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/usb/class/cdc-wdm.c | 2 +- drivers/usb/core/devio.c | 2 +- drivers/usb/core/sysfs.c | 4 ++-- drivers/usb/gadget/udc/gr_udc.c | 4 ++-- drivers/usb/host/ohci-hcd.c | 2 +- drivers/usb/host/uhci-hcd.h | 4 ++-- 6 files changed, 9 insertions(+), 9 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 3e865dbf878c..fbaa2a90d25d 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -483,7 +483,7 @@ static ssize_t wdm_read if (rv < 0) return -ERESTARTSYS; - cntr = ACCESS_ONCE(desc->length); + cntr = READ_ONCE(desc->length); if (cntr == 0) { desc->read = 0; retry: diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index e9326f31db8d..4ae667d8c238 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -150,7 +150,7 @@ static int usbfs_increase_memory_usage(u64 amount) { u64 lim; - lim = ACCESS_ONCE(usbfs_memory_mb); + lim = READ_ONCE(usbfs_memory_mb); lim <<= 20; atomic64_add(amount, &usbfs_memory_usage); diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index d930bfda4010..58d59c5f8592 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -973,7 +973,7 @@ static ssize_t interface_show(struct device *dev, struct device_attribute *attr, char *string; intf = to_usb_interface(dev); - string = ACCESS_ONCE(intf->cur_altsetting->string); + string = READ_ONCE(intf->cur_altsetting->string); if (!string) return 0; return sprintf(buf, "%s\n", string); @@ -989,7 +989,7 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, intf = to_usb_interface(dev); udev = interface_to_usbdev(intf); - alt = ACCESS_ONCE(intf->cur_altsetting); + alt = READ_ONCE(intf->cur_altsetting); return sprintf(buf, "usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02X" "ic%02Xisc%02Xip%02Xin%02X\n", diff --git a/drivers/usb/gadget/udc/gr_udc.c b/drivers/usb/gadget/udc/gr_udc.c index 1f9941145746..0b59fa50aa30 100644 --- a/drivers/usb/gadget/udc/gr_udc.c +++ b/drivers/usb/gadget/udc/gr_udc.c @@ -1261,7 +1261,7 @@ static int gr_handle_in_ep(struct gr_ep *ep) if (!req->last_desc) return 0; - if (ACCESS_ONCE(req->last_desc->ctrl) & GR_DESC_IN_CTRL_EN) + if (READ_ONCE(req->last_desc->ctrl) & GR_DESC_IN_CTRL_EN) return 0; /* Not put in hardware buffers yet */ if (gr_read32(&ep->regs->epstat) & (GR_EPSTAT_B1 | GR_EPSTAT_B0)) @@ -1290,7 +1290,7 @@ static int gr_handle_out_ep(struct gr_ep *ep) if (!req->curr_desc) return 0; - ctrl = ACCESS_ONCE(req->curr_desc->ctrl); + ctrl = READ_ONCE(req->curr_desc->ctrl); if (ctrl & GR_DESC_OUT_CTRL_EN) return 0; /* Not received yet */ diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c index 44924824fa41..c86f89babd57 100644 --- a/drivers/usb/host/ohci-hcd.c +++ b/drivers/usb/host/ohci-hcd.c @@ -785,7 +785,7 @@ static void io_watchdog_func(unsigned long _ohci) } /* find the last TD processed by the controller. */ - head = hc32_to_cpu(ohci, ACCESS_ONCE(ed->hwHeadP)) & TD_MASK; + head = hc32_to_cpu(ohci, READ_ONCE(ed->hwHeadP)) & TD_MASK; td_start = td; td_next = list_prepare_entry(td, &ed->td_list, td_list); list_for_each_entry_continue(td_next, &ed->td_list, td_list) { diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h index 91b22b2ea3aa..09a2a259941b 100644 --- a/drivers/usb/host/uhci-hcd.h +++ b/drivers/usb/host/uhci-hcd.h @@ -186,7 +186,7 @@ struct uhci_qh { * We need a special accessor for the element pointer because it is * subject to asynchronous updates by the controller. */ -#define qh_element(qh) ACCESS_ONCE((qh)->element) +#define qh_element(qh) READ_ONCE((qh)->element) #define LINK_TO_QH(uhci, qh) (UHCI_PTR_QH((uhci)) | \ cpu_to_hc32((uhci), (qh)->dma_handle)) @@ -274,7 +274,7 @@ struct uhci_td { * subject to asynchronous updates by the controller. */ #define td_status(uhci, td) hc32_to_cpu((uhci), \ - ACCESS_ONCE((td)->status)) + READ_ONCE((td)->status)) #define LINK_TO_TD(uhci, td) (cpu_to_hc32((uhci), (td)->dma_handle)) -- cgit v1.2.3