From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v3 1/4] compat: Add infrastructure to support symbol versioning
Date: Wed, 14 Jan 2015 16:25:19 +0100 [thread overview]
Message-ID: <2338166.O6glFPMYza@xps13> (raw)
In-Reply-To: <1419349913-21674-1-git-send-email-nhorman@tuxdriver.com>
Hi Neil,
2014-12-23 10:51, Neil Horman:
> Add initial pass header files to support symbol versioning.
[...]
> +# Copyright(c) 2010-2014 Neil Horman <nhorman@tuxdriver.com>
Why these dates?
> +# All rights reserved.
I think this line is not required anymore:
http://en.wikipedia.org/wiki/All_rights_reserved
[...]
> +#ifndef _RTE_COMPAT_H_
> +#define _RTE_COMPAT_H_
Why using underscores?
I think it's reserved:
http://en.wikipedia.org/wiki/Include_guard#Use_of_.23include_guards
> +#define SA(x) #x
It should be prefixed. But it's better to use RTE_STR.
> +#ifdef RTE_BUILD_SHARED_LIB
> +
> +/*
> + * Provides backwards compatibility when updating exported functions.
> + * When a symol is exported from a library to provide an API, it also provides a
> + * calling convention (ABI) that is embodied in its name, return type,
> + * arguments, etc. On occasion that function may need to change to accomodate
> + * new functionality, behavior, etc. When that occurs, it is desireable to
> + * allow for backwards compatibility for a time with older binaries that are
> + * dynamically linked to the dpdk. to support that the __vsym and
Should be "To support that," with uppercase and comma.
> + * VERSION_SYMBOL macros are created. They, in conjunction with the
> + * <library>_version.map file for a given library allow for multiple versions of
> + * a symbol to exist in a shared library so that older binaries need not be
> + * immediately recompiled. Their use is outlined in the following example:
> + * Assumptions: DPDK 1.(X) contains a function int foo(char *string)
> + * DPDK 1.(X+1) needs to change foo to be int foo(int index)
> + *
> + * To accomplish this:
> + * 1) Edit lib/<library>/library_version.map to add a DPDK_1.(X+1) node, in which
> + * foo is exported as a global symbol.
> + *
> + * 2) rename the existing function int foo(char *string) to
> + * int __vsym foo_v18(char *string)
> + *
> + * 3) Add this macro immediately below the function
> + * VERSION_SYMBOL(foo, _v18, 1.8);
> + *
> + * 4) Implement a new version of foo.
> + * char foo(int value, int otherval) { ...}
> + *
> + * 5) Mark the newest version as the default version
> + * BIND_DEFAULT_SYMBOL(foo, 1.9);
> + *
> + */
Thanks for this good tutorial.
> +#define VERSION_SYMBOL(b, e, v) __asm__(".symver " SA(b) SA(e) ", "SA(b)"@DPDK_"SA(v))
> +#define BASE_SYMBOL(b, n) __asm__(".symver " SA(n) ", "SA(b)"@")
> +#define BIND_DEFAULT_SYMBOL(b, v) __asm__(".symver " SA(b) ", "SA(b)"@@DPDK_"SA(v))
> +#define __vsym __attribute__((used))
OK. It would be simpler to read if b, e, v and n were formally defined in a comment.
> +#else
[...]
> +/*
> + * RTE_BUILD_SHARED_LIB
> + */
This type of comment is strange. It makes me think that we are in the case
RTE_BUILD_SHARED_LIB=y
> +#endif
[...]
> +
> +CPU_LDFLAGS += --version-script=$(EXPORT_MAP)
Why this variable name? VERSION_SCRIPT or VERSION_MAP seems more appropriate.
> +
> endif
>
> +
Why this newline?
> _BUILD = $(LIB)
--
Thomas
next prev parent reply other threads:[~2015-01-14 15:25 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-20 21:01 [dpdk-dev] Add DSO symbol versioning to supportbackwards compatibility Neil Horman
2014-12-20 21:01 ` [dpdk-dev] [PATCH 1/4] compat: Add infrastructure to support symbol versioning Neil Horman
2014-12-22 14:01 ` Gonzalez Monroy, Sergio
2014-12-22 16:22 ` Neil Horman
2014-12-22 16:34 ` Neil Horman
2014-12-22 17:09 ` Gonzalez Monroy, Sergio
2014-12-22 19:00 ` Neil Horman
2014-12-22 20:04 ` Neil Horman
2014-12-20 21:01 ` [dpdk-dev] [PATCH 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2014-12-20 21:01 ` [dpdk-dev] [PATCH 3/4] Add library version extenstion Neil Horman
2014-12-20 21:01 ` [dpdk-dev] [PATCH 4/4] docs: Add ABI documentation Neil Horman
2014-12-22 20:24 ` [dpdk-dev] [PATCH v2 1/4] compat: Add infrastructure to support symbol versioning Neil Horman
2014-12-22 20:24 ` [dpdk-dev] [PATCH v2 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2014-12-22 20:24 ` [dpdk-dev] [PATCH v2 3/4] Add library version extenstion Neil Horman
2014-12-23 13:05 ` Gonzalez Monroy, Sergio
2014-12-23 15:50 ` Neil Horman
2014-12-22 20:24 ` [dpdk-dev] [PATCH v2 4/4] docs: Add ABI documentation Neil Horman
2014-12-23 9:48 ` Iremonger, Bernard
2014-12-23 13:01 ` Neil Horman
2014-12-23 13:27 ` [dpdk-dev] [PATCH v2 1/4] compat: Add infrastructure to support symbol versioning Gonzalez Monroy, Sergio
2014-12-23 15:50 ` Neil Horman
2014-12-23 15:51 ` [dpdk-dev] [PATCH v3 " Neil Horman
2014-12-23 15:51 ` [dpdk-dev] [PATCH v3 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2014-12-29 16:21 ` Sergio Gonzalez Monroy
2015-01-14 15:29 ` Thomas Monjalon
2015-01-14 16:24 ` Neil Horman
2014-12-23 15:51 ` [dpdk-dev] [PATCH v3 3/4] Add library version extenstion Neil Horman
2014-12-23 16:44 ` Gonzalez Monroy, Sergio
2014-12-23 17:08 ` Neil Horman
2014-12-29 16:23 ` Sergio Gonzalez Monroy
2015-01-14 15:48 ` Thomas Monjalon
2014-12-23 15:51 ` [dpdk-dev] [PATCH v3 4/4] docs: Add ABI documentation Neil Horman
2014-12-29 16:24 ` Sergio Gonzalez Monroy
2015-01-14 15:59 ` Thomas Monjalon
2015-01-14 20:07 ` Neil Horman
2015-01-16 13:34 ` Thomas Monjalon
2014-12-29 16:20 ` [dpdk-dev] [PATCH v3 1/4] compat: Add infrastructure to support symbol versioning Sergio Gonzalez Monroy
2015-01-14 15:25 ` Thomas Monjalon [this message]
2015-01-14 20:29 ` Neil Horman
2015-01-09 12:35 ` [dpdk-dev] Add DSO symbol versioning to supportbackwards compatibility Neil Horman
2015-01-15 19:35 ` [dpdk-dev] [PATCH v4 1/4] compat: Add infrastructure to support symbol versioning Neil Horman
2015-01-15 19:35 ` [dpdk-dev] [PATCH v4 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2015-01-15 19:35 ` [dpdk-dev] [PATCH v4 3/4] Add library version extenstion Neil Horman
2015-01-15 19:35 ` [dpdk-dev] [PATCH v4 4/4] docs: Add ABI documentation Neil Horman
2015-01-30 17:13 ` [dpdk-dev] [PATCH v4 1/4] compat: Add infrastructure to support symbol versioning Gray, Mark D
2015-01-16 15:33 ` [dpdk-dev] [PATCH v5 " Neil Horman
2015-01-16 15:33 ` [dpdk-dev] [PATCH v5 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2015-01-16 15:33 ` [dpdk-dev] [PATCH v5 3/4] Add library version extenstion Neil Horman
2015-01-16 15:33 ` [dpdk-dev] [PATCH v5 4/4] docs: Add ABI documentation Neil Horman
2015-01-20 7:14 ` Thomas Monjalon
2015-01-20 10:47 ` Bruce Richardson
2015-01-20 13:37 ` Iremonger, Bernard
2015-01-20 13:46 ` Thomas Monjalon
2015-01-20 14:24 ` Neil Horman
2015-01-20 14:29 ` Butler, Siobhan A
2015-01-20 14:41 ` Neil Horman
2015-01-20 14:50 ` Butler, Siobhan A
2015-01-20 15:30 ` Neil Horman
2015-01-20 14:32 ` O'driscoll, Tim
2015-01-20 14:00 ` Thomas Monjalon
2015-01-20 14:37 ` Neil Horman
2015-01-20 15:06 ` Thomas Monjalon
2015-01-20 15:35 ` Neil Horman
2015-01-20 21:17 ` [dpdk-dev] [PATCH v6 1/4] compat: Add infrastructure to support symbol versioning Neil Horman
2015-01-20 21:17 ` [dpdk-dev] [PATCH v6 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2015-01-20 21:17 ` [dpdk-dev] [PATCH v6 3/4] Add library version extenstion Neil Horman
2015-01-20 21:17 ` [dpdk-dev] [PATCH v6 4/4] docs: Add ABI documentation Neil Horman
2015-01-21 10:13 ` Iremonger, Bernard
2015-01-21 10:25 ` Thomas Monjalon
2015-01-21 14:59 ` Neil Horman
2015-01-21 16:05 ` Thomas Monjalon
2015-01-21 19:43 ` Neil Horman
2015-01-21 22:24 ` Thomas Monjalon
2015-01-22 19:21 ` Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 01/26] version: 2.0.0-rc0 Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 02/26] mk: fix link to static combined library Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 03/26] eal: fix check for power of 2 in 0 case Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 04/26] ethdev: fix missing parenthesis in mac check Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 05/26] mem: search only dpdk hugetlbfs maps Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 06/26] log: remove unnecessary stubs Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 07/26] vfio: avoid enabling while the module is not loaded Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 08/26] bond: fix vlan flag interpretation Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 09/26] app/testpmd: remove duplicated function for list parsing Neil Horman
2015-01-21 20:57 ` [dpdk-dev] [PATCH v7 10/26] nic_uio: fix thread structure compatibility for future FreeBSD Neil Horman
2015-01-21 20:58 ` [dpdk-dev] [PATCH v7 01/26] version: 2.0.0-rc0 Neil Horman
2015-01-21 20:59 ` [dpdk-dev] [PATCH v7 1/4] compat: Add infrastructure to support symbol versioning Neil Horman
2015-01-21 20:59 ` [dpdk-dev] [PATCH v7 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2015-01-21 20:59 ` [dpdk-dev] [PATCH v7 3/4] Add library version extenstion Neil Horman
2015-01-21 20:59 ` [dpdk-dev] [PATCH v7 4/4] docs: Add ABI documentation Neil Horman
2015-01-22 10:56 ` Iremonger, Bernard
2015-01-22 15:37 ` Neil Horman
2015-01-22 15:49 ` [dpdk-dev] [PATCH v8 1/4] compat: Add infrastructure to support symbol versioning Neil Horman
2015-01-22 15:49 ` [dpdk-dev] [PATCH v8 2/4] Provide initial versioning for all DPDK libraries Neil Horman
2015-01-22 15:49 ` [dpdk-dev] [PATCH v8 3/4] Add library version extenstion Neil Horman
2015-01-22 15:49 ` [dpdk-dev] [PATCH v8 4/4] docs: Add ABI documentation Neil Horman
2015-01-22 16:46 ` Butler, Siobhan A
[not found] ` <1422898822-16422-1-git-send-email-nhorman@tuxdriver.com>
[not found] ` <1422898822-16422-4-git-send-email-nhorman@tuxdriver.com>
2015-02-03 15:24 ` [dpdk-dev] [PATCH v9 " Thomas Monjalon
2015-02-03 16:01 ` [dpdk-dev] Add DSO symbol versioning to supportbackwards compatibility Thomas Monjalon
2015-02-03 20:20 ` Neil Horman
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