Re: [PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE
On Sat, Nov 19, 2016 at 11:54:25AM -0800, Davidlohr Bueso wrote: > With the new standardized functions, we can replace all ACCESS_ONCE() > calls across relevant drivers/usb/. > > ACCESS_ONCE() does not work reliably on non-scalar types. For example > gcc 4.6 and 4.7 might remove the volatile tag for such accesses during > the SRA (scalar replacement of aggregates) step: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 > > Update the new calls regardless of if it is a scalar type, this is > cleaner than having three alternatives. > > Signed-off-by: Davidlohr Bueso Again, fix your From: line please.
Re: [PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE
On Sun, Nov 20, 2016 at 08:09:40AM -0800, Davidlohr Bueso wrote: > Hi Greg! > > On Sun, 20 Nov 2016, Greg KH wrote: > > > On Sat, Nov 19, 2016 at 11:54:25AM -0800, Davidlohr Bueso wrote: > > > With the new standardized functions, we can replace all ACCESS_ONCE() > > > calls across relevant drivers/usb/. > > > > > > ACCESS_ONCE() does not work reliably on non-scalar types. For example > > > gcc 4.6 and 4.7 might remove the volatile tag for such accesses during > > > the SRA (scalar replacement of aggregates) step: > > > > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 > > > > > > Update the new calls regardless of if it is a scalar type, this is > > > cleaner than having three alternatives. > > > > > > Signed-off-by: Davidlohr Bueso > > > > Nit, this doesn't match your From: line :( > > That's on purpose, and all my patches are the same. So they are all incorrect? Not good, why? You know this means I can't take them... > > If this is the case, why not just replacing the define for ACCESS_ONCE() > > with READ_ONCE() and then go back and just do a search/replace for the > > whole kernel all at once? > > So that we don't have three variants; the idea is to eventually > get rid of ACCESS_ONCE entirely. Then just get rid of it all at once. thanks, greg k-h
Re: [PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE
Hi Greg! On Sun, 20 Nov 2016, Greg KH wrote: On Sat, Nov 19, 2016 at 11:54:25AM -0800, Davidlohr Bueso wrote: With the new standardized functions, we can replace all ACCESS_ONCE() calls across relevant drivers/usb/. ACCESS_ONCE() does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 Update the new calls regardless of if it is a scalar type, this is cleaner than having three alternatives. Signed-off-by: Davidlohr Bueso Nit, this doesn't match your From: line :( That's on purpose, and all my patches are the same. If this is the case, why not just replacing the define for ACCESS_ONCE() with READ_ONCE() and then go back and just do a search/replace for the whole kernel all at once? So that we don't have three variants; the idea is to eventually get rid of ACCESS_ONCE entirely. Or just send Linus a patch for this all at once after -rc1 is out? No rush, whenever you see fit. Thanks, Davidlohr
Re: [PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE
On Sun, Nov 20, 2016 at 10:39:32AM +0100, Greg KH wrote: > On Sat, Nov 19, 2016 at 11:54:25AM -0800, Davidlohr Bueso wrote: > > With the new standardized functions, we can replace all ACCESS_ONCE() > > calls across relevant drivers/usb/. > > > > ACCESS_ONCE() does not work reliably on non-scalar types. For example > > gcc 4.6 and 4.7 might remove the volatile tag for such accesses during > > the SRA (scalar replacement of aggregates) step: > If this is the case, why not just replacing the define for ACCESS_ONCE() > with READ_ONCE() and then go back and just do a search/replace for the > whole kernel all at once? > > Or just send Linus a patch for this all at once after -rc1 is out? FWIW, I have a Coccinelle-generated patch for that [1]. ... there are a few cases where it doesn't quite work (e.g. formatting in the ath9k mac drivers), and I'm trying to put together a series [2] that fixes those cases up before leaving the bulk to Coccinelle. I hope to sort that out in the next few days. Thanks, Mark. [1] https://git.kernel.org/cgit/linux/kernel/git/mark/linux.git/commit/?h=core/access-once&id=7154d3cd5f2ddcc029d1afadc472c5720408d678 [2] https://git.kernel.org/cgit/linux/kernel/git/mark/linux.git/log/?h=core/access-once
Re: [PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE
On Sat, Nov 19, 2016 at 11:54:25AM -0800, Davidlohr Bueso wrote: > With the new standardized functions, we can replace all ACCESS_ONCE() > calls across relevant drivers/usb/. > > ACCESS_ONCE() does not work reliably on non-scalar types. For example > gcc 4.6 and 4.7 might remove the volatile tag for such accesses during > the SRA (scalar replacement of aggregates) step: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 > > Update the new calls regardless of if it is a scalar type, this is > cleaner than having three alternatives. > > Signed-off-by: Davidlohr Bueso Nit, this doesn't match your From: line :( If this is the case, why not just replacing the define for ACCESS_ONCE() with READ_ONCE() and then go back and just do a search/replace for the whole kernel all at once? Or just send Linus a patch for this all at once after -rc1 is out? thanks, greg k-h
[PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE
With the new standardized functions, we can replace all ACCESS_ONCE()
calls across relevant drivers/usb/.
ACCESS_ONCE() does not work reliably on non-scalar types. For example
gcc 4.6 and 4.7 might remove the volatile tag for such accesses during
the SRA (scalar replacement of aggregates) step:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145
Update the new calls regardless of if it is a scalar type, this is
cleaner than having three alternatives.
Signed-off-by: Davidlohr Bueso
---
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(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 0a6369510f2d..d31ae7d1c2ac 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -515,7 +515,7 @@ 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 4016dae7433b..ffd4389fb2e2 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -153,7 +153,7 @@ static int usbfs_increase_memory_usage(unsigned amount)
* Convert usbfs_memory_mb to bytes, avoiding overflows.
* 0 means use the hard limit (effectively unlimited).
*/
- lim = ACCESS_ONCE(usbfs_memory_mb);
+ lim = READ_ONCE(usbfs_memory_mb);
if (lim == 0 || lim > (USBFS_XFER_MAX >> 20))
lim = USBFS_XFER_MAX;
else
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index c953a0f1c695..048eece1884f 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -956,7 +956,7 @@ 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);
@@ -972,7 +972,7 @@ 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 39b7136d31d9..2af6e8a98224 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 86612ac3fda2..cf9ac6e3d157 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -784,7 +784,7 @@ 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 6f986d82472d..033a2b46a46e 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -184,7 +184,7 @@ 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))
@@ -272,7 +272,7 @@ struct uhci_td {
* subject to asynchronous updates by the control
