| Message ID | 20220227135214.145599-2-krzysztof.kozlowski@canonical.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix broken usage of driver_override (and kfree of static memory) | expand |
On 22-02-27 14:52:04, Krzysztof Kozlowski wrote: > Several core drivers and buses expect that driver_override is a > dynamically allocated memory thus later they can kfree() it. > > However such assumption is not documented, there were in the past and > there are already users setting it to a string literal. This leads to > kfree() of static memory during device release (e.g. in error paths or > during unbind): > > kernel BUG at ../mm/slub.c:3960! > Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM > ... > (kfree) from [<c058da50>] (platform_device_release+0x88/0xb4) > (platform_device_release) from [<c0585be0>] (device_release+0x2c/0x90) > (device_release) from [<c0a69050>] (kobject_put+0xec/0x20c) > (kobject_put) from [<c0f2f120>] (exynos5_clk_probe+0x154/0x18c) > (exynos5_clk_probe) from [<c058de70>] (platform_drv_probe+0x6c/0xa4) > (platform_drv_probe) from [<c058b7ac>] (really_probe+0x280/0x414) > (really_probe) from [<c058baf4>] (driver_probe_device+0x78/0x1c4) > (driver_probe_device) from [<c0589854>] (bus_for_each_drv+0x74/0xb8) > (bus_for_each_drv) from [<c058b48c>] (__device_attach+0xd4/0x16c) > (__device_attach) from [<c058a638>] (bus_probe_device+0x88/0x90) > (bus_probe_device) from [<c05871fc>] (device_add+0x3dc/0x62c) > (device_add) from [<c075ff10>] (of_platform_device_create_pdata+0x94/0xbc) > (of_platform_device_create_pdata) from [<c07600ec>] (of_platform_bus_create+0x1a8/0x4fc) > (of_platform_bus_create) from [<c0760150>] (of_platform_bus_create+0x20c/0x4fc) > (of_platform_bus_create) from [<c07605f0>] (of_platform_populate+0x84/0x118) > (of_platform_populate) from [<c0f3c964>] (of_platform_default_populate_init+0xa0/0xb8) > (of_platform_default_populate_init) from [<c01031f8>] (do_one_initcall+0x8c/0x404) > (do_one_initcall) from [<c0f012c0>] (kernel_init_freeable+0x3d0/0x4d8) > (kernel_init_freeable) from [<c0a7def0>] (kernel_init+0x8/0x114) > (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20) > > Provide a helper which clearly documents the usage of driver_override. > This will allow later to reuse the helper and reduce amount of > duplicated code. > > Convert the platform driver to use new helper and make the > driver_override field const char (it is not modified by the core). > > Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> > --- > drivers/base/driver.c | 51 +++++++++++++++++++++++++++++++++ > drivers/base/platform.c | 28 +++--------------- > include/linux/device/driver.h | 2 ++ > include/linux/platform_device.h | 7 ++++- > 4 files changed, 63 insertions(+), 25 deletions(-) > > diff --git a/drivers/base/driver.c b/drivers/base/driver.c > index 8c0d33e182fd..353750b0bbc5 100644 > --- a/drivers/base/driver.c > +++ b/drivers/base/driver.c > @@ -30,6 +30,57 @@ static struct device *next_device(struct klist_iter *i) > return dev; > } > > +/** > + * driver_set_override() - Helper to set or clear driver override. > + * @dev: Device to change > + * @override: Address of string to change (e.g. &device->driver_override); > + * The contents will be freed and hold newly allocated override. > + * @s: NUL terminated string, new driver name to force a match, pass empty > + * string to clear it > + * @len: length of @s > + * > + * Helper to set or clear driver override in a device, intended for the cases > + * when the driver_override field is allocated by driver/bus code. > + * > + * Returns: 0 on success or a negative error code on failure. > + */ > +int driver_set_override(struct device *dev, const char **override, > + const char *s, size_t len) TBH, I think it would make more sense to have this generic driver_set_override receive only the dev and the string. And then, each bus type will have their own implementation that handle things their own way. This would allow all the drivers that will use this to do something like this: ret = driver_set_override(&pdev->dev, "override_string"); I think it would look more cleaner. > +{ > + const char *new, *old; > + char *cp; > + > + if (!dev || !override || !s) > + return -EINVAL; > + > + /* We need to keep extra room for a newline */ > + if (len >= (PAGE_SIZE - 1)) > + return -EINVAL; > + > + new = kstrndup(s, len, GFP_KERNEL); > + if (!new) > + return -ENOMEM; > + > + cp = strchr(new, '\n'); > + if (cp) > + *cp = '\0'; > + > + device_lock(dev); > + old = *override; > + if (cp != new) { > + *override = new; > + } else { > + kfree(new); > + *override = NULL; > + } > + device_unlock(dev); > + > + kfree(old); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(driver_set_override); > + > /** > * driver_for_each_device - Iterator for devices bound to a driver. > * @drv: Driver we're iterating. > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index 6cb04ac48bf0..8dd87f44bd74 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -1275,31 +1275,11 @@ static ssize_t driver_override_store(struct device *dev, > const char *buf, size_t count) > { > struct platform_device *pdev = to_platform_device(dev); > - char *driver_override, *old, *cp; > - > - /* We need to keep extra room for a newline */ > - if (count >= (PAGE_SIZE - 1)) > - return -EINVAL; > - > - driver_override = kstrndup(buf, count, GFP_KERNEL); > - if (!driver_override) > - return -ENOMEM; > - > - cp = strchr(driver_override, '\n'); > - if (cp) > - *cp = '\0'; > - > - device_lock(dev); > - old = pdev->driver_override; > - if (strlen(driver_override)) { > - pdev->driver_override = driver_override; > - } else { > - kfree(driver_override); > - pdev->driver_override = NULL; > - } > - device_unlock(dev); > + int ret; > > - kfree(old); > + ret = driver_set_override(dev, &pdev->driver_override, buf, count); > + if (ret) > + return ret; > > return count; > } > diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h > index 15e7c5e15d62..700453017e1c 100644 > --- a/include/linux/device/driver.h > +++ b/include/linux/device/driver.h > @@ -151,6 +151,8 @@ extern int __must_check driver_create_file(struct device_driver *driver, > extern void driver_remove_file(struct device_driver *driver, > const struct driver_attribute *attr); > > +int driver_set_override(struct device *dev, const char **override, > + const char *s, size_t len); > extern int __must_check driver_for_each_device(struct device_driver *drv, > struct device *start, > void *data, > diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h > index 7c96f169d274..e39963889aa3 100644 > --- a/include/linux/platform_device.h > +++ b/include/linux/platform_device.h > @@ -31,7 +31,12 @@ struct platform_device { > struct resource *resource; > > const struct platform_device_id *id_entry; > - char *driver_override; /* Driver name to force a match */ > + /* > + * Driver name to force a match. > + * Do not set directly, because core frees it. > + * Use driver_set_override() to set or clear it. > + */ > + const char *driver_override; > > /* MFD cell pointer */ > struct mfd_cell *mfd_cell; > -- > 2.32.0 >
On 28/02/2022 11:51, Abel Vesa wrote: > On 22-02-27 14:52:04, Krzysztof Kozlowski wrote: >> Several core drivers and buses expect that driver_override is a >> dynamically allocated memory thus later they can kfree() it. >> >> However such assumption is not documented, there were in the past and >> there are already users setting it to a string literal. This leads to >> kfree() of static memory during device release (e.g. in error paths or >> during unbind): >> >> kernel BUG at ../mm/slub.c:3960! >> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM >> ... >> (kfree) from [<c058da50>] (platform_device_release+0x88/0xb4) >> (platform_device_release) from [<c0585be0>] (device_release+0x2c/0x90) >> (device_release) from [<c0a69050>] (kobject_put+0xec/0x20c) >> (kobject_put) from [<c0f2f120>] (exynos5_clk_probe+0x154/0x18c) >> (exynos5_clk_probe) from [<c058de70>] (platform_drv_probe+0x6c/0xa4) >> (platform_drv_probe) from [<c058b7ac>] (really_probe+0x280/0x414) >> (really_probe) from [<c058baf4>] (driver_probe_device+0x78/0x1c4) >> (driver_probe_device) from [<c0589854>] (bus_for_each_drv+0x74/0xb8) >> (bus_for_each_drv) from [<c058b48c>] (__device_attach+0xd4/0x16c) >> (__device_attach) from [<c058a638>] (bus_probe_device+0x88/0x90) >> (bus_probe_device) from [<c05871fc>] (device_add+0x3dc/0x62c) >> (device_add) from [<c075ff10>] (of_platform_device_create_pdata+0x94/0xbc) >> (of_platform_device_create_pdata) from [<c07600ec>] (of_platform_bus_create+0x1a8/0x4fc) >> (of_platform_bus_create) from [<c0760150>] (of_platform_bus_create+0x20c/0x4fc) >> (of_platform_bus_create) from [<c07605f0>] (of_platform_populate+0x84/0x118) >> (of_platform_populate) from [<c0f3c964>] (of_platform_default_populate_init+0xa0/0xb8) >> (of_platform_default_populate_init) from [<c01031f8>] (do_one_initcall+0x8c/0x404) >> (do_one_initcall) from [<c0f012c0>] (kernel_init_freeable+0x3d0/0x4d8) >> (kernel_init_freeable) from [<c0a7def0>] (kernel_init+0x8/0x114) >> (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20) >> >> Provide a helper which clearly documents the usage of driver_override. >> This will allow later to reuse the helper and reduce amount of >> duplicated code. >> >> Convert the platform driver to use new helper and make the >> driver_override field const char (it is not modified by the core). >> >> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> >> --- >> drivers/base/driver.c | 51 +++++++++++++++++++++++++++++++++ >> drivers/base/platform.c | 28 +++--------------- >> include/linux/device/driver.h | 2 ++ >> include/linux/platform_device.h | 7 ++++- >> 4 files changed, 63 insertions(+), 25 deletions(-) >> >> diff --git a/drivers/base/driver.c b/drivers/base/driver.c >> index 8c0d33e182fd..353750b0bbc5 100644 >> --- a/drivers/base/driver.c >> +++ b/drivers/base/driver.c >> @@ -30,6 +30,57 @@ static struct device *next_device(struct klist_iter *i) >> return dev; >> } >> >> +/** >> + * driver_set_override() - Helper to set or clear driver override. >> + * @dev: Device to change >> + * @override: Address of string to change (e.g. &device->driver_override); >> + * The contents will be freed and hold newly allocated override. >> + * @s: NUL terminated string, new driver name to force a match, pass empty >> + * string to clear it >> + * @len: length of @s >> + * >> + * Helper to set or clear driver override in a device, intended for the cases >> + * when the driver_override field is allocated by driver/bus code. >> + * >> + * Returns: 0 on success or a negative error code on failure. >> + */ >> +int driver_set_override(struct device *dev, const char **override, >> + const char *s, size_t len) > > TBH, I think it would make more sense to have this generic > driver_set_override receive only the dev and the string. And then, > each bus type will have their own implementation that handle things > their own way. This would allow all the drivers that will use this to > do something like this: > > ret = driver_set_override(&pdev->dev, "override_string"); > > I think it would look more cleaner. > The interface in general is not for the drivers. Drivers use it in exceptions (few cases in entire kernel) but many times they actually do not need to. Adding a dedicated driver_set_override() brings intention that such usage is welcomed... but it's not. :) Best regards, Krzysztof
On 22-02-28 12:30:45, Krzysztof Kozlowski wrote: > On 28/02/2022 11:51, Abel Vesa wrote: > > On 22-02-27 14:52:04, Krzysztof Kozlowski wrote: > >> Several core drivers and buses expect that driver_override is a > >> dynamically allocated memory thus later they can kfree() it. > >> > >> However such assumption is not documented, there were in the past and > >> there are already users setting it to a string literal. This leads to > >> kfree() of static memory during device release (e.g. in error paths or > >> during unbind): > >> > >> kernel BUG at ../mm/slub.c:3960! > >> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM > >> ... > >> (kfree) from [<c058da50>] (platform_device_release+0x88/0xb4) > >> (platform_device_release) from [<c0585be0>] (device_release+0x2c/0x90) > >> (device_release) from [<c0a69050>] (kobject_put+0xec/0x20c) > >> (kobject_put) from [<c0f2f120>] (exynos5_clk_probe+0x154/0x18c) > >> (exynos5_clk_probe) from [<c058de70>] (platform_drv_probe+0x6c/0xa4) > >> (platform_drv_probe) from [<c058b7ac>] (really_probe+0x280/0x414) > >> (really_probe) from [<c058baf4>] (driver_probe_device+0x78/0x1c4) > >> (driver_probe_device) from [<c0589854>] (bus_for_each_drv+0x74/0xb8) > >> (bus_for_each_drv) from [<c058b48c>] (__device_attach+0xd4/0x16c) > >> (__device_attach) from [<c058a638>] (bus_probe_device+0x88/0x90) > >> (bus_probe_device) from [<c05871fc>] (device_add+0x3dc/0x62c) > >> (device_add) from [<c075ff10>] (of_platform_device_create_pdata+0x94/0xbc) > >> (of_platform_device_create_pdata) from [<c07600ec>] (of_platform_bus_create+0x1a8/0x4fc) > >> (of_platform_bus_create) from [<c0760150>] (of_platform_bus_create+0x20c/0x4fc) > >> (of_platform_bus_create) from [<c07605f0>] (of_platform_populate+0x84/0x118) > >> (of_platform_populate) from [<c0f3c964>] (of_platform_default_populate_init+0xa0/0xb8) > >> (of_platform_default_populate_init) from [<c01031f8>] (do_one_initcall+0x8c/0x404) > >> (do_one_initcall) from [<c0f012c0>] (kernel_init_freeable+0x3d0/0x4d8) > >> (kernel_init_freeable) from [<c0a7def0>] (kernel_init+0x8/0x114) > >> (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20) > >> > >> Provide a helper which clearly documents the usage of driver_override. > >> This will allow later to reuse the helper and reduce amount of > >> duplicated code. > >> > >> Convert the platform driver to use new helper and make the > >> driver_override field const char (it is not modified by the core). > >> > >> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> > >> --- > >> drivers/base/driver.c | 51 +++++++++++++++++++++++++++++++++ > >> drivers/base/platform.c | 28 +++--------------- > >> include/linux/device/driver.h | 2 ++ > >> include/linux/platform_device.h | 7 ++++- > >> 4 files changed, 63 insertions(+), 25 deletions(-) > >> > >> diff --git a/drivers/base/driver.c b/drivers/base/driver.c > >> index 8c0d33e182fd..353750b0bbc5 100644 > >> --- a/drivers/base/driver.c > >> +++ b/drivers/base/driver.c > >> @@ -30,6 +30,57 @@ static struct device *next_device(struct klist_iter *i) > >> return dev; > >> } > >> > >> +/** > >> + * driver_set_override() - Helper to set or clear driver override. > >> + * @dev: Device to change > >> + * @override: Address of string to change (e.g. &device->driver_override); > >> + * The contents will be freed and hold newly allocated override. > >> + * @s: NUL terminated string, new driver name to force a match, pass empty > >> + * string to clear it > >> + * @len: length of @s > >> + * > >> + * Helper to set or clear driver override in a device, intended for the cases > >> + * when the driver_override field is allocated by driver/bus code. > >> + * > >> + * Returns: 0 on success or a negative error code on failure. > >> + */ > >> +int driver_set_override(struct device *dev, const char **override, > >> + const char *s, size_t len) > > > > TBH, I think it would make more sense to have this generic > > driver_set_override receive only the dev and the string. And then, > > each bus type will have their own implementation that handle things > > their own way. This would allow all the drivers that will use this to > > do something like this: > > > > ret = driver_set_override(&pdev->dev, "override_string"); > > > > I think it would look more cleaner. > > > > The interface in general is not for the drivers. Drivers use it in > exceptions (few cases in entire kernel) but many times they actually do > not need to. > > Adding a dedicated driver_set_override() brings intention that such > usage is welcomed... but it's not. :) I understand that. Anyway, I was more focused on this looking cleaner. But I'll let the others weigh in on this before applying the imx clk patch. Thanks. > > > Best regards, > Krzysztof
On Sun, Feb 27, 2022 at 02:52:04PM +0100, Krzysztof Kozlowski wrote: > Several core drivers and buses expect that driver_override is a > dynamically allocated memory thus later they can kfree() it. > +int driver_set_override(struct device *dev, const char **override, > + const char *s, size_t len) > +{ > + const char *new, *old; > + char *cp; > + > + if (!dev || !override || !s) > + return -EINVAL; > + > + /* We need to keep extra room for a newline */ It would help a lot to extend this comment with a hint about where the room for a newline is needed. It was confusing even before, but it's much more so now that the check is in a completely different file than the "show" functions that need the space. > + if (len >= (PAGE_SIZE - 1)) > + return -EINVAL;
On 28/02/2022 21:03, Bjorn Helgaas wrote: > On Sun, Feb 27, 2022 at 02:52:04PM +0100, Krzysztof Kozlowski wrote: >> Several core drivers and buses expect that driver_override is a >> dynamically allocated memory thus later they can kfree() it. > >> +int driver_set_override(struct device *dev, const char **override, >> + const char *s, size_t len) >> +{ >> + const char *new, *old; >> + char *cp; >> + >> + if (!dev || !override || !s) >> + return -EINVAL; >> + >> + /* We need to keep extra room for a newline */ > > It would help a lot to extend this comment with a hint about where the > room for a newline is needed. It was confusing even before, but it's > much more so now that the check is in a completely different file than > the "show" functions that need the space. > Indeed, this needs explanation. Best regards, Krzysztof
diff --git a/drivers/base/driver.c b/drivers/base/driver.c index 8c0d33e182fd..353750b0bbc5 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -30,6 +30,57 @@ static struct device *next_device(struct klist_iter *i) return dev; } +/** + * driver_set_override() - Helper to set or clear driver override. + * @dev: Device to change + * @override: Address of string to change (e.g. &device->driver_override); + * The contents will be freed and hold newly allocated override. + * @s: NUL terminated string, new driver name to force a match, pass empty + * string to clear it + * @len: length of @s + * + * Helper to set or clear driver override in a device, intended for the cases + * when the driver_override field is allocated by driver/bus code. + * + * Returns: 0 on success or a negative error code on failure. + */ +int driver_set_override(struct device *dev, const char **override, + const char *s, size_t len) +{ + const char *new, *old; + char *cp; + + if (!dev || !override || !s) + return -EINVAL; + + /* We need to keep extra room for a newline */ + if (len >= (PAGE_SIZE - 1)) + return -EINVAL; + + new = kstrndup(s, len, GFP_KERNEL); + if (!new) + return -ENOMEM; + + cp = strchr(new, '\n'); + if (cp) + *cp = '\0'; + + device_lock(dev); + old = *override; + if (cp != new) { + *override = new; + } else { + kfree(new); + *override = NULL; + } + device_unlock(dev); + + kfree(old); + + return 0; +} +EXPORT_SYMBOL_GPL(driver_set_override); + /** * driver_for_each_device - Iterator for devices bound to a driver. * @drv: Driver we're iterating. diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 6cb04ac48bf0..8dd87f44bd74 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -1275,31 +1275,11 @@ static ssize_t driver_override_store(struct device *dev, const char *buf, size_t count) { struct platform_device *pdev = to_platform_device(dev); - char *driver_override, *old, *cp; - - /* We need to keep extra room for a newline */ - if (count >= (PAGE_SIZE - 1)) - return -EINVAL; - - driver_override = kstrndup(buf, count, GFP_KERNEL); - if (!driver_override) - return -ENOMEM; - - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - - device_lock(dev); - old = pdev->driver_override; - if (strlen(driver_override)) { - pdev->driver_override = driver_override; - } else { - kfree(driver_override); - pdev->driver_override = NULL; - } - device_unlock(dev); + int ret; - kfree(old); + ret = driver_set_override(dev, &pdev->driver_override, buf, count); + if (ret) + return ret; return count; } diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h index 15e7c5e15d62..700453017e1c 100644 --- a/include/linux/device/driver.h +++ b/include/linux/device/driver.h @@ -151,6 +151,8 @@ extern int __must_check driver_create_file(struct device_driver *driver, extern void driver_remove_file(struct device_driver *driver, const struct driver_attribute *attr); +int driver_set_override(struct device *dev, const char **override, + const char *s, size_t len); extern int __must_check driver_for_each_device(struct device_driver *drv, struct device *start, void *data, diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index 7c96f169d274..e39963889aa3 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -31,7 +31,12 @@ struct platform_device { struct resource *resource; const struct platform_device_id *id_entry; - char *driver_override; /* Driver name to force a match */ + /* + * Driver name to force a match. + * Do not set directly, because core frees it. + * Use driver_set_override() to set or clear it. + */ + const char *driver_override; /* MFD cell pointer */ struct mfd_cell *mfd_cell;
Several core drivers and buses expect that driver_override is a dynamically allocated memory thus later they can kfree() it. However such assumption is not documented, there were in the past and there are already users setting it to a string literal. This leads to kfree() of static memory during device release (e.g. in error paths or during unbind): kernel BUG at ../mm/slub.c:3960! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM ... (kfree) from [<c058da50>] (platform_device_release+0x88/0xb4) (platform_device_release) from [<c0585be0>] (device_release+0x2c/0x90) (device_release) from [<c0a69050>] (kobject_put+0xec/0x20c) (kobject_put) from [<c0f2f120>] (exynos5_clk_probe+0x154/0x18c) (exynos5_clk_probe) from [<c058de70>] (platform_drv_probe+0x6c/0xa4) (platform_drv_probe) from [<c058b7ac>] (really_probe+0x280/0x414) (really_probe) from [<c058baf4>] (driver_probe_device+0x78/0x1c4) (driver_probe_device) from [<c0589854>] (bus_for_each_drv+0x74/0xb8) (bus_for_each_drv) from [<c058b48c>] (__device_attach+0xd4/0x16c) (__device_attach) from [<c058a638>] (bus_probe_device+0x88/0x90) (bus_probe_device) from [<c05871fc>] (device_add+0x3dc/0x62c) (device_add) from [<c075ff10>] (of_platform_device_create_pdata+0x94/0xbc) (of_platform_device_create_pdata) from [<c07600ec>] (of_platform_bus_create+0x1a8/0x4fc) (of_platform_bus_create) from [<c0760150>] (of_platform_bus_create+0x20c/0x4fc) (of_platform_bus_create) from [<c07605f0>] (of_platform_populate+0x84/0x118) (of_platform_populate) from [<c0f3c964>] (of_platform_default_populate_init+0xa0/0xb8) (of_platform_default_populate_init) from [<c01031f8>] (do_one_initcall+0x8c/0x404) (do_one_initcall) from [<c0f012c0>] (kernel_init_freeable+0x3d0/0x4d8) (kernel_init_freeable) from [<c0a7def0>] (kernel_init+0x8/0x114) (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20) Provide a helper which clearly documents the usage of driver_override. This will allow later to reuse the helper and reduce amount of duplicated code. Convert the platform driver to use new helper and make the driver_override field const char (it is not modified by the core). Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> --- drivers/base/driver.c | 51 +++++++++++++++++++++++++++++++++ drivers/base/platform.c | 28 +++--------------- include/linux/device/driver.h | 2 ++ include/linux/platform_device.h | 7 ++++- 4 files changed, 63 insertions(+), 25 deletions(-)