Revert "pthreadpool: add pthreadpool_tevent_job_cancel()"
[samba.git] / lib / pthreadpool / pthreadpool_tevent.c
index fbf9c0e..6999730 100644 (file)
  */
 
 #include "replace.h"
-#include "system/threads.h"
+#include "system/filesys.h"
 #include "pthreadpool_tevent.h"
 #include "pthreadpool.h"
 #include "lib/util/tevent_unix.h"
 #include "lib/util/dlinklist.h"
-#include "lib/util/attr.h"
-
-#define PTHREAD_TEVENT_JOB_THREAD_FENCE_INIT(__job) do { \
-       _UNUSED_ const struct pthreadpool_tevent_job *__j = __job; \
-} while(0);
-
-#ifdef WITH_PTHREADPOOL
-/*
- * configure checked we have pthread and atomic_thread_fence() available
- */
-#define __PTHREAD_TEVENT_JOB_THREAD_FENCE(__order) do { \
-       atomic_thread_fence(__order); \
-} while(0)
-#else
-/*
- * we're using lib/pthreadpool/pthreadpool_sync.c ...
- */
-#define __PTHREAD_TEVENT_JOB_THREAD_FENCE(__order) do { } while(0)
-#ifndef HAVE___THREAD
-#define __thread
-#endif
-#endif
-
-#define PTHREAD_TEVENT_JOB_THREAD_FENCE(__job) do { \
-       _UNUSED_ const struct pthreadpool_tevent_job *__j = __job; \
-       __PTHREAD_TEVENT_JOB_THREAD_FENCE(memory_order_seq_cst); \
-} while(0);
-
-#define PTHREAD_TEVENT_JOB_THREAD_FENCE_FINI(__job) do { \
-       _UNUSED_ const struct pthreadpool_tevent_job *__j = __job; \
-} while(0);
 
 struct pthreadpool_tevent_job_state;
 
@@ -107,94 +76,12 @@ struct pthreadpool_tevent_job {
 
        void (*fn)(void *private_data);
        void *private_data;
-
-       /*
-        * Coordination between threads
-        *
-        * There're only one side writing each element
-        * either the main process or the job thread.
-        *
-        * The coordination is done by a full memory
-        * barrier using atomic_thread_fence(memory_order_seq_cst)
-        * wrapped in PTHREAD_TEVENT_JOB_THREAD_FENCE()
-        */
-       struct {
-               /*
-                * 'maycancel'
-                * set when tevent_req_cancel() is called.
-                * (only written by main thread!)
-                */
-               bool maycancel;
-
-               /*
-                * 'orphaned'
-                * set when talloc_free is called on the job request,
-                * tevent_context or pthreadpool_tevent.
-                * (only written by main thread!)
-                */
-               bool orphaned;
-
-               /*
-                * 'started'
-                * set when the job is picked up by a worker thread
-                * (only written by job thread!)
-                */
-               bool started;
-
-               /*
-                * 'executed'
-                * set once the job function returned.
-                * (only written by job thread!)
-                */
-               bool executed;
-
-               /*
-                * 'finished'
-                * set when pthreadpool_tevent_job_signal() is entered
-                * (only written by job thread!)
-                */
-               bool finished;
-
-               /*
-                * 'dropped'
-                * set when pthreadpool_tevent_job_signal() leaves with
-                * orphaned already set.
-                * (only written by job thread!)
-                */
-               bool dropped;
-
-               /*
-                * 'signaled'
-                * set when pthreadpool_tevent_job_signal() leaves normal
-                * and the immediate event was scheduled.
-                * (only written by job thread!)
-                */
-               bool signaled;
-       } needs_fence;
 };
 
 static int pthreadpool_tevent_destructor(struct pthreadpool_tevent *pool);
 
 static void pthreadpool_tevent_job_orphan(struct pthreadpool_tevent_job *job);
 
-static struct pthreadpool_tevent_job *orphaned_jobs;
-
-void pthreadpool_tevent_cleanup_orphaned_jobs(void)
-{
-       struct pthreadpool_tevent_job *job = NULL;
-       struct pthreadpool_tevent_job *njob = NULL;
-
-       for (job = orphaned_jobs; job != NULL; job = njob) {
-               njob = job->next;
-
-               /*
-                * The job destructor keeps the job alive
-                * (and in the list) or removes it from the list.
-                */
-               TALLOC_FREE(job);
-       }
-}
-
 static int pthreadpool_tevent_job_signal(int jobid,
                                         void (*job_fn)(void *private_data),
                                         void *job_private_data,
@@ -206,8 +93,6 @@ int pthreadpool_tevent_init(TALLOC_CTX *mem_ctx, unsigned max_threads,
        struct pthreadpool_tevent *pool;
        int ret;
 
-       pthreadpool_tevent_cleanup_orphaned_jobs();
-
        pool = talloc_zero(mem_ctx, struct pthreadpool_tevent);
        if (pool == NULL) {
                return ENOMEM;
@@ -280,8 +165,6 @@ static int pthreadpool_tevent_destructor(struct pthreadpool_tevent *pool)
        }
        pool->pool = NULL;
 
-       pthreadpool_tevent_cleanup_orphaned_jobs();
-
        return 0;
 }
 
@@ -390,16 +273,15 @@ static void pthreadpool_tevent_job_fn(void *private_data);
 static void pthreadpool_tevent_job_done(struct tevent_context *ctx,
                                        struct tevent_immediate *im,
                                        void *private_data);
-static bool pthreadpool_tevent_job_cancel(struct tevent_req *req);
 
 static int pthreadpool_tevent_job_destructor(struct pthreadpool_tevent_job *job)
 {
        /*
-        * We should never be called with needs_fence.orphaned == false.
+        * We should never be called with state->state != NULL.
         * Only pthreadpool_tevent_job_orphan() will call TALLOC_FREE(job)
         * after detaching from the request state and pool list.
         */
-       if (!job->needs_fence.orphaned) {
+       if (job->state != NULL) {
                abort();
        }
 
@@ -424,17 +306,6 @@ static int pthreadpool_tevent_job_destructor(struct pthreadpool_tevent_job *job)
                }
        }
 
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
-       if (job->needs_fence.dropped) {
-               /*
-                * The signal function saw job->needs_fence.orphaned
-                * before it started the signaling via the immediate
-                * event. So we'll never geht triggered and can
-                * remove job->im and let the whole job go...
-                */
-               TALLOC_FREE(job->im);
-       }
-
        /*
         * pthreadpool_tevent_job_orphan() already removed
         * it from pool->jobs. And we don't need try
@@ -446,27 +317,15 @@ static int pthreadpool_tevent_job_destructor(struct pthreadpool_tevent_job *job)
                /*
                 * state->im still there means, we need to wait for the
                 * immediate event to be triggered or just leak the memory.
-                *
-                * Move it to the orphaned list, if it's not already there.
                 */
                return -1;
        }
 
-       /*
-        * Finally remove from the orphaned_jobs list
-        * and let talloc destroy us.
-        */
-       DLIST_REMOVE(orphaned_jobs, job);
-
-       PTHREAD_TEVENT_JOB_THREAD_FENCE_FINI(job);
        return 0;
 }
 
 static void pthreadpool_tevent_job_orphan(struct pthreadpool_tevent_job *job)
 {
-       job->needs_fence.orphaned = true;
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
-
        /*
         * We're the only function that sets
         * job->state = NULL;
@@ -503,15 +362,6 @@ static void pthreadpool_tevent_job_orphan(struct pthreadpool_tevent_job *job)
         */
        DLIST_REMOVE(job->pool->jobs, job);
 
-       /*
-        * Add it to the list of orphaned jobs,
-        * which may be cleaned up later.
-        *
-        * The destructor removes it from the list
-        * when possible or it denies the free
-        * and keep it in the list.
-        */
-       DLIST_ADD_END(orphaned_jobs, job);
        TALLOC_FREE(job);
 }
 
@@ -550,8 +400,6 @@ struct tevent_req *pthreadpool_tevent_job_send(
        struct pthreadpool_tevent_job *job = NULL;
        int ret;
 
-       pthreadpool_tevent_cleanup_orphaned_jobs();
-
        req = tevent_req_create(mem_ctx, &state,
                                struct pthreadpool_tevent_job_state);
        if (req == NULL) {
@@ -587,7 +435,6 @@ struct tevent_req *pthreadpool_tevent_job_send(
        if (tevent_req_nomem(job->im, req)) {
                return tevent_req_post(req, ev);
        }
-       PTHREAD_TEVENT_JOB_THREAD_FENCE_INIT(job);
        talloc_set_destructor(job, pthreadpool_tevent_job_destructor);
        DLIST_ADD_END(job->pool->jobs, job);
        job->state = state;
@@ -600,80 +447,16 @@ struct tevent_req *pthreadpool_tevent_job_send(
                return tevent_req_post(req, ev);
        }
 
-       tevent_req_set_cancel_fn(req, pthreadpool_tevent_job_cancel);
        return req;
 }
 
-static __thread struct pthreadpool_tevent_job *current_job;
-
-bool pthreadpool_tevent_current_job_canceled(void)
-{
-       if (current_job == NULL) {
-               /*
-                * Should only be called from within
-                * the job function.
-                */
-               abort();
-               return false;
-       }
-
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(current_job);
-       return current_job->needs_fence.maycancel;
-}
-
-bool pthreadpool_tevent_current_job_orphaned(void)
-{
-       if (current_job == NULL) {
-               /*
-                * Should only be called from within
-                * the job function.
-                */
-               abort();
-               return false;
-       }
-
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(current_job);
-       return current_job->needs_fence.orphaned;
-}
-
-bool pthreadpool_tevent_current_job_continue(void)
-{
-       if (current_job == NULL) {
-               /*
-                * Should only be called from within
-                * the job function.
-                */
-               abort();
-               return false;
-       }
-
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(current_job);
-       if (current_job->needs_fence.maycancel) {
-               return false;
-       }
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(current_job);
-       if (current_job->needs_fence.orphaned) {
-               return false;
-       }
-
-       return true;
-}
-
 static void pthreadpool_tevent_job_fn(void *private_data)
 {
        struct pthreadpool_tevent_job *job =
                talloc_get_type_abort(private_data,
                struct pthreadpool_tevent_job);
 
-       current_job = job;
-       job->needs_fence.started = true;
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
-
        job->fn(job->private_data);
-
-       job->needs_fence.executed = true;
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
-       current_job = NULL;
 }
 
 static int pthreadpool_tevent_job_signal(int jobid,
@@ -688,12 +471,8 @@ static int pthreadpool_tevent_job_signal(int jobid,
        struct tevent_threaded_context *tctx = NULL;
        struct pthreadpool_tevent_glue *g = NULL;
 
-       job->needs_fence.finished = true;
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
-       if (job->needs_fence.orphaned) {
+       if (state == NULL) {
                /* Request already gone */
-               job->needs_fence.dropped = true;
-               PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
                return 0;
        }
 
@@ -722,8 +501,6 @@ static int pthreadpool_tevent_job_signal(int jobid,
                                          job);
        }
 
-       job->needs_fence.signaled = true;
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
        return 0;
 }
 
@@ -744,70 +521,11 @@ static void pthreadpool_tevent_job_done(struct tevent_context *ctx,
                return;
        }
 
-       /*
-        * pthreadpool_tevent_job_cleanup()
-        * (called by tevent_req_done() or
-        * tevent_req_error()) will destroy the job.
-        */
-
-       if (job->needs_fence.executed) {
-               tevent_req_done(state->req);
-               return;
-       }
-
-       tevent_req_error(state->req, ENOEXEC);
-       return;
-}
-
-static bool pthreadpool_tevent_job_cancel(struct tevent_req *req)
-{
-       struct pthreadpool_tevent_job_state *state =
-               tevent_req_data(req,
-               struct pthreadpool_tevent_job_state);
-       struct pthreadpool_tevent_job *job = state->job;
-       size_t num;
-
-       if (job == NULL) {
-               return false;
-       }
-
-       job->needs_fence.maycancel = true;
-       PTHREAD_TEVENT_JOB_THREAD_FENCE(job);
-       if (job->needs_fence.started) {
-               /*
-                * It was too late to cancel the request.
-                *
-                * The job still has the chance to look
-                * at pthreadpool_tevent_current_job_canceled()
-                * or pthreadpool_tevent_current_job_continue()
-                */
-               return false;
-       }
-
-       num = pthreadpool_cancel_job(job->pool->pool, 0,
-                                    pthreadpool_tevent_job_fn,
-                                    job);
-       if (num == 0) {
-               /*
-                * It was too late to cancel the request.
-                */
-               return false;
-       }
-
-       /*
-        * It was not too late to cancel the request.
-        *
-        * We can remove job->im, as it will never be used.
-        */
-       TALLOC_FREE(job->im);
-
        /*
         * pthreadpool_tevent_job_cleanup()
         * will destroy the job.
         */
-       tevent_req_defer_callback(req, state->ev);
-       tevent_req_error(req, ECANCELED);
-       return true;
+       tevent_req_done(state->req);
 }
 
 int pthreadpool_tevent_job_recv(struct tevent_req *req)