From 605bfaee9078cd0b01d83402315389839ee4bb5c Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 26 Nov 2009 05:35:42 +0100 Subject: [PATCH] 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 Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Paul Mackerras Cc: Steven Rostedt Cc: Prasad LKML-Reference: <1259210142-5714-3-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/ptrace.c | 8 +------- kernel/hw_breakpoint.c | 4 ++-- kernel/trace/trace_ksym.c | 18 +++++------------- samples/hw_breakpoint/data_breakpoint.c | 3 --- 4 files changed, 8 insertions(+), 25 deletions(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index b25f8947ed7a..75e0cd847bd6 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -657,10 +657,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data) 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 06d372fc026d..dd3fb4a999d3 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 9f040e42f516..c538b15b95d6 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) { + 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 @@ 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 95063818bcf4..ee7f9fbaffbd 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);