mke2fs: clean up kernel version tests

Refactor the running kernel version checks to hide the details of
version code checking, etc.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index 0ed02a55dc317ecc77499ef5c7c0878eb5903eaf..5b5398ef17b7c2e6bd91105d25de74eec637db06 100644 (file)
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -27,6 +27,7 @@
 #include <time.h>
 #ifdef __linux__
 #include <sys/utsname.h>
+#include <linux/version.h>
 #endif
 #ifdef HAVE_GETOPT_H
 #include <getopt.h>
@@ -173,7 +174,29 @@ static int parse_version_number(const char *s)
        rev = strtol(cp, &endptr, 10);
        if (cp == endptr)
                return 0;
-       return ((((major * 256) + minor) * 256) + rev);
+       return KERNEL_VERSION(major, minor, rev);
+}
+
+static int is_before_linux_ver(unsigned int major, unsigned int minor)
+{
+       struct          utsname ut;
+       static int      linux_version_code = -1;
+
+       if (uname(&ut)) {
+               perror("uname");
+               exit(1);
+       }
+       if (linux_version_code < 0)
+               linux_version_code = parse_version_number(ut.release);
+       if (linux_version_code == 0)
+               return 0;
+
+       return linux_version_code < KERNEL_VERSION(major, minor, 0);
+}
+#else
+static int is_before_linux_ver(unsigned int major, unsigned int minor)
+{
+       return 0;
 }
 #endif
 
@@ -1385,9 +1408,6 @@ static void PRS(int argc, char *argv[])
         * Finally, we complain about fs_blocks_count > 2^32 on a non-64bit fs.
         */
        blk64_t         fs_blocks_count = 0;
-#ifdef __linux__
-       struct          utsname ut;
-#endif
        long            sysval;
        int             s_opt = -1, r_opt = -1;
        char            *fs_features = 0;
@@ -1453,15 +1473,8 @@ profile_error:
        memset(&fs_param, 0, sizeof(struct ext2_super_block));
        fs_param.s_rev_level = 1;  /* Create revision 1 filesystems now */
 
-#ifdef __linux__
-       if (uname(&ut)) {
-               perror("uname");
-               exit(1);
-       }
-       linux_version_code = parse_version_number(ut.release);
-       if (linux_version_code && linux_version_code < (2*65536 + 2*256))
+       if (is_before_linux_ver(2, 2))
                fs_param.s_rev_level = 0;
-#endif
 
        if (argc && *argv) {
                program_name = get_progname(*argv);
@@ -1869,8 +1882,7 @@ profile_error:
 
                if (use_bsize == -1) {
                        use_bsize = sys_page_size;
-                       if ((linux_version_code < (2*65536 + 6*256)) &&
-                           (use_bsize > 4096))
+                       if (is_before_linux_ver(2, 6) && use_bsize > 4096)
                                use_bsize = 4096;
                }
                if (lsector_size && use_bsize < lsector_size)