From b92bea5d2a9481de69bb627a7b442a9f58fca43d Mon Sep 17 00:00:00 2001 From: Zbigniew Jędrzejewski-Szmek Date: Sun, 24 Mar 2013 19:59:00 -0400 Subject: Use initalization instead of explicit zeroing MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Before, we would initialize many fields twice: first by filling the structure with zeros, and then a second time with the real values. We can let the compiler do the job for us, avoiding one copy. A downside of this patch is that text gets slightly bigger. This is because all zero() calls are effectively inlined: $ size build/.libs/systemd text data bss dec hex filename before 897737 107300 2560 1007597 f5fed build/.libs/systemd after 897873 107300 2560 1007733 f6075 build/.libs/systemd … actually less than 1‰. A few asserts that the parameter is not null had to be removed. I don't think this changes much, because first, it is quite unlikely for the assert to fail, and second, an immediate SEGV is almost as good as an assert. --- src/readahead/readahead-collect.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) (limited to 'src/readahead') diff --git a/src/readahead/readahead-collect.c b/src/readahead/readahead-collect.c index b2d0f68726..03583928a0 100644 --- a/src/readahead/readahead-collect.c +++ b/src/readahead/readahead-collect.c @@ -75,10 +75,7 @@ static usec_t starttime; #define PTR_TO_SECTOR(p) (PTR_TO_ULONG(p)-1) static int btrfs_defrag(int fd) { - struct btrfs_ioctl_vol_args data; - - zero(data); - data.fd = fd; + struct btrfs_ioctl_vol_args data = { .fd = fd }; return ioctl(fd, BTRFS_IOC_DEFRAG, &data); } @@ -186,11 +183,10 @@ static unsigned long fd_first_block(int fd) { struct { struct fiemap fiemap; struct fiemap_extent extent; - } data; - - zero(data); - data.fiemap.fm_length = ~0ULL; - data.fiemap.fm_extent_count = 1; + } data = { + .fiemap.fm_length = ~0ULL, + .fiemap.fm_extent_count = 1, + }; if (ioctl(fd, FS_IOC_FIEMAP, &data) < 0) return 0; @@ -238,7 +234,7 @@ static int collect(const char *root) { FD_INOTIFY, /* We get notifications to quit early via this fd */ _FD_MAX }; - struct pollfd pollfd[_FD_MAX]; + struct pollfd pollfd[_FD_MAX] = {}; int fanotify_fd = -1, signal_fd = -1, inotify_fd = -1, r = 0; pid_t my_pid; Hashmap *files = NULL; @@ -314,7 +310,6 @@ static int collect(const char *root) { my_pid = getpid(); - zero(pollfd); pollfd[FD_FANOTIFY].fd = fanotify_fd; pollfd[FD_FANOTIFY].events = POLLIN; pollfd[FD_SIGNAL].fd = signal_fd; -- cgit v1.2.3-54-g00ecf