[PATCH 1/3] initramfs: move unnecessary memcmp from hot path
From: David Disseldorp <hidden>
Date: 2021-06-10 21:46:03
Also in:
linux-fsdevel
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
do_header() is called for each cpio entry and first checks for "newc" magic before parsing further. The magic check includes a special case error message if POSIX.1 ASCII (cpio -H odc) magic is detected. This special case POSIX.1 check needn't be done in the hot path, so move it under the non-newc-magic error path. Signed-off-by: David Disseldorp <redacted> --- init/initramfs.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/init/initramfs.c b/init/initramfs.c
index af27abc59643..f01590cefa2d 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c@@ -256,12 +256,11 @@ static int __init do_collect(void) static int __init do_header(void) { - if (memcmp(collected, "070707", 6)==0) { - error("incorrect cpio method used: use -H newc option"); - return 1; - } if (memcmp(collected, "070701", 6)) { - error("no cpio magic"); + if (memcmp(collected, "070707", 6) == 0) + error("incorrect cpio method used: use -H newc option"); + else + error("no cpio magic"); return 1; } parse_header(collected);
--
2.26.2