libxl: poll: Use poller_get and poller_put for poller_app

This makes the code more regular.  We are going to want to do some
more work in poller_get and poller_put, which work also wants to be
done for poller_app.

Two very minor functional changes:

 * We call malloc an extra time since poller_app is now a pointer

 * ERROR_FAIL on poller_get failing for poller_app is generated in
   libxl_ctx_init rather than passed through by libxl_poller_init
   from libxl__pipe_nonblock.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Jim Fehlig <jfehlig@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Jim Fehlig <jfehlig@suse.com>
(cherry picked from commit aae3765206)

(cherry picked from commit 9f6f513eec)
Conflicts:
	tools/libxl/libxl.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 0348c450fe)

tools/libxl/libxl.c

@@ -50,6 +50,7 @@ int libxl_ctx_alloc(libxl_ctx **pctx, int version,
 
     ctx->osevent_hooks = 0;
 
+    ctx->poller_app = 0;
     LIBXL_LIST_INIT(&ctx->pollers_event);
     LIBXL_LIST_INIT(&ctx->pollers_idle);
 
@@ -83,8 +84,11 @@ int libxl_ctx_alloc(libxl_ctx **pctx, int version,
     rc = libxl__atfork_init(ctx);
     if (rc) goto out;
 
-    rc = libxl__poller_init(ctx, &ctx->poller_app);
-    if (rc) goto out;
+    ctx->poller_app = libxl__poller_get(ctx);
+    if (!ctx->poller_app) {
+        rc = ERROR_FAIL;
+        goto out;
+    }
 
     if ( stat(XENSTORE_PID_FILE, &stat_buf) != 0 ) {
         LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "Is xenstore daemon running?\n"
@@ -160,7 +164,8 @@ int libxl_ctx_free(libxl_ctx *ctx)
     libxl_version_info_dispose(&ctx->version_info);
     if (ctx->xsh) xs_daemon_close(ctx->xsh);
 
-    libxl__poller_dispose(&ctx->poller_app);
+    libxl__poller_put(ctx, ctx->poller_app);
+    ctx->poller_app = NULL;
     assert(LIBXL_LIST_EMPTY(&ctx->pollers_event));
     libxl__poller *poller, *poller_tmp;
     LIBXL_LIST_FOREACH_SAFE(poller, &ctx->pollers_idle, entry, poller_tmp) {

tools/libxl/libxl_event.c

@@ -876,7 +876,7 @@ int libxl_osevent_beforepoll(libxl_ctx *ctx, int *nfds_io,
 {
     EGC_INIT(ctx);
     CTX_LOCK;
-    int rc = beforepoll_internal(gc, &ctx->poller_app,
+    int rc = beforepoll_internal(gc, ctx->poller_app,
                                  nfds_io, fds, timeout_upd, now);
     CTX_UNLOCK;
     EGC_FREE;
@@ -1033,7 +1033,7 @@ void libxl_osevent_afterpoll(libxl_ctx *ctx, int nfds, const struct pollfd *fds,
 {
     EGC_INIT(ctx);
     CTX_LOCK;
-    afterpoll_internal(egc, &ctx->poller_app, nfds, fds, now);
+    afterpoll_internal(egc, ctx->poller_app, nfds, fds, now);
     CTX_UNLOCK;
     EGC_FREE;
 }

tools/libxl/libxl_internal.h

@@ -328,7 +328,7 @@ struct libxl__ctx {
       /* See the comment for OSEVENT_HOOK_INTERN in libxl_event.c
        * for restrictions on the use of the osevent fields. */
 
-    libxl__poller poller_app; /* libxl_osevent_beforepoll and _afterpoll */
+    libxl__poller *poller_app; /* libxl_osevent_beforepoll and _afterpoll */
     LIBXL_LIST_HEAD(, libxl__poller) pollers_event, pollers_idle;
 
     LIBXL_SLIST_HEAD(libxl__osevent_hook_nexi, libxl__osevent_hook_nexus)