From 88d88798b7efeb0be15b1a60e58b1f8ba4c2f700 Mon Sep 17 00:00:00 2001 From: Marc Mari Date: Fri, 12 Aug 2016 09:27:03 -0400 Subject: blockdev: Add dynamic module loading for block drivers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Extend the current module interface to allow for block drivers to be loaded dynamically on request. The only block drivers that can be converted into modules are the drivers that don't perform any init operation except for registering themselves. In addition, only the protocol drivers are being modularized, as they are the only ones which see significant performance benefits. The format drivers do not generally link to external libraries, so modularizing them is of no benefit from a performance perspective. All the necessary module information is located in a new structure found in module_block.h This spoils the purpose of 5505e8b76f (block/dmg: make it modular). Before this patch, if module build is enabled, block-dmg.so is linked to libbz2, whereas the main binary is not. In downstream, theoretically, it means only the qemu-block-extra package depends on libbz2, while the main QEMU package needn't to. With this patch, we (temporarily) change the case so that the main QEMU depends on libbz2 again. Signed-off-by: Marc Marí Signed-off-by: Colin Lord Reviewed-by: Stefan Hajnoczi Message-id: 1471008424-16465-4-git-send-email-clord@redhat.com Reviewed-by: Max Reitz [mreitz: Do a signed comparison against the length of block_driver_modules[], so it will not cause a compile error when empty] Signed-off-by: Max Reitz --- util/module.c | 38 +++++++++++--------------------------- 1 file changed, 11 insertions(+), 27 deletions(-) (limited to 'util/module.c') diff --git a/util/module.c b/util/module.c index 86e3f7a..a5f7fbd 100644 --- a/util/module.c +++ b/util/module.c @@ -87,14 +87,11 @@ void register_dso_module_init(void (*fn)(void), module_init_type type) QTAILQ_INSERT_TAIL(&dso_init_list, e, node); } -static void module_load(module_init_type type); - void module_call_init(module_init_type type) { ModuleTypeList *l; ModuleEntry *e; - module_load(type); l = find_type(type); QTAILQ_FOREACH(e, l, node) { @@ -145,6 +142,7 @@ static int module_load_file(const char *fname) ret = -EINVAL; } else { QTAILQ_FOREACH(e, &dso_init_list, node) { + e->init(); register_module_init(e->init, e->type); } ret = 0; @@ -159,14 +157,10 @@ out: } #endif -static void module_load(module_init_type type) +void module_load_one(const char *prefix, const char *lib_name) { #ifdef CONFIG_MODULES char *fname = NULL; - const char **mp; - static const char *block_modules[] = { - CONFIG_BLOCK_MODULES - }; char *exec_dir; char *dirs[3]; int i = 0; @@ -177,15 +171,6 @@ static void module_load(module_init_type type) return; } - switch (type) { - case MODULE_INIT_BLOCK: - mp = block_modules; - break; - default: - /* no other types have dynamic modules for now*/ - return; - } - exec_dir = qemu_get_exec_dir(); dirs[i++] = g_strdup_printf("%s", CONFIG_QEMU_MODDIR); dirs[i++] = g_strdup_printf("%s/..", exec_dir ? : ""); @@ -194,16 +179,15 @@ static void module_load(module_init_type type) g_free(exec_dir); exec_dir = NULL; - for ( ; *mp; mp++) { - for (i = 0; i < ARRAY_SIZE(dirs); i++) { - fname = g_strdup_printf("%s/%s%s", dirs[i], *mp, HOST_DSOSUF); - ret = module_load_file(fname); - g_free(fname); - fname = NULL; - /* Try loading until loaded a module file */ - if (!ret) { - break; - } + for (i = 0; i < ARRAY_SIZE(dirs); i++) { + fname = g_strdup_printf("%s/%s%s%s", + dirs[i], prefix, lib_name, HOST_DSOSUF); + ret = module_load_file(fname); + g_free(fname); + fname = NULL; + /* Try loading until loaded a module file */ + if (!ret) { + break; } } -- cgit v1.1