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[Qemu-devel] [PULL v2 5/8] blockdev: Add dynamic module loading for bloc
From: |
Max Reitz |
Subject: |
[Qemu-devel] [PULL v2 5/8] blockdev: Add dynamic module loading for block drivers |
Date: |
Sun, 18 Sep 2016 00:06:02 +0200 |
From: Marc Mari <address@hidden>
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 MarĂ <address@hidden>
Signed-off-by: Colin Lord <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Message-id: address@hidden
Reviewed-by: Max Reitz <address@hidden>
Signed-off-by: Max Reitz <address@hidden>
---
Makefile | 3 ---
block.c | 62 +++++++++++++++++++++++++++++++++++++++++++++------
block/Makefile.objs | 3 +--
include/qemu/module.h | 3 +++
util/module.c | 38 +++++++++----------------------
5 files changed, 70 insertions(+), 39 deletions(-)
diff --git a/Makefile b/Makefile
index f2c3b24..6c5c01b 100644
--- a/Makefile
+++ b/Makefile
@@ -248,9 +248,6 @@ Makefile: $(version-obj-y) $(version-lobj-y)
libqemustub.a: $(stub-obj-y)
libqemuutil.a: $(util-obj-y)
-block-modules = $(foreach o,$(block-obj-m),"$(basename $(subst /,-,$o))",) NULL
-util/module.o-cflags = -D'CONFIG_BLOCK_MODULES=$(block-modules)'
-
######################################################################
qemu-img.o: qemu-img-cmds.h
diff --git a/block.c b/block.c
index 66ed1c0..adbe8bb 100644
--- a/block.c
+++ b/block.c
@@ -27,6 +27,7 @@
#include "block/blockjob.h"
#include "block/nbd.h"
#include "qemu/error-report.h"
+#include "module_block.h"
#include "qemu/module.h"
#include "qapi/qmp/qerror.h"
#include "qapi/qmp/qbool.h"
@@ -242,17 +243,40 @@ BlockDriverState *bdrv_new(void)
return bs;
}
-BlockDriver *bdrv_find_format(const char *format_name)
+static BlockDriver *bdrv_do_find_format(const char *format_name)
{
BlockDriver *drv1;
+
QLIST_FOREACH(drv1, &bdrv_drivers, list) {
if (!strcmp(drv1->format_name, format_name)) {
return drv1;
}
}
+
return NULL;
}
+BlockDriver *bdrv_find_format(const char *format_name)
+{
+ BlockDriver *drv1;
+ size_t i;
+
+ drv1 = bdrv_do_find_format(format_name);
+ if (drv1) {
+ return drv1;
+ }
+
+ /* The driver isn't registered, maybe we need to load a module */
+ for (i = 0; i < ARRAY_SIZE(block_driver_modules); ++i) {
+ if (!strcmp(block_driver_modules[i].format_name, format_name)) {
+ block_module_load_one(block_driver_modules[i].library_name);
+ break;
+ }
+ }
+
+ return bdrv_do_find_format(format_name);
+}
+
static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
{
static const char *whitelist_rw[] = {
@@ -461,6 +485,19 @@ static BlockDriver *find_hdev_driver(const char *filename)
return drv;
}
+static BlockDriver *bdrv_do_find_protocol(const char *protocol)
+{
+ BlockDriver *drv1;
+
+ QLIST_FOREACH(drv1, &bdrv_drivers, list) {
+ if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) {
+ return drv1;
+ }
+ }
+
+ return NULL;
+}
+
BlockDriver *bdrv_find_protocol(const char *filename,
bool allow_protocol_prefix,
Error **errp)
@@ -469,6 +506,7 @@ BlockDriver *bdrv_find_protocol(const char *filename,
char protocol[128];
int len;
const char *p;
+ size_t i;
/* TODO Drivers without bdrv_file_open must be specified explicitly */
@@ -495,15 +533,25 @@ BlockDriver *bdrv_find_protocol(const char *filename,
len = sizeof(protocol) - 1;
memcpy(protocol, filename, len);
protocol[len] = '\0';
- QLIST_FOREACH(drv1, &bdrv_drivers, list) {
- if (drv1->protocol_name &&
- !strcmp(drv1->protocol_name, protocol)) {
- return drv1;
+
+ drv1 = bdrv_do_find_protocol(protocol);
+ if (drv1) {
+ return drv1;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(block_driver_modules); ++i) {
+ if (block_driver_modules[i].protocol_name &&
+ !strcmp(block_driver_modules[i].protocol_name, protocol)) {
+ block_module_load_one(block_driver_modules[i].library_name);
+ break;
}
}
- error_setg(errp, "Unknown protocol '%s'", protocol);
- return NULL;
+ drv1 = bdrv_do_find_protocol(protocol);
+ if (!drv1) {
+ error_setg(errp, "Unknown protocol '%s'", protocol);
+ }
+ return drv1;
}
/*
diff --git a/block/Makefile.objs b/block/Makefile.objs
index 55da626..3da471e 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -1,4 +1,4 @@
-block-obj-y += raw_bsd.o qcow.o vdi.o vmdk.o cloop.o bochs.o vpc.o vvfat.o
+block-obj-y += raw_bsd.o qcow.o vdi.o vmdk.o cloop.o bochs.o vpc.o vvfat.o
dmg.o
block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
qcow2-cache.o
block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
block-obj-y += qed-check.o
@@ -40,7 +40,6 @@ gluster.o-libs := $(GLUSTERFS_LIBS)
ssh.o-cflags := $(LIBSSH2_CFLAGS)
ssh.o-libs := $(LIBSSH2_LIBS)
archipelago.o-libs := $(ARCHIPELAGO_LIBS)
-block-obj-m += dmg.o
dmg.o-libs := $(BZIP2_LIBS)
qcow.o-libs := -lz
linux-aio.o-libs := -laio
diff --git a/include/qemu/module.h b/include/qemu/module.h
index 2370708..dc2c9d4 100644
--- a/include/qemu/module.h
+++ b/include/qemu/module.h
@@ -52,9 +52,12 @@ typedef enum {
#define qapi_init(function) module_init(function, MODULE_INIT_QAPI)
#define type_init(function) module_init(function, MODULE_INIT_QOM)
+#define block_module_load_one(lib) module_load_one("block-", lib)
+
void register_module_init(void (*fn)(void), module_init_type type);
void register_dso_module_init(void (*fn)(void), module_init_type type);
void module_call_init(module_init_type type);
+void module_load_one(const char *prefix, const char *lib_name);
#endif
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;
}
}
--
2.9.3
- [Qemu-devel] [PULL v2 0/8] Block layer patches, Max Reitz, 2016/09/17
- [Qemu-devel] [PULL v2 1/8] qemu-img: add the 'dd' subcommand, Max Reitz, 2016/09/17
- [Qemu-devel] [PULL v2 3/8] blockdev: prepare iSCSI block driver for dynamic loading, Max Reitz, 2016/09/17
- [Qemu-devel] [PULL v2 4/8] blockdev: Add dynamic generation of module_block.h, Max Reitz, 2016/09/17
- [Qemu-devel] [PULL v2 2/8] qemu-img: add skip option to dd, Max Reitz, 2016/09/17
- [Qemu-devel] [PULL v2 5/8] blockdev: Add dynamic module loading for block drivers,
Max Reitz <=
- [Qemu-devel] [PULL v2 6/8] blockdev: Modularize nfs block driver, Max Reitz, 2016/09/17
- [Qemu-devel] [PULL v2 7/8] commit: get the overlay node before manipulating the backing chain, Max Reitz, 2016/09/17
- [Qemu-devel] [PULL v2 8/8] iotest 055: refactor and speed up, Max Reitz, 2016/09/17
- Re: [Qemu-devel] [PULL v2 0/8] Block layer patches, Peter Maydell, 2016/09/19