| Message ID | 20240204173105.935612-2-fabio.maria.de.francesco@linux.intel.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add cond_guard() to conditional guards | expand |
On Sun, 4 Feb 2024 18:31:04 +0100 "Fabio M. De Francesco" <fabio.maria.de.francesco@linux.intel.com> wrote: > Add cond_guard() macro to conditional guards. > > cond_guard() is a guard to be used with the conditional variants of locks, > like down_read_trylock() or mutex_lock_interruptible(). > > It takes a statement (or more statements in a block) that is passed to its > second argument. That statement (or block) is executed if waiting for a > lock is interrupted or if a _trylock() fails in case of contention. > > Usage example: > > cond_guard(rwsem_read_try, { printk(...); return 0; }, &semaphore); > > Consistenly with the other guards, locks are unlocked at the exit of the Spell check. > scope where cond_guard() is called. > > Cc: Peter Zijlstra <peterz@infradead.org> > Suggested-by: Dan Williams <dan.j.williams@intel.com> > Suggested-by: Ira Weiny <ira.weiny@intel.com> > Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com> > --- > include/linux/cleanup.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h > index c2d09bc4f976..3826e8ed4e09 100644 > --- a/include/linux/cleanup.h > +++ b/include/linux/cleanup.h > @@ -134,6 +134,16 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ > * an anonymous instance of the (guard) class, not recommended for > * conditional locks. > * > + * cond_guard(name, fail, args...): > + * a guard to be used with the conditional variants of locks, like > + * down_read_trylock() or mutex_lock_interruptible. 'fail' are one or more > + * statements that are executed if waiting for a lock is interrupted or > + * if a _trylock() fails in case of contention. > + * > + * Example: > + * > + * cond_guard(rwsem_read_try, { printk(...); return 0; }, &semaphore); > + * > * scoped_guard (name, args...) { }: > * similar to CLASS(name, scope)(args), except the variable (with the > * explicit name 'scope') is declard in a for-loop such that its scope is > @@ -165,6 +175,10 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ > > #define __guard_ptr(_name) class_##_name##_lock_ptr > > +#define cond_guard(_name, _ret, args...) \ > + CLASS(_name, scope)(args); \ > + if (!__guard_ptr(_name)(&scope)) _ret Use the naming that scoped_cond_guard() uses: _fail rather than _ret > + > #define scoped_guard(_name, args...) \ > for (CLASS(_name, scope)(args), \ > *done = NULL; __guard_ptr(_name)(&scope) && !done; done = (void *)1)
Fabio M. De Francesco wrote: > Add cond_guard() macro to conditional guards. > > cond_guard() is a guard to be used with the conditional variants of locks, > like down_read_trylock() or mutex_lock_interruptible(). > > It takes a statement (or more statements in a block) that is passed to its > second argument. That statement (or block) is executed if waiting for a > lock is interrupted or if a _trylock() fails in case of contention. > > Usage example: > > cond_guard(rwsem_read_try, { printk(...); return 0; }, &semaphore); > > Consistenly with the other guards, locks are unlocked at the exit of the Consistently Reviewed-by: Ira Weiny <ira.weiny@intel.com> > scope where cond_guard() is called. > > Cc: Peter Zijlstra <peterz@infradead.org> > Suggested-by: Dan Williams <dan.j.williams@intel.com> > Suggested-by: Ira Weiny <ira.weiny@intel.com> > Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com> > --- > include/linux/cleanup.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h > index c2d09bc4f976..3826e8ed4e09 100644 > --- a/include/linux/cleanup.h > +++ b/include/linux/cleanup.h > @@ -134,6 +134,16 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ > * an anonymous instance of the (guard) class, not recommended for > * conditional locks. > * > + * cond_guard(name, fail, args...): > + * a guard to be used with the conditional variants of locks, like > + * down_read_trylock() or mutex_lock_interruptible. 'fail' are one or more > + * statements that are executed if waiting for a lock is interrupted or > + * if a _trylock() fails in case of contention. > + * > + * Example: > + * > + * cond_guard(rwsem_read_try, { printk(...); return 0; }, &semaphore); > + * > * scoped_guard (name, args...) { }: > * similar to CLASS(name, scope)(args), except the variable (with the > * explicit name 'scope') is declard in a for-loop such that its scope is > @@ -165,6 +175,10 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ > > #define __guard_ptr(_name) class_##_name##_lock_ptr > > +#define cond_guard(_name, _ret, args...) \ > + CLASS(_name, scope)(args); \ > + if (!__guard_ptr(_name)(&scope)) _ret > + > #define scoped_guard(_name, args...) \ > for (CLASS(_name, scope)(args), \ > *done = NULL; __guard_ptr(_name)(&scope) && !done; done = (void *)1) > -- > 2.43.0 >
Fabio M. De Francesco wrote: > Add cond_guard() macro to conditional guards. > > cond_guard() is a guard to be used with the conditional variants of locks, > like down_read_trylock() or mutex_lock_interruptible(). > > It takes a statement (or more statements in a block) that is passed to its s/or more statements in a block/or statement-expression)/ s/to its/as its/ > second argument. That statement (or block) is executed if waiting for a > lock is interrupted or if a _trylock() fails in case of contention. > > Usage example: > > cond_guard(rwsem_read_try, { printk(...); return 0; }, &semaphore); Missed commenting on this in the last posting, but multi-statement fail cases that print and return 0 are unlikely to ever be the common case. I think the most simple to understand example is an interruptible lock that returns -EINTR on failure: cond_guard(mutex_intr, return -EINTR, &mutex); ...and then maybe mention that _fail can be a statement-expression if needed. > Consistenly with the other guards, locks are unlocked at the exit of the s/Consistenly with the other guards/Consistent with other usage of guard()/
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index c2d09bc4f976..3826e8ed4e09 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -134,6 +134,16 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ * an anonymous instance of the (guard) class, not recommended for * conditional locks. * + * cond_guard(name, fail, args...): + * a guard to be used with the conditional variants of locks, like + * down_read_trylock() or mutex_lock_interruptible. 'fail' are one or more + * statements that are executed if waiting for a lock is interrupted or + * if a _trylock() fails in case of contention. + * + * Example: + * + * cond_guard(rwsem_read_try, { printk(...); return 0; }, &semaphore); + * * scoped_guard (name, args...) { }: * similar to CLASS(name, scope)(args), except the variable (with the * explicit name 'scope') is declard in a for-loop such that its scope is @@ -165,6 +175,10 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ #define __guard_ptr(_name) class_##_name##_lock_ptr +#define cond_guard(_name, _ret, args...) \ + CLASS(_name, scope)(args); \ + if (!__guard_ptr(_name)(&scope)) _ret + #define scoped_guard(_name, args...) \ for (CLASS(_name, scope)(args), \ *done = NULL; __guard_ptr(_name)(&scope) && !done; done = (void *)1)
Add cond_guard() macro to conditional guards. cond_guard() is a guard to be used with the conditional variants of locks, like down_read_trylock() or mutex_lock_interruptible(). It takes a statement (or more statements in a block) that is passed to its second argument. That statement (or block) is executed if waiting for a lock is interrupted or if a _trylock() fails in case of contention. Usage example: cond_guard(rwsem_read_try, { printk(...); return 0; }, &semaphore); Consistenly with the other guards, locks are unlocked at the exit of the scope where cond_guard() is called. Cc: Peter Zijlstra <peterz@infradead.org> Suggested-by: Dan Williams <dan.j.williams@intel.com> Suggested-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com> --- include/linux/cleanup.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+)