hw-breakpoints: Simplify error handling in breakpoint creation requests
This simplifies the error handling when we create a breakpoint.
We don't need to check the NULL return value corner case anymore
since we have improved perf_event_create_kernel_counter() to
always return an error code in the failure case.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1259210142-5714-3-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index b25f894..75e0cd84 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -657,10 +657,7 @@
tsk, true);
thread->ptrace_bps[i] = NULL;
- if (!bp) { /* incorrect bp, or we have a bug in bp API */
- rc = -EINVAL;
- break;
- }
+ /* Incorrect bp, or we have a bug in bp API */
if (IS_ERR(bp)) {
rc = PTR_ERR(bp);
bp = NULL;
@@ -729,9 +726,6 @@
tsk,
bp->attr.disabled);
}
-
- if (!bp)
- return -EIO;
/*
* CHECKME: the previous code returned -EIO if the addr wasn't a
* valid task virtual addr. The new one will return -EINVAL in this
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 06d372f..dd3fb4a 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -442,7 +442,7 @@
*pevent = bp;
- if (IS_ERR(bp) || !bp) {
+ if (IS_ERR(bp)) {
err = PTR_ERR(bp);
goto fail;
}
@@ -453,7 +453,7 @@
fail:
for_each_possible_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
- if (IS_ERR(*pevent) || !*pevent)
+ if (IS_ERR(*pevent))
break;
unregister_hw_breakpoint(*pevent);
}
diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index 9f040e4..c538b15 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -200,12 +200,9 @@
entry->ksym_hbp = register_wide_hw_breakpoint(entry->ksym_addr,
entry->len, entry->type,
ksym_hbp_handler, true);
- if (IS_ERR(entry->ksym_hbp)) {
- entry->ksym_hbp = NULL;
- ret = PTR_ERR(entry->ksym_hbp);
- }
- if (!entry->ksym_hbp) {
+ if (IS_ERR(entry->ksym_hbp)) {
+ ret = PTR_ERR(entry->ksym_hbp);
printk(KERN_INFO "ksym_tracer request failed. Try again"
" later!!\n");
goto err;
@@ -332,21 +329,16 @@
if (changed) {
unregister_wide_hw_breakpoint(entry->ksym_hbp);
entry->type = op;
+ ret = 0;
if (op > 0) {
entry->ksym_hbp =
register_wide_hw_breakpoint(entry->ksym_addr,
entry->len, entry->type,
ksym_hbp_handler, true);
if (IS_ERR(entry->ksym_hbp))
- entry->ksym_hbp = NULL;
-
- /* modified without problem */
- if (entry->ksym_hbp) {
- ret = 0;
+ ret = PTR_ERR(entry->ksym_hbp);
+ else
goto out;
- }
- } else {
- ret = 0;
}
/* Error or "symbol:---" case: drop it */
ksym_filter_entry_count--;
diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c
index 9506381..ee7f9fb 100644
--- a/samples/hw_breakpoint/data_breakpoint.c
+++ b/samples/hw_breakpoint/data_breakpoint.c
@@ -61,9 +61,6 @@
if (IS_ERR(sample_hbp)) {
ret = PTR_ERR(sample_hbp);
goto fail;
- } else if (!sample_hbp) {
- ret = -EINVAL;
- goto fail;
}
printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name);