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tools lib fd array: Allow associating an integer cookie with each entry

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We will use this in perf's evlist class so that it can, at
fdarray__filter() time, to unmap the associated ring buffer.

We may need to have further info associated with each fdarray entry, in
that case we'll make that int array a 'union fdarray_priv' one and put a
pointer there so that users can stash whatever they want there. For now,
an int is enough tho.

v2: Add clarification to the per array entry priv area, as well as make
    it a union, which makes usage a bit longer, but if/when we make it
    use more space by allowing per entry pointers existing users source
    code will not have to be changed, just rebuilt.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Link: http://lkml.kernel.org/n/tip-0p00bn83quck3fio3kcs9vca@git.kernel.org
This commit is contained in:
Arnaldo Carvalho de Melo
2014-09-08 11:24:01 -03:00
parent 8239698603
commit 2171a92568
4 changed files with 45 additions and 11 deletions
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16
tools/lib/api/fd/array.h
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@@ -5,11 +5,24 @@
struct pollfd;
/**
* struct fdarray: Array of file descriptors
*
* @priv: Per array entry priv area, users should access just its contents,
* not set it to anything, as it is kept in synch with @entries, being
* realloc'ed, * for instance, in fdarray__{grow,filter}.
*
* I.e. using 'fda->priv[N].idx = * value' where N < fda->nr is ok,
* but doing 'fda->priv = malloc(M)' is not allowed.
*/
struct fdarray {
int nr;
int nr_alloc;
int nr_autogrow;
struct pollfd *entries;
union {
int idx;
} *priv;
};
void fdarray__init(struct fdarray *fda, int nr_autogrow);
@@ -20,7 +33,8 @@ void fdarray__delete(struct fdarray *fda);
int fdarray__add(struct fdarray *fda, int fd, short revents);
int fdarray__poll(struct fdarray *fda, int timeout);
int fdarray__filter(struct fdarray *fda, short revents);
int fdarray__filter(struct fdarray *fda, short revents,
void (*entry_destructor)(struct fdarray *fda, int fd));
int fdarray__grow(struct fdarray *fda, int extra);
int fdarray__fprintf(struct fdarray *fda, FILE *fp);