From patchwork Tue May 9 14:49:18 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joseph Myers X-Patchwork-Id: 20323 Received: (qmail 107917 invoked by alias); 9 May 2017 14:49:31 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 104712 invoked by uid 89); 9 May 2017 14:49:26 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-24.4 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_PASS, URIBL_RED autolearn=ham version=3.3.2 spammy=Hx-languages-length:4365, 2371 X-HELO: relay1.mentorg.com Date: Tue, 9 May 2017 14:49:18 +0000 From: Joseph Myers To: Subject: Simplify recvmmsg code Message-ID: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 X-ClientProxiedBy: svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) To svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) Now we can assume a kernel with recvmmsg support, this patch simplifies the implementation to be similar to that for accept4: either using socketcall or the syscall according to whether the syscall is known to be available, without further fallback implementations. (In fact further simplification is possible, getting rid of the __ASSUME_*_SYSCALL_WITH_SOCKETCALL macros now that the minimum kernel is guaranteed support for all of accept4, recvmmsg, sendmmsg, whether through syscalls or through socketcall. I intend to do that for all of accept4 / recvmmsg / sendmmsg together - so making their implementations just like those for older socket functions - once the basic cleanup for 3.2 minimum kernel is done for sendmmsg as well as recvmmsg.) Tested for x86_64 and x86. 2017-05-09 Joseph Myers * sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_RECVMMSG_SYSCALL): Define unconditionally. (__ASSUME_RECVMMSG_SOCKETCALL): Remove macro. (__ASSUME_RECVMMSG): Likewise. * sysdeps/unix/sysv/linux/recvmmsg.c (recvmmsg): Define using recvmmsg syscall if it can be assumed to be present, socketcall otherwise, with no fallback for runtime failure. diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index 74ac627..a5c2263 100644 --- a/sysdeps/unix/sysv/linux/kernel-features.h +++ b/sysdeps/unix/sysv/linux/kernel-features.h @@ -90,13 +90,7 @@ /* Support for recvmmsg functionality was added in 2.6.33. The macros defined correspond to those for accept4. */ -#if __LINUX_KERNEL_VERSION >= 0x020621 -# ifdef __ASSUME_SOCKETCALL -# define __ASSUME_RECVMMSG_SOCKETCALL 1 -# endif -# define __ASSUME_RECVMMSG_SYSCALL 1 -# define __ASSUME_RECVMMSG 1 -#endif +#define __ASSUME_RECVMMSG_SYSCALL 1 /* statfs fills in f_flags since 2.6.36. */ #if __LINUX_KERNEL_VERSION >= 0x020624 diff --git a/sysdeps/unix/sysv/linux/recvmmsg.c b/sysdeps/unix/sysv/linux/recvmmsg.c index 28eb678..1a1e1c1 100644 --- a/sysdeps/unix/sysv/linux/recvmmsg.c +++ b/sysdeps/unix/sysv/linux/recvmmsg.c @@ -23,71 +23,18 @@ #include #include -/* Do not use the recvmmsg syscall on socketcall architectures unless - it was added at the same time as the socketcall support or can be - assumed to be present. */ -#if defined __ASSUME_SOCKETCALL \ - && !defined __ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL \ - && !defined __ASSUME_RECVMMSG_SYSCALL -# undef __NR_recvmmsg -#endif - -#ifdef __NR_recvmmsg -int -recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, - struct timespec *tmo) -{ - return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); -} -#elif defined __NR_socketcall -# include -# ifdef __ASSUME_RECVMMSG_SOCKETCALL int recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, struct timespec *tmo) { + /* Do not use the recvmmsg syscall on socketcall architectures unless + it was added at the same time as the socketcall support or can be + assumed to be present. */ +#if defined __ASSUME_SOCKETCALL \ + && !defined __ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL \ + && !defined __ASSUME_RECVMMSG_SYSCALL return SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); -} -# else -static int have_recvmmsg; - -int -recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags, - struct timespec *tmo) -{ - if (__glibc_likely (have_recvmmsg >= 0)) - { - int ret = SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, - tmo); - /* The kernel returns -EINVAL for unknown socket operations. - We need to convert that error to an ENOSYS error. */ - if (__builtin_expect (ret < 0, 0) - && have_recvmmsg == 0 - && errno == EINVAL) - { - /* Try another call, this time with an invalid file - descriptor and all other parameters cleared. This call - will not cause any harm and it will return - immediately. */ - ret = SOCKETCALL_CANCEL (invalid, -1); - if (errno == EINVAL) - { - have_recvmmsg = -1; - __set_errno (ENOSYS); - } - else - { - have_recvmmsg = 1; - __set_errno (EINVAL); - } - return -1; - } - return ret; - } - __set_errno (ENOSYS); - return -1; -} -# endif /* __ASSUME_RECVMMSG_SOCKETCALL */ #else -# include + return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo); #endif +}