From d362af89d8019ff12d3550c83de2c3aa5d9f095b Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Mon, 18 Apr 2022 09:50:04 +0000 Subject: syscall: golf + more idiomatic buffer initialization While `vec' is useful for user-supplied buffers to avoid excess memory traffic, but provides no benefit when we need to allocate our own buffers as we do in nodatacow_fh, since Perl can't elide memset(ptr, 0, len). So just use the idiomatic `"\0" x $LEN' here. --- lib/PublicInbox/Syscall.pm | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'lib/PublicInbox/Syscall.pm') diff --git a/lib/PublicInbox/Syscall.pm b/lib/PublicInbox/Syscall.pm index cc282f9f..22b779ad 100644 --- a/lib/PublicInbox/Syscall.pm +++ b/lib/PublicInbox/Syscall.pm @@ -390,12 +390,10 @@ sub rename_noreplace ($$) { } } -sub nodatacow_fh { - return if !defined($SYS_fstatfs); - my $buf = ''; - vec($buf, 120 * 8 - 1, 1) = 0; +sub nodatacow_fh ($) { my ($fh) = @_; - syscall($SYS_fstatfs, fileno($fh), $buf) == 0 or + my $buf = "\0" x 120; + syscall($SYS_fstatfs // return, fileno($fh), $buf) == 0 or return warn("fstatfs: $!\n"); my $f_type = unpack('l!', $buf); # statfs.f_type is a signed word return if $f_type != 0x9123683E; # BTRFS_SUPER_MAGIC -- cgit v1.2.3-24-ge0c7