Re: perf-core build fails on powerpc

[John Garry]

On 14/03/2018 07:10, John Garry wrote:
> On 13/03/2018 21:18, Sukadev Bhattiprolu wrote:
> > John Garry [john.garry@xxxxxxxxxx] wrote:
> > > On 13/03/2018 20:10, Sukadev Bhattiprolu wrote:
> > >
> > > > Hi John,
> > > >
> > > > I have an xfs file system which seems to have d_type == DT_UNKNOWN
> > > > for all
> > > > entries in 'tools/perf/pmu-events/arch/power8'! readdir(3) says
> > > > ->d_type
> > > > may not be supported by all file systems.
> > > >
> > > > Not relying on ->d_type seems to fix it:
> > >
> > > Hi Sukadev,
> > >
> > > Thanks for debugging this. Jiri Olsa (cc'ed) warned me on this, so I
> > > did add
> > > the check for d_type == DT_UNKNOWN.
> > >
> > > But, if all files have d_type == DT_UNKNOWN, you're code would from
> > > visual
> > > observation look to be same as mine (apart from check for '.' or '..'
> > > filename, which I would say is already covered by stat() and
> > > S_ISDIR()). Or
> > > is d_type value just unreliable?
> >
> > In the current code and with DT_UNKNOWN, is_leaf_dir() returns false when
> > it sees the "." or ".." entries right? In the new code, we skip those and
> > return false only if we find some other directory.
>
> OK, that's the real issue, being the "." and ".." entries.
>
> @Arnaldo, I'll try to send a fix for this today. I just need to make an
> xfs to test. Sorry for the hassle.

Hi Sukadev,

Even with the xfs I have created I still don't see DT_UNKNOWN. So can 
you kindly test this change for me:

diff --git a/tools/perf/pmu-events/jevents.c 
b/tools/perf/pmu-events/jevents.c
index 1c018445e757..9f712dafa0b2 100644
--- a/tools/perf/pmu-events/jevents.c
+++ b/tools/perf/pmu-events/jevents.c
@@ -873,7 +873,10 @@ static int is_leaf_dir(const char *fpath)
                return 0;

        while ((dir = readdir(d)) != NULL) {
-               if (dir->d_type == DT_DIR && dir->d_name[0] != '.') {
+               if (!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, ".."))
+                    continue;
+
+               if (dir->d_type == DT_DIR) {
                        res = 0;
                        break;
                } else if (dir->d_type == DT_UNKNOWN) {


It's quite similar to your change, except keeping the check for DT_DIR.

Much appreciated,
John

> John
>
> > Thanks,
> >
> > Sukadev