[dm-devel] [PATCH v2 12/23] libmultipath: "generic multipath" interface
Benjamin Marzinski
bmarzins at redhat.com
Wed Mar 7 19:01:25 UTC 2018
On Tue, Mar 06, 2018 at 12:14:56AM +0100, Martin Wilck wrote:
> This patch adds a simplified abstract interface to the multipath data structures.
> The idea is to allow "foreign" data structures to be treated by libmultipath
> if they implement the same interface. Currently, the intention is to use this
> only to provide formatted output about from this interface.
>
> This interface assumes only that the data structure is organized in maps
> containing path groups containing paths, and that formatted printing (using
> the wildcards defined in libmultipath) is possible on each level of the data
> structure.
>
> The patch also implements the interface for the internal dm_multipath data
> structure.
>
> The style() method looks a bit exotic, but it's necessary because
> print_multipath_topology() uses different formats depending on the mpp
> properties. This needs to be in the generic interface, too, if we want to
> produce identical output.
>
Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
> libmultipath/Makefile | 2 +-
> libmultipath/dm-generic.c | 70 ++++++++++++++++++++++++
> libmultipath/dm-generic.h | 41 ++++++++++++++
> libmultipath/generic.c | 39 +++++++++++++
> libmultipath/generic.h | 136 ++++++++++++++++++++++++++++++++++++++++++++++
> libmultipath/list.h | 4 ++
> libmultipath/print.c | 33 +++++++++++
> libmultipath/print.h | 12 ++++
> libmultipath/structs.c | 4 ++
> libmultipath/structs.h | 4 ++
> 10 files changed, 344 insertions(+), 1 deletion(-)
> create mode 100644 libmultipath/dm-generic.c
> create mode 100644 libmultipath/dm-generic.h
> create mode 100644 libmultipath/generic.c
> create mode 100644 libmultipath/generic.h
>
> diff --git a/libmultipath/Makefile b/libmultipath/Makefile
> index 25b052729d48..0099d9d6cc39 100644
> --- a/libmultipath/Makefile
> +++ b/libmultipath/Makefile
> @@ -43,7 +43,7 @@ OBJS = memory.o parser.o vector.o devmapper.o callout.o \
> switchgroup.o uxsock.o print.o alias.o log_pthread.o \
> log.o configure.o structs_vec.o sysfs.o prio.o checkers.o \
> lock.o waiter.o file.o wwids.o prioritizers/alua_rtpg.o prkey.o \
> - io_err_stat.o
> + io_err_stat.o dm-generic.o generic.o
>
> all: $(LIBS)
>
> diff --git a/libmultipath/dm-generic.c b/libmultipath/dm-generic.c
> new file mode 100644
> index 000000000000..42a26085d087
> --- /dev/null
> +++ b/libmultipath/dm-generic.c
> @@ -0,0 +1,70 @@
> +/*
> + Copyright (c) 2018 Martin Wilck, SUSE Linux GmbH
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version 2
> + of the License, or (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program; if not, write to the Free Software
> + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
> + USA.
> + */
> +
> +#include <stdint.h>
> +#include <sys/types.h>
> +#include "generic.h"
> +#include "dm-generic.h"
> +#include "structs.h"
> +#include "structs_vec.h"
> +#include "config.h"
> +#include "print.h"
> +
> +static const struct _vector*
> +dm_mp_get_pgs(const struct gen_multipath *gmp)
> +{
> + return vector_convert(NULL, gen_multipath_to_dm(gmp)->pg,
> + struct pathgroup, dm_pathgroup_to_gen);
> +}
> +
> +static void dm_mp_rel_pgs(const struct gen_multipath *gmp,
> + const struct _vector* v)
> +{
> + vector_free_const(v);
> +}
> +
> +static const struct _vector*
> +dm_pg_get_paths(const struct gen_pathgroup *gpg)
> +{
> + return vector_convert(NULL, gen_pathgroup_to_dm(gpg)->paths,
> + struct path, dm_path_to_gen);
> +}
> +
> +static void dm_mp_rel_paths(const struct gen_pathgroup *gpg,
> + const struct _vector* v)
> +{
> + vector_free_const(v);
> +}
> +
> +const struct gen_multipath_ops dm_gen_multipath_ops = {
> + .get_pathgroups = dm_mp_get_pgs,
> + .rel_pathgroups = dm_mp_rel_pgs,
> + .snprint = snprint_multipath_attr,
> + /* .style = snprint_multipath_style, TBD */
> +};
> +
> +const struct gen_pathgroup_ops dm_gen_pathgroup_ops = {
> + .get_paths = dm_pg_get_paths,
> + .rel_paths = dm_mp_rel_paths,
> + .snprint = snprint_pathgroup_attr,
> +};
> +
> +const struct gen_path_ops dm_gen_path_ops = {
> + .snprint = snprint_path_attr,
> +};
> diff --git a/libmultipath/dm-generic.h b/libmultipath/dm-generic.h
> new file mode 100644
> index 000000000000..5d5972406819
> --- /dev/null
> +++ b/libmultipath/dm-generic.h
> @@ -0,0 +1,41 @@
> +/*
> + Copyright (c) 2018 Martin Wilck, SUSE Linux GmbH
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version 2
> + of the License, or (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program; if not, write to the Free Software
> + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
> + USA.
> + */
> +#ifndef _DM_GENERIC_H
> +#define _DM_GENERIC_H
> +#include "generic.h"
> +#include "list.h" /* for container_of */
> +#include "structs.h"
> +
> +#define dm_multipath_to_gen(mpp) (&((mpp)->generic_mp))
> +#define gen_multipath_to_dm(gm) \
> + container_of_const((gm), struct multipath, generic_mp)
> +
> +#define dm_pathgroup_to_gen(pg) (&(pg->generic_pg))
> +#define gen_pathgroup_to_dm(gpg) \
> + container_of_const((gpg), struct pathgroup, generic_pg)
> +
> +#define dm_path_to_gen(pp) (&((pp)->generic_path))
> +#define gen_path_to_dm(gp) \
> + container_of_const((gp), struct path, generic_path)
> +
> +extern const struct gen_multipath_ops dm_gen_multipath_ops;
> +extern const struct gen_pathgroup_ops dm_gen_pathgroup_ops;
> +extern const struct gen_path_ops dm_gen_path_ops;
> +
> +#endif /* _DM_GENERIC_H */
> diff --git a/libmultipath/generic.c b/libmultipath/generic.c
> new file mode 100644
> index 000000000000..45012d0e1d95
> --- /dev/null
> +++ b/libmultipath/generic.c
> @@ -0,0 +1,39 @@
> +/*
> + Copyright (c) 2018 Martin Wilck, SUSE Linux GmbH
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version 2
> + of the License, or (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program; if not, write to the Free Software
> + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
> + USA.
> + */
> +
> +
> +#include <string.h>
> +#include "generic.h"
> +#include "structs.h"
> +
> +int generic_style(const struct gen_multipath* gm,
> + char *buf, int len, int verbosity)
> +{
> + char alias_buf[WWID_SIZE];
> + char wwid_buf[WWID_SIZE];
> + int n = 0;
> +
> + gm->ops->snprint(gm, alias_buf, sizeof(alias_buf), 'n');
> + gm->ops->snprint(gm, wwid_buf, sizeof(wwid_buf), 'w');
> +
> + n += snprintf(buf, len, "%%n %s%%d %%s",
> + strcmp(alias_buf, wwid_buf) ? "(%w) " : "");
> +
> + return (n < len ? n : len - 1);
> +}
> diff --git a/libmultipath/generic.h b/libmultipath/generic.h
> new file mode 100644
> index 000000000000..7f7fe6661c36
> --- /dev/null
> +++ b/libmultipath/generic.h
> @@ -0,0 +1,136 @@
> +/*
> + Copyright (c) 2018 Martin Wilck, SUSE Linux GmbH
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version 2
> + of the License, or (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program; if not, write to the Free Software
> + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
> + USA.
> + */
> +#ifndef _GENERIC_H
> +#define _GENERIC_H
> +#include "vector.h"
> +
> +struct gen_multipath;
> +struct gen_pathgroup;
> +struct gen_path;
> +
> +/**
> + * Methods implemented for gen_multipath "objects"
> + */
> +struct gen_multipath_ops {
> + /**
> + * method: get_pathgroups(gmp)
> + * caller is responsible to returned data using rel_pathgroups()
> + * caller is also responsible to lock the gmp (directly or indirectly)
> + * while working with the return value.
> + * @param gmp: generic multipath object to act on
> + * @returns a vector of const struct gen_pathgroup*
> + */
> + const struct _vector* (*get_pathgroups)(const struct gen_multipath*);
> + /**
> + * method: rel_pathgroups(gmp, v)
> + * free data allocated by get_pathgroups(), if any
> + * @param gmp: generic multipath object to act on
> + * @param v the value returned by get_pathgroups()
> + */
> + void (*rel_pathgroups)(const struct gen_multipath*,
> + const struct _vector*);
> + /**
> + * method: snprint(gmp, buf, len, wildcard)
> + * prints the property of the multipath map matching
> + * the passed-in wildcard character into "buf",
> + * 0-terminated, no more than "len" characters including trailing '\0'.
> + *
> + * @param gmp: generic multipath object to act on
> + * @param buf: output buffer
> + * @param buflen: buffer size
> + * @param wildcard: the multipath wildcard (see print.c)
> + * @returns the number of characters printed (without trailing '\0').
> + */
> + int (*snprint)(const struct gen_multipath*,
> + char *buf, int len, char wildcard);
> + /**
> + * method: style(gmp, buf, len, verbosity)
> + * returns the format string to be used for the multipath object,
> + * defined with the wildcards as defined in print.c
> + * generic_style() should work well in most cases.
> + * @param gmp: generic multipath object to act on
> + * @param buf: output buffer
> + * @param buflen: buffer size
> + * @param verbosity: verbosity level
> + * @returns number of format chars printed
> + */
> + int (*style)(const struct gen_multipath*,
> + char *buf, int len, int verbosity);
> +};
> +
> +/**
> + * Methods implemented for gen_pathgroup "objects"
> + */
> +struct gen_pathgroup_ops {
> + /**
> + * method: get_paths(gpg)
> + * caller is responsible to returned data using rel_paths()
> + * @param gpg: generic pathgroup object to act on
> + * @returns a vector of const struct gen_path*
> + */
> + const struct _vector* (*get_paths)(const struct gen_pathgroup*);
> + /**
> + * method: rel_paths(gpg, v)
> + * free data allocated by get_paths(), if any
> + * @param gmp: generic pathgroup object to act on
> + * @param v the value returned by get_paths()
> + */
> + void (*rel_paths)(const struct gen_pathgroup*, const struct _vector*);
> + /**
> + * Method snprint()
> + * see gen_multipath_ops->snprint() above
> + */
> + int (*snprint)(const struct gen_pathgroup*,
> + char *buf, int len, char wildcard);
> +};
> +
> +struct gen_path_ops {
> + /**
> + * Method snprint()
> + * see gen_multipath_ops->snprint() above
> + */
> + int (*snprint)(const struct gen_path*,
> + char *buf, int len, char wildcard);
> +};
> +
> +struct gen_multipath {
> + const struct gen_multipath_ops *ops;
> +};
> +
> +struct gen_pathgroup {
> + const struct gen_pathgroup_ops *ops;
> +};
> +
> +struct gen_path {
> + const struct gen_path_ops *ops;
> +};
> +
> +/**
> + * Helper functions for setting up the various generic_X_ops
> + */
> +
> +/**
> + * generic_style()
> + * A simple style() method (see above) that should fit most
> + * foreign libraries.
> + */
> +int generic_style(const struct gen_multipath*,
> + char *buf, int len, int verbosity);
> +
> +#endif /* _GENERIC_H */
> diff --git a/libmultipath/list.h b/libmultipath/list.h
> index c9110ac9de7e..ced021f5a633 100644
> --- a/libmultipath/list.h
> +++ b/libmultipath/list.h
> @@ -18,6 +18,10 @@
> * @member: the name of the member within the struct.
> *
> */
> +#define container_of_const(ptr, type, member) ({ \
> + const typeof( ((type *)0)->member ) *__mptr = (ptr); \
> + (const type *)( (const char *)__mptr - offsetof(type,member) );})
> +
> #define container_of(ptr, type, member) ({ \
> typeof( ((type *)0)->member ) *__mptr = (ptr); \
> (type *)( (char *)__mptr - offsetof(type,member) );})
> diff --git a/libmultipath/print.c b/libmultipath/print.c
> index 594ca567e22a..e9b8fdd6e581 100644
> --- a/libmultipath/print.c
> +++ b/libmultipath/print.c
> @@ -756,6 +756,17 @@ mpd_lookup(char wildcard)
> return NULL;
> }
>
> +int snprint_multipath_attr(const struct gen_multipath* gm,
> + char *buf, int len, char wildcard)
> +{
> + const struct multipath *mpp = gen_multipath_to_dm(gm);
> + struct multipath_data *mpd = mpd_lookup(wildcard);
> +
> + if (mpd == NULL)
> + return 0;
> + return mpd->snprint(buf, len, mpp);
> +}
> +
> static struct path_data *
> pd_lookup(char wildcard)
> {
> @@ -768,6 +779,17 @@ pd_lookup(char wildcard)
> return NULL;
> }
>
> +int snprint_path_attr(const struct gen_path* gp,
> + char *buf, int len, char wildcard)
> +{
> + const struct path *pp = gen_path_to_dm(gp);
> + struct path_data *pd = pd_lookup(wildcard);
> +
> + if (pd == NULL)
> + return 0;
> + return pd->snprint(buf, len, pp);
> +}
> +
> static struct pathgroup_data *
> pgd_lookup(char wildcard)
> {
> @@ -780,6 +802,17 @@ pgd_lookup(char wildcard)
> return NULL;
> }
>
> +int snprint_pathgroup_attr(const struct gen_pathgroup* gpg,
> + char *buf, int len, char wildcard)
> +{
> + const struct pathgroup *pg = gen_pathgroup_to_dm(gpg);
> + struct pathgroup_data *pdg = pgd_lookup(wildcard);
> +
> + if (pdg == NULL)
> + return 0;
> + return pdg->snprint(buf, len, pg);
> +}
> +
> int
> snprint_multipath_header (char * line, int len, const char * format)
> {
> diff --git a/libmultipath/print.h b/libmultipath/print.h
> index 02c5b072cc2b..214777c1e4f8 100644
> --- a/libmultipath/print.h
> +++ b/libmultipath/print.h
> @@ -1,3 +1,7 @@
> +#ifndef _PRINT_H
> +#define _PRINT_H
> +#include "dm-generic.h"
> +
> #define PRINT_PATH_LONG "%w %i %d %D %p %t %T %s %o"
> #define PRINT_PATH_INDENT "%i %d %D %t %T %o"
> #define PRINT_PATH_CHECKER "%i %d %D %p %t %T %o %C"
> @@ -122,3 +126,11 @@ int snprint_tgt_wwpn (char *, size_t, const struct path *);
> void print_multipath_topology (struct multipath * mpp, int verbosity);
> void print_all_paths (vector pathvec, int banner);
> void print_all_paths_custo (vector pathvec, int banner, char *fmt);
> +
> +int snprint_path_attr(const struct gen_path* gp,
> + char *buf, int len, char wildcard);
> +int snprint_pathgroup_attr(const struct gen_pathgroup* gpg,
> + char *buf, int len, char wildcard);
> +int snprint_multipath_attr(const struct gen_multipath* gm,
> + char *buf, int len, char wildcard);
> +#endif /* _PRINT_H */
> diff --git a/libmultipath/structs.c b/libmultipath/structs.c
> index 4db08451824d..991095cb2bc1 100644
> --- a/libmultipath/structs.c
> +++ b/libmultipath/structs.c
> @@ -18,6 +18,7 @@
> #include "blacklist.h"
> #include "prio.h"
> #include "prioritizers/alua_spc3.h"
> +#include "dm-generic.h"
>
> struct adapter_group *
> alloc_adaptergroup(void)
> @@ -100,6 +101,7 @@ alloc_path (void)
> pp->tpgs = TPGS_UNDEF;
> pp->priority = PRIO_UNDEF;
> checker_clear(&pp->checker);
> + dm_path_to_gen(pp)->ops = &dm_gen_path_ops;
> }
> return pp;
> }
> @@ -160,6 +162,7 @@ alloc_pathgroup (void)
> pgp = NULL;
> }
>
> + dm_pathgroup_to_gen(pgp)->ops = &dm_gen_pathgroup_ops;
> return pgp;
> }
>
> @@ -200,6 +203,7 @@ alloc_multipath (void)
> mpp->mpcontext = NULL;
> mpp->no_path_retry = NO_PATH_RETRY_UNDEF;
> mpp->fast_io_fail = MP_FAST_IO_FAIL_UNSET;
> + dm_multipath_to_gen(mpp)->ops = &dm_gen_multipath_ops;
> }
> return mpp;
> }
> diff --git a/libmultipath/structs.h b/libmultipath/structs.h
> index bccc845a1222..88a4b7862393 100644
> --- a/libmultipath/structs.h
> +++ b/libmultipath/structs.h
> @@ -6,6 +6,7 @@
>
> #include "prio.h"
> #include "byteorder.h"
> +#include "generic.h"
>
> #define WWID_SIZE 128
> #define SERIAL_SIZE 65
> @@ -256,6 +257,7 @@ struct path {
> int io_err_pathfail_starttime;
> /* configlet pointers */
> struct hwentry * hwe;
> + struct gen_path generic_path;
> };
>
> typedef int (pgpolicyfn) (struct multipath *);
> @@ -332,6 +334,7 @@ struct multipath {
> int prkey_source;
> struct be64 reservation_key;
> unsigned char prflag;
> + struct gen_multipath generic_mp;
> };
>
> struct pathgroup {
> @@ -341,6 +344,7 @@ struct pathgroup {
> int enabled_paths;
> vector paths;
> struct multipath *mpp;
> + struct gen_pathgroup generic_pg;
> };
>
> struct adapter_group {
> --
> 2.16.1
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