Changes from v1 (https://lkml.org/lkml/2015/1/20/189): - As discussed in previous thread [1], split the call to epoll_ctl_batch and epoll_pwait. [Michael] - Fix memory leaks. [Omar] - Add a short comment about the ignored copy_to_user failure. [Omar] - Cover letter rewritten. This adds two new system calls as described below. I mentioned glibc wrapping of sigarg in epoll_pwait1 description, so don't read it as end user man page yet. One caveat is the possible failure of the last copy_to_user in epoll_ctl_batch, which returns per command error code. Ideas to improve that are welcome! 1) epoll_ctl_batch ------------------ NAME epoll_ctl_batch - modify an epoll descriptor in batch SYNOPSIS #include <sys/epoll.h> int epoll_ctl_batch(int epfd, int flags, int ncmds, struct epoll_ctl_cmd *cmds); DESCRIPTION The system call performs a batch of epoll_ctl operations. It allows efficient update of events on this epoll descriptor. Flags is reserved and must be 0. Each operation is specified as an element in the cmds array, defined as: struct epoll_ctl_cmd { /* Reserved flags for future extension, must be 0. */ int flags; /* The same as epoll_ctl() op parameter. */ int op; /* The same as epoll_ctl() fd parameter. */ int fd; /* The same as the "events" field in struct epoll_event. */ uint32_t events; /* The same as the "data" field in struct epoll_event. */ uint64_t data; /* Output field, will be set to the return code after this * command is executed by kernel */ int error_hint; }; Commands are executed in their order in cmds, and if one of them failed, the rest after it are not tried. Not that this call isn't atomic in terms of updating the epoll descriptor, which means a second epoll_ctl or epoll_ctl_batch call during the first epoll_ctl_batch may make the operation sequence interleaved. However, each single epoll_ctl_cmd operation has the same semantics as a epoll_ctl call. RETURN VALUE If one or more of the parameters are incorrect, -1 is returned and errno is set appropriately. Otherwise, the number of succeeded commands is returned. Each error_hint field may be set to the error code or 0, depending on the result of the command. If there is some error in returning the error to user, it may also be unchanged, even though the command may actually be executed. In this case, it's still ensured that the i-th (i = ret) command is the failed command. ERRORS Errors for the overall system call (in errno) are: EINVAL flags is non-zero, or ncmds is less than or equal to zero, or cmds is NULL. ENOMEM There was insufficient memory to handle the requested op control operation. EFAULT The memory area pointed to by cmds is not accessible with write permissions. Errors for each command (in error_hint) are: EBADF epfd or fd is not a valid file descriptor. EEXIST op was EPOLL_CTL_ADD, and the supplied file descriptor fd is already registered with this epoll instance. EINVAL epfd is not an epoll file descriptor, or fd is the same as epfd, or the requested operation op is not supported by this interface. ENOENT op was EPOLL_CTL_MOD or EPOLL_CTL_DEL, and fd is not registered with this epoll instance. ENOMEM There was insufficient memory to handle the requested op control operation. ENOSPC The limit imposed by /proc/sys/fs/epoll/max_user_watches was encountered while trying to register (EPOLL_CTL_ADD) a new file descriptor on an epoll instance. See epoll(7) for further details. EPERM The target file fd does not support epoll. CONFORMING TO epoll_ctl_batch() is Linux-specific. SEE ALSO epoll_create(2), epoll_ctl(2), epoll_wait(2), epoll_pwait(2), epoll(7) 2) epoll_pwait1 --------------- NAME epoll_pwait1 - wait for an I/O event on an epoll file descriptor SYNOPSIS #include <sys/epoll.h> int epoll_pwait1(int epfd, int flags, struct epoll_event *events, int maxevents, struct timespec *timeout, struct sigargs *sig); DESCRIPTION The epoll_pwait1 system call differs from epoll_pwait only in parameter types. The first difference is timeout, a pointer to timespec structure which allows nanosecond presicion; the second difference, which should probably be wrapper by glibc and only expose a sigset_t pointer as in pselect6. If timeout is NULL, it's treated as if 0 is specified in epoll_pwait (return immediately). Otherwise it's converted to nanosecond scalar, again, with the same convention as epoll_pwait's timeout. RETURN VALUE The same as said in epoll_pwait(2). ERRORS The same as said in man epoll_pwait(2), plus: EINVAL flags is not zero. CONFORMING TO epoll_pwait1() is Linux-specific. SEE ALSO epoll_create(2), epoll_ctl(2), epoll_wait(2), epoll_pwait(2), epoll(7) Fam Zheng (7): epoll: Extract epoll_wait_do and epoll_pwait_do epoll: Specify clockid explicitly epoll: Extract ep_ctl_do epoll: Add implementation for epoll_ctl_batch x86: Hook up epoll_ctl_batch syscall epoll: Add implementation for epoll_pwait1 x86: Hook up epoll_pwait1 syscall arch/x86/syscalls/syscall_32.tbl | 2 + arch/x86/syscalls/syscall_64.tbl | 2 + fs/eventpoll.c | 241 ++++++++++++++++++++++++++------------- include/linux/syscalls.h | 9 ++ include/uapi/linux/eventpoll.h | 11 ++ 5 files changed, 186 insertions(+), 79 deletions(-) -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
