Split out the code which searches for non-exiting tasks into its own helper. Creating this helper not only makes the code slightly more readable it prepares to move the search out of find_get_context() in a subsequent commit.
Cc: Robin Green <[email protected]> Cc: [email protected] Cc: [email protected] Cc: Prasad <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Will Deacon <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Signed-off-by: Matt Helsley <[email protected]> --- kernel/perf_event.c | 63 ++++++++++++++++++++++++++++++++------------------ 1 files changed, 40 insertions(+), 23 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 440f9ca..3f5309d 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -2015,6 +2015,43 @@ alloc_perf_context(struct pmu *pmu, struct task_struct *task) return ctx; } +static struct task_struct * +find_lively_task_by_vpid(pid_t vpid) +{ + struct task_struct *task; + int err; + + rcu_read_lock(); + if (!vpid) + task = current; + else + task = find_task_by_vpid(vpid); + if (task) + get_task_struct(task); + rcu_read_unlock(); + + if (!task) + return ERR_PTR(-ESRCH); + + /* + * Can't attach events to a dying task. + */ + err = -ESRCH; + if (task->flags & PF_EXITING) + goto errout; + + /* Reuse ptrace permission checks for now. */ + err = -EACCES; + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + goto errout; + + return task; +errout: + put_task_struct(task); + return ERR_PTR(err); + +} + static struct perf_event_context * find_get_context(struct pmu *pmu, pid_t pid, int cpu) { @@ -2047,29 +2084,9 @@ find_get_context(struct pmu *pmu, pid_t pid, int cpu) return ctx; } - rcu_read_lock(); - if (!pid) - task = current; - else - task = find_task_by_vpid(pid); - if (task) - get_task_struct(task); - rcu_read_unlock(); - - if (!task) - return ERR_PTR(-ESRCH); - - /* - * Can't attach events to a dying task. - */ - err = -ESRCH; - if (task->flags & PF_EXITING) - goto errout; - - /* Reuse ptrace permission checks for now. */ - err = -EACCES; - if (!ptrace_may_access(task, PTRACE_MODE_READ)) - goto errout; + task = find_lively_task_by_vpid(pid); + if (IS_ERR(task)) + return (void*)task; err = -EINVAL; ctxn = pmu->task_ctx_nr; -- 1.6.3.3 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
