = jiffies + msecs_to_jiffies(MAX_SYNCHRONISE_WAIT_MS); - while (!ACCESS_ONCE(*start) && (time_before(jiffies, timeout))) { + while (!READ_ONCE(*start) && (time_before(jiffies, timeout))) { udelay(20); /* Usually start MCDI execution quickly */ loops++; } @@ -849,7 +849,7 @@ static int efx_ptp_synchronize(struct efx_nic *efx, unsigned int num_readings) if (!time_before(jiffies, timeout)) ++ptp->sync_timeouts; - if (ACCESS_ONCE(*start)) + if (READ_ONCE(*start)) efx_ptp_send_times(efx, &last_time); /* Collect results */ -- cgit v1.2.3-58-ga151