Messages in this thread Patch in this message | | | Date | Thu, 02 Nov 2023 16:09:23 +0100 | From | Peter Zijlstra <> | Subject | [PATCH 04/13] perf: Simplify event_function*() |
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Use guards to reduce gotos and simplify control flow.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/events/core.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -214,6 +214,19 @@ struct event_function_struct { void *data; }; +typedef struct { + struct perf_cpu_context *cpuctx; + struct perf_event_context *ctx; +} class_perf_ctx_lock_t; + +static inline void class_perf_ctx_lock_destructor(class_perf_ctx_lock_t *_T) +{ perf_ctx_unlock(_T->cpuctx, _T->ctx); } + +static inline class_perf_ctx_lock_t +class_perf_ctx_lock_constructor(struct perf_cpu_context *cpuctx, + struct perf_event_context *ctx) +{ perf_ctx_lock(cpuctx, ctx); return (class_perf_ctx_lock_t){ cpuctx, ctx }; } + static int event_function(void *info) { struct event_function_struct *efs = info; @@ -221,20 +234,17 @@ static int event_function(void *info) struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_context *task_ctx = cpuctx->task_ctx; - int ret = 0; lockdep_assert_irqs_disabled(); + guard(perf_ctx_lock)(cpuctx, task_ctx); - perf_ctx_lock(cpuctx, task_ctx); /* * Since we do the IPI call without holding ctx->lock things can have * changed, double check we hit the task we set out to hit. */ if (ctx->task) { - if (ctx->task != current) { - ret = -ESRCH; - goto unlock; - } + if (ctx->task != current) + return -ESRCH; /* * We only use event_function_call() on established contexts, @@ -254,10 +264,8 @@ static int event_function(void *info) } efs->func(event, cpuctx, ctx, efs->data); -unlock: - perf_ctx_unlock(cpuctx, task_ctx); - return ret; + return 0; } static void event_function_call(struct perf_event *event, event_f func, void *data) @@ -329,11 +337,11 @@ static void event_function_local(struct task_ctx = ctx; } - perf_ctx_lock(cpuctx, task_ctx); + guard(perf_ctx_lock)(cpuctx, task_ctx); task = ctx->task; if (task == TASK_TOMBSTONE) - goto unlock; + return; if (task) { /* @@ -343,18 +351,16 @@ static void event_function_local(struct */ if (ctx->is_active) { if (WARN_ON_ONCE(task != current)) - goto unlock; + return; if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) - goto unlock; + return; } } else { WARN_ON_ONCE(&cpuctx->ctx != ctx); } func(event, cpuctx, ctx, data); -unlock: - perf_ctx_unlock(cpuctx, task_ctx); } #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
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