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authorFrederic Weisbecker <fweisbec@gmail.com>2009-11-26 05:35:42 +0100
committerIngo Molnar <mingo@elte.hu>2009-11-26 09:29:21 +0100
commit605bfaee9078cd0b01d83402315389839ee4bb5c (patch)
tree35c3af269b37347b689b3b212fc99d4ae9f719e5
parentc6567f642e20bcc79abed030f44be5b0d6da2ded (diff)
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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>
-rw-r--r--arch/x86/kernel/ptrace.c8
-rw-r--r--kernel/hw_breakpoint.c4
-rw-r--r--kernel/trace/trace_ksym.c16
-rw-r--r--samples/hw_breakpoint/data_breakpoint.c3
4 files changed, 7 insertions, 24 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index b25f8947ed7..75e0cd847bd 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -657,10 +657,7 @@ restore:
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 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
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 06d372fc026..dd3fb4a999d 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -442,7 +442,7 @@ register_wide_hw_breakpoint(unsigned long addr,
*pevent = bp;
- if (IS_ERR(bp) || !bp) {
+ if (IS_ERR(bp)) {
err = PTR_ERR(bp);
goto fail;
}
@@ -453,7 +453,7 @@ register_wide_hw_breakpoint(unsigned long addr,
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 9f040e42f51..c538b15b95d 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -200,12 +200,9 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)
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) {
printk(KERN_INFO "ksym_tracer request failed. Try again"
" later!!\n");
goto err;
@@ -332,21 +329,16 @@ static ssize_t ksym_trace_filter_write(struct file *file,
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 95063818bcf..ee7f9fbaffb 100644
--- a/samples/hw_breakpoint/data_breakpoint.c
+++ b/samples/hw_breakpoint/data_breakpoint.c
@@ -61,9 +61,6 @@ static int __init hw_break_module_init(void)
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);