Re: [PATCH v3 1/1] eventfd: implementation of EFD_MASK flag
From: Damian Hobson-Garcia <hidden>
Date: 2015-10-22 07:47:03
Also in:
linux-api, linux-fsdevel, lkml
Hello,
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diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index ff0b981..87de343 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h
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-/* - * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining - * new flags, since they might collide with O_* ones. We want - * to re-use O_* flags that couldn't possibly have a meaning - * from eventfd, in order to leave a free define-space for - * shared O_* flags. - */ -#define EFD_SEMAPHORE (1 << 0) -#define EFD_CLOEXEC O_CLOEXEC -#define EFD_NONBLOCK O_NONBLOCK - -#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) -#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE) - struct file; #ifdef CONFIG_EVENTFDdiff --git a/include/uapi/linux/eventfd.h b/include/uapi/linux/eventfd.h new file mode 100644 index 0000000..097dcad --- /dev/null +++ b/include/uapi/linux/eventfd.h@@ -0,0 +1,33 @@
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+ +/* + * CAREFUL: Check include/asm-generic/fcntl.h when defining + * new flags, since they might collide with O_* ones. We want + * to re-use O_* flags that couldn't possibly have a meaning + * from eventfd, in order to leave a free define-space for + * shared O_* flags. + */ + +/* Provide semaphore-like semantics for reads from the eventfd. */ +#define EFD_SEMAPHORE (1 << 0) +/* Provide event mask semantics for the eventfd. */ +#define EFD_MASK (1 << 1) +/* Set the close-on-exec (FD_CLOEXEC) flag on the eventfd. */ +#define EFD_CLOEXEC O_CLOEXEC +/* Create the eventfd in non-blocking mode. */ +#define EFD_NONBLOCK O_NONBLOCK +#endif /* _UAPI_LINUX_EVENTFD_H */
Since the latest version of this patch adds only the EFD_MASK definition to the eventfd header, I was wondering if it was really necessary/recommended to move the definitions from linux/eventfd.h to linux/uapi/eventfd.h. From my understanding, the EFD_SEMAPHORE (and now EFD_MASK) define(s) are provided to user space from the libc headers only. Any advice would be greatly appreciated. Thank you, Damian