resume: write offset in /sys/power/resume_offset

Doing this the kernel will hibernate and resume successfully from a swap file.
Stop writing offset to /sys/power/resume, as this is not a parameter
the kernel takes from this input. (Change added by Sven Mueller)

function                                             old     new   delta
resume_main                                          522     561     +39
.rodata                                           103175  103182      +7
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 46/0)               Total: 46 bytes

Signed-off-by: Jordi Pujol Palomer <jordipujolp@gmail.com>
Signed-off-by: Sven Mueller <sven.mueller72+busybox@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/klibc-utils/resume.c b/klibc-utils/resume.c
index 2bf50f9b8..8c4ab26c4 100644
--- a/klibc-utils/resume.c
+++ b/klibc-utils/resume.c
@@ -103,10 +103,17 @@ int resume_main(int argc UNUSED_PARAM, char **argv)
         if (major(resume_device) == 0) {
                 bb_error_msg_and_die("invalid resume device: %s", argv[0]);
         }
+
         ofs = (argv[1] ? xstrtoull(argv[1], 0) : 0);
+        /* Old kernels have no /sys/power/resume_offset, set it only if necessary */
+        if (ofs != 0) {
+                fd = xopen("/sys/power/resume_offset", O_WRONLY);
+                s = xasprintf("%llu", ofs);
+                xwrite_str(fd, s);
+        }
 
         fd = xopen("/sys/power/resume", O_WRONLY);
-        s = xasprintf("%u:%u:%llu", major(resume_device), minor(resume_device), ofs);
+        s = xasprintf("%u:%u", major(resume_device), minor(resume_device));
 
         xwrite_str(fd, s);
         /* if write() returns, resume did not succeed */