88d88798b7
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 <markmb@redhat.com>
Signed-off-by: Colin Lord <clord@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1471008424-16465-4-git-send-email-clord@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
[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 <mreitz@redhat.com>
64 lines
2.1 KiB
C
64 lines
2.1 KiB
C
/*
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* QEMU Module Infrastructure
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*
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* Copyright IBM, Corp. 2009
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#ifndef QEMU_MODULE_H
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#define QEMU_MODULE_H
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#define DSO_STAMP_FUN glue(qemu_stamp, CONFIG_STAMP)
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#define DSO_STAMP_FUN_STR stringify(DSO_STAMP_FUN)
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#ifdef BUILD_DSO
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void DSO_STAMP_FUN(void);
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/* This is a dummy symbol to identify a loaded DSO as a QEMU module, so we can
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* distinguish "version mismatch" from "not a QEMU module", when the stamp
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* check fails during module loading */
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void qemu_module_dummy(void);
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#define module_init(function, type) \
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static void __attribute__((constructor)) do_qemu_init_ ## function(void) \
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{ \
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register_dso_module_init(function, type); \
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}
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#else
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/* This should not be used directly. Use block_init etc. instead. */
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#define module_init(function, type) \
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static void __attribute__((constructor)) do_qemu_init_ ## function(void) \
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{ \
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register_module_init(function, type); \
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}
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#endif
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typedef enum {
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MODULE_INIT_BLOCK,
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MODULE_INIT_OPTS,
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MODULE_INIT_QAPI,
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MODULE_INIT_QOM,
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MODULE_INIT_MAX
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} module_init_type;
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#define block_init(function) module_init(function, MODULE_INIT_BLOCK)
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#define opts_init(function) module_init(function, MODULE_INIT_OPTS)
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#define qapi_init(function) module_init(function, MODULE_INIT_QAPI)
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#define type_init(function) module_init(function, MODULE_INIT_QOM)
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#define block_module_load_one(lib) module_load_one("block-", lib)
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void register_module_init(void (*fn)(void), module_init_type type);
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void register_dso_module_init(void (*fn)(void), module_init_type type);
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void module_call_init(module_init_type type);
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void module_load_one(const char *prefix, const char *lib_name);
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#endif
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