Commit 8a1898db authored by Hendrik Brueckner's avatar Hendrik Brueckner Committed by Ingo Molnar

perf/aux: Correct return code of rb_alloc_aux() if !has_aux(ev)

If the event for which an AUX area is about to be allocated, does
not support setting up an AUX area, rb_alloc_aux() return -ENOTSUPP.

This error condition is being returned unfiltered to the user space,
and, for example, the perf tools fails with:

  failed to mmap with 524 (INTERNAL ERROR: strerror_r(524, 0x3fff497a1c8, 512)=22)

This error can be easily seen with "perf record -m 128,256 -e cpu-clock".

The 524 error code maps to -ENOTSUPP (in rb_alloc_aux()). The -ENOTSUPP
error code shall be only used within the kernel.  So the correct error
code would then be -EOPNOTSUPP.

With this commit, the perf tool then reports:

  failed to mmap with 95 (Operation not supported)

which is more clear.
Signed-off-by: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pu Hou <bjhoupu@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Cc: acme@kernel.org
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/1497954399-6355-1-git-send-email-brueckner@linux.vnet.ibm.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9705596d
...@@ -580,7 +580,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event, ...@@ -580,7 +580,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event,
int ret = -ENOMEM, max_order = 0; int ret = -ENOMEM, max_order = 0;
if (!has_aux(event)) if (!has_aux(event))
return -ENOTSUPP; return -EOPNOTSUPP;
if (event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) { if (event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) {
/* /*
......
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