[PATCH v4 08/29] tools/libxl: Add save_helper_state pointers to libxl__xc_domain_{save, restore}()

[Andrew Cooper <andrew.cooper3@citrix.com>]

Currently, libxl__xc_domain_{save,restore}() have specific knowledge
of where the libxl__save_helper_state lives inside a
libxl__domain_{create,save}_state object.

In later changes, the logical ownership of the
libxl__save_helper_state will change and will no longer be
d{c,s}s->shs.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>

---
New in v3
---
 tools/libxl/libxl_create.c       |    4 +--
 tools/libxl/libxl_dom.c          |   20 +++++++-------
 tools/libxl/libxl_internal.h     |    5 +++-
 tools/libxl/libxl_save_callout.c |   54 ++++++++++++++++++++------------------
 4 files changed, 44 insertions(+), 39 deletions(-)

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index be13204..7f0ffc6 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -988,7 +988,7 @@ static void domcreate_bootloader_done(libxl__egc *egc,
         rc = ERROR_INVAL;
         goto out;
     }
-    libxl__xc_domain_restore(egc, dcs,
+    libxl__xc_domain_restore(egc, dcs, &dcs->shs,
                              hvm, pae, superpages);
     return;
 
@@ -1000,7 +1000,7 @@ void libxl__srm_callout_callback_restore_results(unsigned long store_mfn,
           unsigned long console_mfn, void *user)
 {
     libxl__save_helper_state *shs = user;
-    libxl__domain_create_state *dcs = CONTAINER_OF(shs, *dcs, shs);
+    libxl__domain_create_state *dcs = shs->caller_state;
     STATE_AO_GC(dcs->ao);
     libxl__domain_build_state *const state = &dcs->build_state;
 
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 8642192..a685b77 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -1121,7 +1121,7 @@ int libxl__toolstack_restore(uint32_t domid, const uint8_t *ptr,
                              uint32_t size, void *user)
 {
     libxl__save_helper_state *shs = user;
-    libxl__domain_create_state *dcs = CONTAINER_OF(shs, *dcs, shs);
+    libxl__domain_create_state *dcs = shs->caller_state;
     STATE_AO_GC(dcs->ao);
     int ret;
     uint32_t version = 0, bufsize;
@@ -1188,7 +1188,7 @@ static void logdirty_init(libxl__logdirty_switch *lds)
                                 libxl__save_helper_state *shs)
 {
     libxl__egc *egc = shs->egc;
-    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
+    libxl__domain_suspend_state *dss = shs->caller_state;
     libxl__logdirty_switch *lds = &dss->logdirty;
     STATE_AO_GC(dss->ao);
     int rc;
@@ -1260,7 +1260,7 @@ static void logdirty_init(libxl__logdirty_switch *lds)
                                 libxl__save_helper_state *shs)
 {
     libxl__egc *egc = shs->egc;
-    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
+    libxl__domain_suspend_state *dss = shs->caller_state;
     STATE_AO_GC(dss->ao);
     int rc;
 
@@ -1279,7 +1279,7 @@ static void logdirty_init(libxl__logdirty_switch *lds)
 {
     libxl__save_helper_state *shs = user;
     libxl__egc *egc = shs->egc;
-    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
+    libxl__domain_suspend_state *dss = shs->caller_state;
     STATE_AO_GC(dss->ao);
 
     switch (libxl__device_model_version_running(gc, domid)) {
@@ -1832,7 +1832,7 @@ static void libxl__domain_suspend_callback(void *data)
 {
     libxl__save_helper_state *shs = data;
     libxl__egc *egc = shs->egc;
-    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
+    libxl__domain_suspend_state *dss = shs->caller_state;
 
     dss->callback_common_done = domain_suspend_callback_common_done;
     domain_suspend_callback_common(egc, dss);
@@ -1859,7 +1859,7 @@ static void libxl__remus_domain_suspend_callback(void *data)
 {
     libxl__save_helper_state *shs = data;
     libxl__egc *egc = shs->egc;
-    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
+    libxl__domain_suspend_state *dss = shs->caller_state;
 
     dss->callback_common_done = remus_domain_suspend_callback_common_done;
     domain_suspend_callback_common(egc, dss);
@@ -1902,7 +1902,7 @@ static void libxl__remus_domain_resume_callback(void *data)
 {
     libxl__save_helper_state *shs = data;
     libxl__egc *egc = shs->egc;
-    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
+    libxl__domain_suspend_state *dss = shs->caller_state;
     STATE_AO_GC(dss->ao);
 
     libxl__remus_devices_state *const rds = &dss->rds;
@@ -1947,8 +1947,8 @@ static void remus_next_checkpoint(libxl__egc *egc, libxl__ev_time *ev,
 static void libxl__remus_domain_checkpoint_callback(void *data)
 {
     libxl__save_helper_state *shs = data;
-    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
-    libxl__egc *egc = dss->shs.egc;
+    libxl__domain_suspend_state *dss = shs->caller_state;
+    libxl__egc *egc = shs->egc;
     STATE_AO_GC(dss->ao);
 
     /* This would go into tailbuf. */
@@ -2117,7 +2117,7 @@ void libxl__domain_suspend(libxl__egc *egc, libxl__domain_suspend_state *dss)
     callbacks->switch_qemu_logdirty = libxl__domain_suspend_common_switch_qemu_logdirty;
     dss->shs.callbacks.save.toolstack_save = libxl__toolstack_save;
 
-    libxl__xc_domain_save(egc, dss);
+    libxl__xc_domain_save(egc, dss, &dss->shs);
     return;
 
  out:
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 8ce3d49..3f1fed8 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3241,7 +3241,9 @@ _hidden void libxl__domain_suspend(libxl__egc *egc,
 
 
 /* calls libxl__xc_domain_suspend_done when done */
-_hidden void libxl__xc_domain_save(libxl__egc*, libxl__domain_suspend_state*);
+_hidden void libxl__xc_domain_save(libxl__egc *egc,
+                                   libxl__domain_suspend_state *dss,
+                                   libxl__save_helper_state *shs);
 /* If rc==0 then retval is the return value from xc_domain_save
  * and errnoval is the errno value it provided.
  * If rc!=0, retval and errnoval are undefined. */
@@ -3265,6 +3267,7 @@ _hidden int libxl__toolstack_save(uint32_t domid, uint8_t **buf,
 /* calls libxl__xc_domain_restore_done when done */
 _hidden void libxl__xc_domain_restore(libxl__egc *egc,
                                       libxl__domain_create_state *dcs,
+                                      libxl__save_helper_state *shs,
                                       int hvm, int pae, int superpages);
 /* If rc==0 then retval is the return value from xc_domain_save
  * and errnoval is the errno value it provided.
diff --git a/tools/libxl/libxl_save_callout.c b/tools/libxl/libxl_save_callout.c
index c56b68c..a5e180c 100644
--- a/tools/libxl/libxl_save_callout.c
+++ b/tools/libxl/libxl_save_callout.c
@@ -42,6 +42,7 @@ static void helper_exited(libxl__egc *egc, libxl__ev_child *ch,
 /*----- entrypoints -----*/
 
 void libxl__xc_domain_restore(libxl__egc *egc, libxl__domain_create_state *dcs,
+                              libxl__save_helper_state *shs,
                               int hvm, int pae, int superpages)
 {
     STATE_AO_GC(dcs->ao);
@@ -51,8 +52,8 @@ void libxl__xc_domain_restore(libxl__egc *egc, libxl__domain_create_state *dcs,
     const int restore_fd = dcs->libxc_fd;
     libxl__domain_build_state *const state = &dcs->build_state;
 
-    unsigned cbflags = libxl__srm_callout_enumcallbacks_restore
-        (&dcs->shs.callbacks.restore.a);
+    unsigned cbflags =
+        libxl__srm_callout_enumcallbacks_restore(&shs->callbacks.restore.a);
 
     const unsigned long argnums[] = {
         domid,
@@ -63,19 +64,20 @@ void libxl__xc_domain_restore(libxl__egc *egc, libxl__domain_create_state *dcs,
         cbflags, dcs->restore_params.checkpointed_stream,
     };
 
-    dcs->shs.ao = ao;
-    dcs->shs.domid = domid;
-    dcs->shs.recv_callback = libxl__srm_callout_received_restore;
-    dcs->shs.completion_callback = libxl__xc_domain_restore_done;
-    dcs->shs.caller_state = dcs;
-    dcs->shs.need_results = 1;
-    dcs->shs.toolstack_data_file = 0;
+    shs->ao = ao;
+    shs->domid = domid;
+    shs->recv_callback = libxl__srm_callout_received_restore;
+    shs->completion_callback = libxl__xc_domain_restore_done;
+    shs->caller_state = dcs;
+    shs->need_results = 1;
+    shs->toolstack_data_file = 0;
 
-    run_helper(egc, &dcs->shs, "--restore-domain", restore_fd, 0,0,
+    run_helper(egc, shs, "--restore-domain", restore_fd, 0, 0,
                argnums, ARRAY_SIZE(argnums));
 }
 
-void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_suspend_state *dss)
+void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_suspend_state *dss,
+                           libxl__save_helper_state *shs)
 {
     STATE_AO_GC(dss->ao);
     int r, rc, toolstack_data_fd = -1;
@@ -84,21 +86,21 @@ void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_suspend_state *dss)
     /* Resources we need to free */
     uint8_t *toolstack_data_buf = 0;
 
-    unsigned cbflags = libxl__srm_callout_enumcallbacks_save
-        (&dss->shs.callbacks.save.a);
+    unsigned cbflags =
+        libxl__srm_callout_enumcallbacks_save(&shs->callbacks.save.a);
 
-    if (dss->shs.callbacks.save.toolstack_save) {
-        r = dss->shs.callbacks.save.toolstack_save
+    if (shs->callbacks.save.toolstack_save) {
+        r = shs->callbacks.save.toolstack_save
             (dss->domid, &toolstack_data_buf, &toolstack_data_len, dss);
         if (r) { rc = ERROR_FAIL; goto out; }
 
-        dss->shs.toolstack_data_file = tmpfile();
-        if (!dss->shs.toolstack_data_file) {
+        shs->toolstack_data_file = tmpfile();
+        if (!shs->toolstack_data_file) {
             LOGE(ERROR, "cannot create toolstack data tmpfile");
             rc = ERROR_FAIL;
             goto out;
         }
-        toolstack_data_fd = fileno(dss->shs.toolstack_data_file);
+        toolstack_data_fd = fileno(shs->toolstack_data_file);
 
         r = libxl_write_exactly(CTX, toolstack_data_fd,
                                 toolstack_data_buf, toolstack_data_len,
@@ -116,23 +118,23 @@ void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_suspend_state *dss)
         cbflags,
     };
 
-    dss->shs.ao = ao;
-    dss->shs.domid = dss->domid;
-    dss->shs.recv_callback = libxl__srm_callout_received_save;
-    dss->shs.completion_callback = libxl__xc_domain_save_done;
-    dss->shs.caller_state = dss;
-    dss->shs.need_results = 0;
+    shs->ao = ao;
+    shs->domid = dss->domid;
+    shs->recv_callback = libxl__srm_callout_received_save;
+    shs->completion_callback = libxl__xc_domain_save_done;
+    shs->caller_state = dss;
+    shs->need_results = 0;
 
     free(toolstack_data_buf);
 
-    run_helper(egc, &dss->shs, "--save-domain", dss->fd,
+    run_helper(egc, shs, "--save-domain", dss->fd,
                &toolstack_data_fd, 1,
                argnums, ARRAY_SIZE(argnums));
     return;
 
  out:
     free(toolstack_data_buf);
-    if (dss->shs.toolstack_data_file) fclose(dss->shs.toolstack_data_file);
+    if (shs->toolstack_data_file) fclose(shs->toolstack_data_file);
 
     libxl__xc_domain_save_done(egc, dss, rc, 0, 0);
 }
-- 
1.7.10.4