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qga/commands-posix: don't do fork()/exec() when suspending via sysfs

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Since commit 246d76eba ("qga: guest_suspend: decoupling pm-utils and sys
logic") pm-utils logic is running in a separate child from the sysfs
logic.  Now when suspending via sysfs we don't really need to do that in
a separate process as we only need to perform one write to /sys/power/state.

Let's just use g_file_set_contents() to simplify things here.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Link: https://lore.kernel.org/r/20240320161648.158226-7-andrey.drobyshev@virtuozzo.com
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>
This commit is contained in:
Andrey Drobyshev 2024-03-20 18:16:47 +02:00 committed by Konstantin Kostiuk
parent 8ef383b460
commit 2048129625
1 changed files with 5 additions and 36 deletions
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41
qga/commands-posix.c
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@ -1928,52 +1928,21 @@ static bool linux_sys_state_supports_mode(SuspendMode mode, Error **errp)
static void linux_sys_state_suspend(SuspendMode mode, Error **errp)
{
Error *local_err = NULL;
g_autoptr(GError) local_gerr = NULL;
const char *sysfile_strs[3] = {"disk", "mem", NULL};
const char *sysfile_str = sysfile_strs[mode];
pid_t pid;
int status;
if (!sysfile_str) {
error_setg(errp, "unknown guest suspend mode");
return;
}
pid = fork();
if (!pid) {
/* child */
int fd;
setsid();
reopen_fd_to_null(0);
reopen_fd_to_null(1);
reopen_fd_to_null(2);
fd = open(LINUX_SYS_STATE_FILE, O_WRONLY);
if (fd < 0) {
_exit(EXIT_FAILURE);
}
if (write(fd, sysfile_str, strlen(sysfile_str)) < 0) {
_exit(EXIT_FAILURE);
}
_exit(EXIT_SUCCESS);
} else if (pid < 0) {
error_setg_errno(errp, errno, "failed to create child process");
if (!g_file_set_contents(LINUX_SYS_STATE_FILE, sysfile_str,
-1, &local_gerr)) {
error_setg(errp, "suspend: cannot write to '%s': %s",
LINUX_SYS_STATE_FILE, local_gerr->message);
return;
}
ga_wait_child(pid, &status, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
if (WEXITSTATUS(status)) {
error_setg(errp, "child process has failed to suspend");
}
}
static void guest_suspend(SuspendMode mode, Error **errp)