| Message ID | 20191021143742.14487-2-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Johannes Berg |
| Headers | show |
| Series | debugfs: Add and use debugfs_create_xul() | expand |
On Mon, Oct 21, 2019 at 04:37:36PM +0200, Geert Uytterhoeven wrote: > The existing debugfs_create_ulong() function supports objects of > type "unsigned long", which are 32-bit or 64-bit depending on the > platform, in decimal form. To format objects in hexadecimal, various > debugfs_create_x*() functions exist, but all of them take fixed-size > types. > > Add a debugfs helper for "unsigned long" objects in hexadecimal format. > This avoids the need for users to open-code the same, or introduce > bugs when casting the value pointer to "u32 *" or "u64 *" to call > debugfs_create_x{32,64}(). > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > include/linux/debugfs.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h > index 33690949b45d6904..d7b2aebcc277d65e 100644 > --- a/include/linux/debugfs.h > +++ b/include/linux/debugfs.h > @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, > > #endif > > +static inline void debugfs_create_xul(const char *name, umode_t mode, > + struct dentry *parent, > + unsigned long *value) > +{ > + if (sizeof(*value) == sizeof(u32)) > + debugfs_create_x32(name, mode, parent, (u32 *)value); > + else > + debugfs_create_x64(name, mode, parent, (u64 *)value); > +} Looks sane, but can you add some kernel-doc comments here so that we can pull it into the debugfs documentation? Also there is debugfs documentation in Documentation/filesystems/ so maybe also add this there? I am going to be overhauling the debugfs documentation "soon" but it's at the lower part of my todo list, so it will take a while, might as well keep it up to date with new stuff added like this so that people don't get lost. thanks, greg k-h
Hi Greg, On Mon, Oct 21, 2019 at 4:45 PM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Mon, Oct 21, 2019 at 04:37:36PM +0200, Geert Uytterhoeven wrote: > > The existing debugfs_create_ulong() function supports objects of > > type "unsigned long", which are 32-bit or 64-bit depending on the > > platform, in decimal form. To format objects in hexadecimal, various > > debugfs_create_x*() functions exist, but all of them take fixed-size > > types. > > > > Add a debugfs helper for "unsigned long" objects in hexadecimal format. > > This avoids the need for users to open-code the same, or introduce > > bugs when casting the value pointer to "u32 *" or "u64 *" to call > > debugfs_create_x{32,64}(). > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > > --- > > include/linux/debugfs.h | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h > > index 33690949b45d6904..d7b2aebcc277d65e 100644 > > --- a/include/linux/debugfs.h > > +++ b/include/linux/debugfs.h > > @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, > > > > #endif > > > > +static inline void debugfs_create_xul(const char *name, umode_t mode, > > + struct dentry *parent, > > + unsigned long *value) > > +{ > > + if (sizeof(*value) == sizeof(u32)) > > + debugfs_create_x32(name, mode, parent, (u32 *)value); > > + else > > + debugfs_create_x64(name, mode, parent, (u64 *)value); > > +} > > Looks sane, but can you add some kernel-doc comments here so that we can > pull it into the debugfs documentation? Also there is debugfs Sure, will do. > documentation in Documentation/filesystems/ so maybe also add this > there? I am going to be overhauling the debugfs documentation "soon" > but it's at the lower part of my todo list, so it will take a while, > might as well keep it up to date with new stuff added like this so that > people don't get lost. Right. Currently it already lacks debugfs_create_ulong(). Will add both debugfs_create_ulong() and debugfs_create_xul(). Gr{oetje,eeting}s, Geert
On Mon, 2019-10-21 at 16:37 +0200, Geert Uytterhoeven wrote: > The existing debugfs_create_ulong() function supports objects of > type "unsigned long", which are 32-bit or 64-bit depending on the > platform, in decimal form. To format objects in hexadecimal, various > debugfs_create_x*() functions exist, but all of them take fixed-size > types. > > Add a debugfs helper for "unsigned long" objects in hexadecimal format. > This avoids the need for users to open-code the same, or introduce > bugs when casting the value pointer to "u32 *" or "u64 *" to call > debugfs_create_x{32,64}(). [] > diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h [] > @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, > > #endif > > +static inline void debugfs_create_xul(const char *name, umode_t mode, > + struct dentry *parent, > + unsigned long *value) > +{ > + if (sizeof(*value) == sizeof(u32)) > + debugfs_create_x32(name, mode, parent, (u32 *)value); > + else > + debugfs_create_x64(name, mode, parent, (u64 *)value); trivia: the casts are unnecessary. This might be more sensible using #ifdef static inline void debugfs_create_xul(const char *name, umode_t mode, struct dentry *parent, unsigned long *value) { #if BITS_PER_LONG == 64 debugfs_create_x64(name, mode, parent, value); #else debugfs_create_x32(name, mode, parent, value); #endif }
Hi Joe, On Mon, Oct 21, 2019 at 5:37 PM Joe Perches <joe@perches.com> wrote: > On Mon, 2019-10-21 at 16:37 +0200, Geert Uytterhoeven wrote: > > The existing debugfs_create_ulong() function supports objects of > > type "unsigned long", which are 32-bit or 64-bit depending on the > > platform, in decimal form. To format objects in hexadecimal, various > > debugfs_create_x*() functions exist, but all of them take fixed-size > > types. > > > > Add a debugfs helper for "unsigned long" objects in hexadecimal format. > > This avoids the need for users to open-code the same, or introduce > > bugs when casting the value pointer to "u32 *" or "u64 *" to call > > debugfs_create_x{32,64}(). > [] > > diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h > [] > > @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, > > > > #endif > > > > +static inline void debugfs_create_xul(const char *name, umode_t mode, > > + struct dentry *parent, > > + unsigned long *value) > > +{ > > + if (sizeof(*value) == sizeof(u32)) > > + debugfs_create_x32(name, mode, parent, (u32 *)value); > > + else > > + debugfs_create_x64(name, mode, parent, (u64 *)value); > > trivia: the casts are unnecessary. They are necessary, in both calls (so using #ifdef as suggested below won't help): include/linux/debugfs.h:375:42: error: passing argument 4 of ‘debugfs_create_x32’ from incompatible pointer type [-Werror=incompatible-pointer-types] debugfs_create_x32(name, mode, parent, value); ^~~~~ include/linux/debugfs.h:114:6: note: expected ‘u32 * {aka unsigned int *}’ but argument is of type ‘long unsigned int *’ void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent, ^~~~~~~~~~~~~~~~~~ include/linux/debugfs.h:377:42: error: passing argument 4 of ‘debugfs_create_x64’ from incompatible pointer type [-Werror=incompatible-pointer-types] debugfs_create_x64(name, mode, parent, value); ^~~~~ include/linux/debugfs.h:116:6: note: expected ‘u64 * {aka long long unsigned int *}’ but argument is of type ‘long unsigned int *’ void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent, ^~~~~~~~~~~~~~~~~~ > This might be more sensible using #ifdef > > static inline void debugfs_create_xul(const char *name, umode_t mode, > struct dentry *parent, > unsigned long *value) > { > #if BITS_PER_LONG == 64 > debugfs_create_x64(name, mode, parent, value); > #else > debugfs_create_x32(name, mode, parent, value); > #endif > } ... at the expense of the compiler checking only one branch. Just like "if (IS_ENABLED(CONFIG_<foo>)" (when possible) is preferred over "#ifdef CONFIG_<foo>" because of compile-coverage, I think using "if" here is better than using "#if". Gr{oetje,eeting}s, Geert
On Tue, 2019-10-22 at 10:03 +0200, Geert Uytterhoeven wrote: > Hi Joe, Hey again Geert. > On Mon, Oct 21, 2019 at 5:37 PM Joe Perches <joe@perches.com> wrote: > > On Mon, 2019-10-21 at 16:37 +0200, Geert Uytterhoeven wrote: > > > The existing debugfs_create_ulong() function supports objects of > > > type "unsigned long", which are 32-bit or 64-bit depending on the > > > platform, in decimal form. To format objects in hexadecimal, various > > > debugfs_create_x*() functions exist, but all of them take fixed-size > > > types. > > > > > > Add a debugfs helper for "unsigned long" objects in hexadecimal format. > > > This avoids the need for users to open-code the same, or introduce > > > bugs when casting the value pointer to "u32 *" or "u64 *" to call > > > debugfs_create_x{32,64}(). > > [] > > > diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h > > [] > > > @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, > > > > > > #endif > > > > > > +static inline void debugfs_create_xul(const char *name, umode_t mode, > > > + struct dentry *parent, > > > + unsigned long *value) > > > +{ > > > + if (sizeof(*value) == sizeof(u32)) > > > + debugfs_create_x32(name, mode, parent, (u32 *)value); > > > + else > > > + debugfs_create_x64(name, mode, parent, (u64 *)value); > > > > trivia: the casts are unnecessary. > > They are necessary, in both calls (so using #ifdef as suggested below > won't help): Silly thinko, (I somehow thought the compiler would eliminate the code after the branch not taken, but of course it has to compile it first... oops) though the #ifdef should work. > > This might be more sensible using #ifdef > > > > static inline void debugfs_create_xul(const char *name, umode_t mode, > > struct dentry *parent, > > unsigned long *value) > > { > > #if BITS_PER_LONG == 64 > > debugfs_create_x64(name, mode, parent, value); > > #else > > debugfs_create_x32(name, mode, parent, value); > > #endif > > } > > ... at the expense of the compiler checking only one branch. > > Just like "if (IS_ENABLED(CONFIG_<foo>)" (when possible) is preferred > over "#ifdef CONFIG_<foo>" because of compile-coverage, I think using > "if" here is better than using "#if". True if all compilers will always eliminate the unused branch.
On Tue, Oct 22, 2019 at 02:07:34AM -0700, Joe Perches wrote: > On Tue, 2019-10-22 at 10:03 +0200, Geert Uytterhoeven wrote: > > Hi Joe, > > Hey again Geert. > > > On Mon, Oct 21, 2019 at 5:37 PM Joe Perches <joe@perches.com> wrote: > > > On Mon, 2019-10-21 at 16:37 +0200, Geert Uytterhoeven wrote: > > > > The existing debugfs_create_ulong() function supports objects of > > > > type "unsigned long", which are 32-bit or 64-bit depending on the > > > > platform, in decimal form. To format objects in hexadecimal, various > > > > debugfs_create_x*() functions exist, but all of them take fixed-size > > > > types. > > > > > > > > Add a debugfs helper for "unsigned long" objects in hexadecimal format. > > > > This avoids the need for users to open-code the same, or introduce > > > > bugs when casting the value pointer to "u32 *" or "u64 *" to call > > > > debugfs_create_x{32,64}(). > > > [] > > > > diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h > > > [] > > > > @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, > > > > > > > > #endif > > > > > > > > +static inline void debugfs_create_xul(const char *name, umode_t mode, > > > > + struct dentry *parent, > > > > + unsigned long *value) > > > > +{ > > > > + if (sizeof(*value) == sizeof(u32)) > > > > + debugfs_create_x32(name, mode, parent, (u32 *)value); > > > > + else > > > > + debugfs_create_x64(name, mode, parent, (u64 *)value); > > > > > > trivia: the casts are unnecessary. > > > > They are necessary, in both calls (so using #ifdef as suggested below > > won't help): > > Silly thinko, (I somehow thought the compiler would > eliminate the code after the branch not taken, but > of course it has to compile it first... oops) > though the #ifdef should work. > > > > This might be more sensible using #ifdef > > > > > > static inline void debugfs_create_xul(const char *name, umode_t mode, > > > struct dentry *parent, > > > unsigned long *value) > > > { > > > #if BITS_PER_LONG == 64 > > > debugfs_create_x64(name, mode, parent, value); > > > #else > > > debugfs_create_x32(name, mode, parent, value); > > > #endif > > > } > > > > ... at the expense of the compiler checking only one branch. > > > > Just like "if (IS_ENABLED(CONFIG_<foo>)" (when possible) is preferred > > over "#ifdef CONFIG_<foo>" because of compile-coverage, I think using > > "if" here is better than using "#if". > > True if all compilers will always eliminate the unused branch. Good ones will, we don't care about bad ones :)
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index 33690949b45d6904..d7b2aebcc277d65e 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, #endif +static inline void debugfs_create_xul(const char *name, umode_t mode, + struct dentry *parent, + unsigned long *value) +{ + if (sizeof(*value) == sizeof(u32)) + debugfs_create_x32(name, mode, parent, (u32 *)value); + else + debugfs_create_x64(name, mode, parent, (u64 *)value); +} + #endif
The existing debugfs_create_ulong() function supports objects of type "unsigned long", which are 32-bit or 64-bit depending on the platform, in decimal form. To format objects in hexadecimal, various debugfs_create_x*() functions exist, but all of them take fixed-size types. Add a debugfs helper for "unsigned long" objects in hexadecimal format. This avoids the need for users to open-code the same, or introduce bugs when casting the value pointer to "u32 *" or "u64 *" to call debugfs_create_x{32,64}(). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- include/linux/debugfs.h | 10 ++++++++++ 1 file changed, 10 insertions(+)