Add a 'ptr' field to fdarray->priv array.

This feature will be used by following commits, which introduce
muiltiple 'struct perf_mmap' arrays for different types of mapping.

Because of this, during fdarray__filter(), a simple 'idx' is not enough.

Add a pointer cookie that allows to directly associate a 'struct
perf_mmap' pointer to an fdarray entry.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1468485287-33422-3-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Before this patch there's no way to pass arguments to fdarray__filter's
call back function.

This improvement will be used by 'perf record' to support unmapping ring
buffer for both main evlist and overwrite evlist. Without this patch
there's no way to track overwrite evlist from 'struct fdarray'.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1464183898-174512-10-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

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: NArnaldo Carvalho de Melo <acme@redhat.com>

Link: http://lkml.kernel.org/n/tip-0p00bn83quck3fio3kcs9vca@git.kernel.org

The extensible file description array that grew in the perf_evlist class
can be useful for other tools, as it is not something that only evlists
need, so move it to tools/lib/api/fd to ease sharing it.

v2: Don't use {} like in:

 libapi_dirs:
	$(QUIET_MKDIR)mkdir -p $(OUTPUT){fs,fd}/

in Makefiles, as it will not work in some systems, as in ubuntu13.10.

v3: Add fd/*.[ch] to LIBAPIKFS_SOURCES (Fix from Jiri Olsa)

v4: Leave the fcntl(fd, O_NONBLOCK) in the evlist layer, remains to
    be checked if it is really needed there, but has no place in the
    fdarray class (Fix from Jiri Olsa)

v5: Remove evlist details from fdarray grow/filter tests. Improve it a
    bit doing more tests about expected internal state.

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>
Link: http://lkml.kernel.org/n/tip-kleuni3hckbc3s0lu6yb9x40@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>