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authorLinus Torvalds <torvalds@linux-foundation.org>2018-03-26 15:39:07 -1000
committerIngo Molnar <mingo@kernel.org>2018-03-28 17:41:50 +0200
commitf67b15037a7a50c57f72e69a6d59941ad90a0f0f (patch)
tree5aec8a6e17ca80a049efb3b0198fef80a7a69c31
parent71eb9ee9596d8df3d5723c3cfc18774c6235e8b1 (diff)
perf/hwbp: Simplify the perf-hwbp code, fix documentation
Annoyingly, modify_user_hw_breakpoint() unnecessarily complicates the modification of a breakpoint - simplify it and remove the pointless local variables. Also update the stale Docbook while at it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/events/hw_breakpoint.c30
1 files changed, 7 insertions, 23 deletions
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 3f8cb1e14588..253ae2da13c3 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -427,16 +427,9 @@ EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
* modify_user_hw_breakpoint - modify a user-space hardware breakpoint
* @bp: the breakpoint structure to modify
* @attr: new breakpoint attributes
- * @triggered: callback to trigger when we hit the breakpoint
- * @tsk: pointer to 'task_struct' of the process to which the address belongs
*/
int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
{
- u64 old_addr = bp->attr.bp_addr;
- u64 old_len = bp->attr.bp_len;
- int old_type = bp->attr.bp_type;
- int err = 0;
-
/*
* modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it
* will not be possible to raise IPIs that invoke __perf_event_disable.
@@ -451,27 +444,18 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att
bp->attr.bp_addr = attr->bp_addr;
bp->attr.bp_type = attr->bp_type;
bp->attr.bp_len = attr->bp_len;
+ bp->attr.disabled = 1;
- if (attr->disabled)
- goto end;
-
- err = validate_hw_breakpoint(bp);
- if (!err)
- perf_event_enable(bp);
+ if (!attr->disabled) {
+ int err = validate_hw_breakpoint(bp);
- if (err) {
- bp->attr.bp_addr = old_addr;
- bp->attr.bp_type = old_type;
- bp->attr.bp_len = old_len;
- if (!bp->attr.disabled)
- perf_event_enable(bp);
+ if (err)
+ return err;
- return err;
+ perf_event_enable(bp);
+ bp->attr.disabled = 0;
}
-end:
- bp->attr.disabled = attr->disabled;
-
return 0;
}
EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);