PCI/PM: Fix proc config reg access for D3cold and bridge suspending

In https://bugzilla.kernel.org/show_bug.cgi?id=48981
Peter reported that /proc/bus/pci/??/??.? does not work for 3.6.
This is because the device configuration space registers are
not accessible if the corresponding parent bridge is suspended or
the device is put into D3cold state.

This is the same as /sys/bus/pci/devices/0000:??:??.?/config access
issue.  So the function used to solve sysfs issue is used to solve
this issue.

This patch moves pci_config_pm_runtime_get()/_put() from pci/pci-sysfs.c
to pci/pci.c and makes them extern so they can be used by both the
sysfs and proc paths.

[bhelgaas: changelog, references, reporters]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=48981
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=49031
Reported-by: Forrest Loomis <cybercyst@gmail.com>
Reported-by: Peter <lekensteyn@gmail.com>
Reported-by: Micael Dias <kam1kaz3@gmail.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: stable@vger.kernel.org		# v3.6+

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 02d107b152818e948cc3e561d276bf24126ac997..f39378d9da1500056a90f4816f742e9e5ee9626f 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -458,40 +458,6 @@ boot_vga_show(struct device *dev, struct device_attribute *attr, char *buf)
 }
 struct device_attribute vga_attr = __ATTR_RO(boot_vga);
 
-static void
-pci_config_pm_runtime_get(struct pci_dev *pdev)
-{
-       struct device *dev = &pdev->dev;
-       struct device *parent = dev->parent;
-
-       if (parent)
-               pm_runtime_get_sync(parent);
-       pm_runtime_get_noresume(dev);
-       /*
-        * pdev->current_state is set to PCI_D3cold during suspending,
-        * so wait until suspending completes
-        */
-       pm_runtime_barrier(dev);
-       /*
-        * Only need to resume devices in D3cold, because config
-        * registers are still accessible for devices suspended but
-        * not in D3cold.
-        */
-       if (pdev->current_state == PCI_D3cold)
-               pm_runtime_resume(dev);
-}
-
-static void
-pci_config_pm_runtime_put(struct pci_dev *pdev)
-{
-       struct device *dev = &pdev->dev;
-       struct device *parent = dev->parent;
-
-       pm_runtime_put(dev);
-       if (parent)
-               pm_runtime_put_sync(parent);
-}
-
 static ssize_t
 pci_read_config(struct file *filp, struct kobject *kobj,
                struct bin_attribute *bin_attr,

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 54858838f09867f142886edcac6b4dab9c049531..aabf64798bda7d2ebdca2697f23c7e29bfbae620 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1858,6 +1858,38 @@ bool pci_dev_run_wake(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_dev_run_wake);
 
+void pci_config_pm_runtime_get(struct pci_dev *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device *parent = dev->parent;
+
+       if (parent)
+               pm_runtime_get_sync(parent);
+       pm_runtime_get_noresume(dev);
+       /*
+        * pdev->current_state is set to PCI_D3cold during suspending,
+        * so wait until suspending completes
+        */
+       pm_runtime_barrier(dev);
+       /*
+        * Only need to resume devices in D3cold, because config
+        * registers are still accessible for devices suspended but
+        * not in D3cold.
+        */
+       if (pdev->current_state == PCI_D3cold)
+               pm_runtime_resume(dev);
+}
+
+void pci_config_pm_runtime_put(struct pci_dev *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device *parent = dev->parent;
+
+       pm_runtime_put(dev);
+       if (parent)
+               pm_runtime_put_sync(parent);
+}
+
 /**
  * pci_pm_init - Initialize PM functions of given PCI device
  * @dev: PCI device to handle.

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index bacbcba69cf386dd2971b8b94e6ddd383888b471..fd92aab9904b92a694dadf685291220121661905 100644 (file)
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -72,6 +72,8 @@ extern void pci_disable_enabled_device(struct pci_dev *dev);
 extern int pci_finish_runtime_suspend(struct pci_dev *dev);
 extern int __pci_pme_wakeup(struct pci_dev *dev, void *ign);
 extern void pci_wakeup_bus(struct pci_bus *bus);
+extern void pci_config_pm_runtime_get(struct pci_dev *dev);
+extern void pci_config_pm_runtime_put(struct pci_dev *dev);
 extern void pci_pm_init(struct pci_dev *dev);
 extern void platform_pci_wakeup_init(struct pci_dev *dev);
 extern void pci_allocate_cap_save_buffers(struct pci_dev *dev);

diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
index eb907a8faf2a9b6e325033005127b0b40904930a..9b8505ccc56d5ef87a09105f5847d19a441ec704 100644 (file)
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -76,6 +76,8 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
        if (!access_ok(VERIFY_WRITE, buf, cnt))
                return -EINVAL;
 
+       pci_config_pm_runtime_get(dev);
+
        if ((pos & 1) && cnt) {
                unsigned char val;
                pci_user_read_config_byte(dev, pos, &val);
@@ -121,6 +123,8 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
                cnt--;
        }
 
+       pci_config_pm_runtime_put(dev);
+
        *ppos = pos;
        return nbytes;
 }
@@ -146,6 +150,8 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
        if (!access_ok(VERIFY_READ, buf, cnt))
                return -EINVAL;
 
+       pci_config_pm_runtime_get(dev);
+
        if ((pos & 1) && cnt) {
                unsigned char val;
                __get_user(val, buf);
@@ -191,6 +197,8 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
                cnt--;
        }
 
+       pci_config_pm_runtime_put(dev);
+
        *ppos = pos;
        i_size_write(ino, dp->size);
        return nbytes;