| Message ID | 20241001-cleanup-if_not_cond_guard-v1-1-7753810b0f7a@baylibre.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | cleanup: add if_not_cond_guard macro | expand |
[ add Fabio ] David Lechner wrote: > Add a new if_not_cond_guard() macro to cleanup.h for handling > conditional guards such as mutext_trylock(). > > This is more ergonomic than scoped_cond_guard() for most use cases. > Instead of hiding the error handling statement in the macro args, it > works like a normal if statement and allow the error path to be indented > while the normal code flow path is not indented. And it avoid unwanted > side-effect from hidden for loop in scoped_cond_guard(). > > Signed-off-by: David Lechner <dlechner@baylibre.com> Hi David, When you update this to the if_not_guard() name can you also add Fabio as a co-developer? His work [1] contributed to eliciting the response from Linus, and then this patch takes the novel additional step to create an "if ()" macro. Thanks for pushing this forward! [1]: http://lore.kernel.org/20240130164059.25130-1-fabio.maria.de.francesco@linux.intel.com
On 10/4/24 12:34 PM, Dan Williams wrote: > [ add Fabio ] > > David Lechner wrote: >> Add a new if_not_cond_guard() macro to cleanup.h for handling >> conditional guards such as mutext_trylock(). >> >> This is more ergonomic than scoped_cond_guard() for most use cases. >> Instead of hiding the error handling statement in the macro args, it >> works like a normal if statement and allow the error path to be indented >> while the normal code flow path is not indented. And it avoid unwanted >> side-effect from hidden for loop in scoped_cond_guard(). >> >> Signed-off-by: David Lechner <dlechner@baylibre.com> > > Hi David, > > When you update this to the if_not_guard() name can you also add Fabio as a > co-developer? His work [1] contributed to eliciting the response from Linus, > and then this patch takes the novel additional step to create an "if ()" macro. > > Thanks for pushing this forward! > > [1]: http://lore.kernel.org/20240130164059.25130-1-fabio.maria.de.francesco@linux.intel.com Sure, I didn't dig deep enough to find that patch, but basically the same idea. :-)
diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h index 038b2d523bf8..682bb3fadfc9 100644 --- a/include/linux/cleanup.h +++ b/include/linux/cleanup.h @@ -273,6 +273,10 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ * an anonymous instance of the (guard) class, not recommended for * conditional locks. * + * if_not_cond_guard(name, args...) { <error handling> }: + * convenience macro for conditional guards that calls the statement that + * follows only if the lock was not acquired (typically an error return). + * * 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 @@ -304,6 +308,13 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \ #define __guard_ptr(_name) class_##_name##_lock_ptr +#define __if_not_cond_guard(_name, _id, args...) \ + CLASS(_name, _id)(args); \ + if (!__guard_ptr(_name)(&_id)) + +#define if_not_cond_guard(_name, args...) \ + __if_not_cond_guard(_name, __UNIQUE_ID(guard), args) + #define scoped_guard(_name, args...) \ for (CLASS(_name, scope)(args), \ *done = NULL; __guard_ptr(_name)(&scope) && !done; done = (void *)1)
Add a new if_not_cond_guard() macro to cleanup.h for handling conditional guards such as mutext_trylock(). This is more ergonomic than scoped_cond_guard() for most use cases. Instead of hiding the error handling statement in the macro args, it works like a normal if statement and allow the error path to be indented while the normal code flow path is not indented. And it avoid unwanted side-effect from hidden for loop in scoped_cond_guard(). Signed-off-by: David Lechner <dlechner@baylibre.com> --- include/linux/cleanup.h | 11 +++++++++++ 1 file changed, 11 insertions(+)