Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Fri, 31 Mar 2023 16:49:49 +0200 | Subject | Re: [PATCH 4/7] driver core: clean up the logic to determine which /sys/dev/ directory to use |
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On Fri, Mar 31, 2023 at 11:33 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > When a dev_t is set in a struct device, an symlink in /sys/dev/ is > created for it either under /sys/dev/block/ or /sys/dev/char/ depending > on the device type. > > The logic to determine this would trigger off of the class of the > object, and the kobj_type set in that location. But it turns out that > this deep nesting isn't needed at all, as it's either a choice of block > or "everything else" which is a char device. So make the logic a lot > more simple and obvious, and remove the incorrect comments in the code > that tried to document something that was not happening at all (it is > impossible to set class->dev_kobj to NULL as the class core prevented > that from happening. > > This removes the only place that class->dev_kobj was being used, so > after this, it can be removed entirely. > > Cc: "Rafael J. Wysocki" <rafael@kernel.org> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I like this.
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
> --- > drivers/base/base.h | 10 ++++++++++ > drivers/base/core.c | 22 ++++------------------ > drivers/base/devtmpfs.c | 9 --------- > 3 files changed, 14 insertions(+), 27 deletions(-) > > diff --git a/drivers/base/base.h b/drivers/base/base.h > index 6296164bb7f3..4660e1159ee0 100644 > --- a/drivers/base/base.h > +++ b/drivers/base/base.h > @@ -209,6 +209,16 @@ int devtmpfs_init(void); > static inline int devtmpfs_init(void) { return 0; } > #endif > > +#ifdef CONFIG_BLOCK > +extern struct class block_class; > +static inline bool is_blockdev(struct device *dev) > +{ > + return dev->class == &block_class; > +} > +#else > +static inline bool is_blockdev(struct device *dev) { return false; } > +#endif > + > /* Device links support */ > int device_links_read_lock(void); > void device_links_read_unlock(int idx); > diff --git a/drivers/base/core.c b/drivers/base/core.c > index e3bc34fcf779..dbc2ba6dfffc 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -3430,27 +3430,13 @@ int dev_set_name(struct device *dev, const char *fmt, ...) > } > EXPORT_SYMBOL_GPL(dev_set_name); > > -/** > - * device_to_dev_kobj - select a /sys/dev/ directory for the device > - * @dev: device > - * > - * By default we select char/ for new entries. Setting class->dev_obj > - * to NULL prevents an entry from being created. class->dev_kobj must > - * be set (or cleared) before any devices are registered to the class > - * otherwise device_create_sys_dev_entry() and > - * device_remove_sys_dev_entry() will disagree about the presence of > - * the link. > - */ > +/* select a /sys/dev/ directory for the device */ > static struct kobject *device_to_dev_kobj(struct device *dev) > { > - struct kobject *kobj; > - > - if (dev->class) > - kobj = dev->class->dev_kobj; > + if (is_blockdev(dev)) > + return sysfs_dev_block_kobj; > else > - kobj = sysfs_dev_char_kobj; > - > - return kobj; > + return sysfs_dev_char_kobj; > } > > static int device_create_sys_dev_entry(struct device *dev) > diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c > index ae72d4ba8547..b848764ef018 100644 > --- a/drivers/base/devtmpfs.c > +++ b/drivers/base/devtmpfs.c > @@ -94,15 +94,6 @@ static struct file_system_type dev_fs_type = { > .mount = public_dev_mount, > }; > > -#ifdef CONFIG_BLOCK > -static inline int is_blockdev(struct device *dev) > -{ > - return dev->class == &block_class; > -} > -#else > -static inline int is_blockdev(struct device *dev) { return 0; } > -#endif > - > static int devtmpfs_submit_req(struct req *req, const char *tmp) > { > init_completion(&req->done); > -- > 2.40.0 >
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