dlm: don't limit active work items
[pandora-kernel.git] / fs / dlm / ast.c
index abc49f2..90e5997 100644 (file)
 #include "dlm_internal.h"
 #include "lock.h"
 #include "user.h"
-#include "ast.h"
-
-#define WAKE_ASTS  0
-
-static uint64_t                        ast_seq_count;
-static struct list_head                ast_queue;
-static spinlock_t              ast_queue_lock;
-static struct task_struct *    astd_task;
-static unsigned long           astd_wakeflags;
-static struct mutex            astd_running;
 
+static uint64_t                        dlm_cb_seq;
+static spinlock_t              dlm_cb_seq_spin;
 
 static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
 {
@@ -57,21 +49,13 @@ static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
        }
 }
 
-void dlm_del_ast(struct dlm_lkb *lkb)
-{
-       spin_lock(&ast_queue_lock);
-       if (!list_empty(&lkb->lkb_astqueue))
-               list_del_init(&lkb->lkb_astqueue);
-       spin_unlock(&ast_queue_lock);
-}
-
 int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
                         int status, uint32_t sbflags, uint64_t seq)
 {
        struct dlm_ls *ls = lkb->lkb_resource->res_ls;
        uint64_t prev_seq;
        int prev_mode;
-       int i;
+       int i, rv;
 
        for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
                if (lkb->lkb_callbacks[i].seq)
@@ -100,7 +84,8 @@ int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
                                          mode,
                                          (unsigned long long)prev_seq,
                                          prev_mode);
-                               return 0;
+                               rv = 0;
+                               goto out;
                        }
                }
 
@@ -109,6 +94,7 @@ int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
                lkb->lkb_callbacks[i].mode = mode;
                lkb->lkb_callbacks[i].sb_status = status;
                lkb->lkb_callbacks[i].sb_flags = (sbflags & 0x000000FF);
+               rv = 0;
                break;
        }
 
@@ -117,21 +103,24 @@ int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
                          lkb->lkb_id, (unsigned long long)seq,
                          flags, mode, status, sbflags);
                dlm_dump_lkb_callbacks(lkb);
-               return -1;
+               rv = -1;
+               goto out;
        }
-
-       return 0;
+ out:
+       return rv;
 }
 
 int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
                         struct dlm_callback *cb, int *resid)
 {
-       int i;
+       int i, rv;
 
        *resid = 0;
 
-       if (!lkb->lkb_callbacks[0].seq)
-               return -ENOENT;
+       if (!lkb->lkb_callbacks[0].seq) {
+               rv = -ENOENT;
+               goto out;
+       }
 
        /* oldest undelivered cb is callbacks[0] */
 
@@ -163,7 +152,8 @@ int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
                                  cb->mode,
                                  (unsigned long long)lkb->lkb_last_cast.seq,
                                  lkb->lkb_last_cast.mode);
-                       return 0;
+                       rv = 0;
+                       goto out;
                }
        }
 
@@ -176,171 +166,150 @@ int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
                memcpy(&lkb->lkb_last_bast, cb, sizeof(struct dlm_callback));
                lkb->lkb_last_bast_time = ktime_get();
        }
-
-       return 0;
+       rv = 0;
+ out:
+       return rv;
 }
 
-void dlm_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
-                uint32_t sbflags)
+void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
+               uint32_t sbflags)
 {
-       uint64_t seq;
+       struct dlm_ls *ls = lkb->lkb_resource->res_ls;
+       uint64_t new_seq, prev_seq;
        int rv;
 
-       spin_lock(&ast_queue_lock);
-
-       seq = ++ast_seq_count;
+       spin_lock(&dlm_cb_seq_spin);
+       new_seq = ++dlm_cb_seq;
+       spin_unlock(&dlm_cb_seq_spin);
 
        if (lkb->lkb_flags & DLM_IFL_USER) {
-               spin_unlock(&ast_queue_lock);
-               dlm_user_add_ast(lkb, flags, mode, status, sbflags, seq);
+               dlm_user_add_ast(lkb, flags, mode, status, sbflags, new_seq);
                return;
        }
 
-       rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
-       if (rv < 0) {
-               spin_unlock(&ast_queue_lock);
-               return;
-       }
+       mutex_lock(&lkb->lkb_cb_mutex);
+       prev_seq = lkb->lkb_callbacks[0].seq;
 
-       if (list_empty(&lkb->lkb_astqueue)) {
+       rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, new_seq);
+       if (rv < 0)
+               goto out;
+
+       if (!prev_seq) {
                kref_get(&lkb->lkb_ref);
-               list_add_tail(&lkb->lkb_astqueue, &ast_queue);
-       }
-       spin_unlock(&ast_queue_lock);
 
-       set_bit(WAKE_ASTS, &astd_wakeflags);
-       wake_up_process(astd_task);
+               if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
+                       mutex_lock(&ls->ls_cb_mutex);
+                       list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
+                       mutex_unlock(&ls->ls_cb_mutex);
+               } else {
+                       queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
+               }
+       }
+ out:
+       mutex_unlock(&lkb->lkb_cb_mutex);
 }
 
-static void process_asts(void)
+void dlm_callback_work(struct work_struct *work)
 {
-       struct dlm_ls *ls = NULL;
-       struct dlm_rsb *r = NULL;
-       struct dlm_lkb *lkb;
+       struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
+       struct dlm_ls *ls = lkb->lkb_resource->res_ls;
        void (*castfn) (void *astparam);
        void (*bastfn) (void *astparam, int mode);
        struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
        int i, rv, resid;
 
-repeat:
-       spin_lock(&ast_queue_lock);
-       list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
-               r = lkb->lkb_resource;
-               ls = r->res_ls;
+       memset(&callbacks, 0, sizeof(callbacks));
 
-               if (dlm_locking_stopped(ls))
-                       continue;
-
-               /* we remove from astqueue list and remove everything in
-                  lkb_callbacks before releasing the spinlock so empty
-                  lkb_astqueue is always consistent with empty lkb_callbacks */
-
-               list_del_init(&lkb->lkb_astqueue);
-
-               castfn = lkb->lkb_astfn;
-               bastfn = lkb->lkb_bastfn;
+       mutex_lock(&lkb->lkb_cb_mutex);
+       if (!lkb->lkb_callbacks[0].seq) {
+               /* no callback work exists, shouldn't happen */
+               log_error(ls, "dlm_callback_work %x no work", lkb->lkb_id);
+               dlm_print_lkb(lkb);
+               dlm_dump_lkb_callbacks(lkb);
+       }
 
-               memset(&callbacks, 0, sizeof(callbacks));
+       for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
+               rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
+               if (rv < 0)
+                       break;
+       }
 
-               for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
-                       rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
-                       if (rv < 0)
-                               break;
-               }
-               spin_unlock(&ast_queue_lock);
+       if (resid) {
+               /* cbs remain, loop should have removed all, shouldn't happen */
+               log_error(ls, "dlm_callback_work %x resid %d", lkb->lkb_id,
+                         resid);
+               dlm_print_lkb(lkb);
+               dlm_dump_lkb_callbacks(lkb);
+       }
+       mutex_unlock(&lkb->lkb_cb_mutex);
 
-               if (resid) {
-                       /* shouldn't happen, for loop should have removed all */
-                       log_error(ls, "callback resid %d lkb %x",
-                                 resid, lkb->lkb_id);
-               }
+       castfn = lkb->lkb_astfn;
+       bastfn = lkb->lkb_bastfn;
 
-               for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
-                       if (!callbacks[i].seq)
-                               break;
-                       if (callbacks[i].flags & DLM_CB_SKIP) {
-                               continue;
-                       } else if (callbacks[i].flags & DLM_CB_BAST) {
-                               bastfn(lkb->lkb_astparam, callbacks[i].mode);
-                       } else if (callbacks[i].flags & DLM_CB_CAST) {
-                               lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
-                               lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
-                               castfn(lkb->lkb_astparam);
-                       }
+       for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
+               if (!callbacks[i].seq)
+                       break;
+               if (callbacks[i].flags & DLM_CB_SKIP) {
+                       continue;
+               } else if (callbacks[i].flags & DLM_CB_BAST) {
+                       bastfn(lkb->lkb_astparam, callbacks[i].mode);
+               } else if (callbacks[i].flags & DLM_CB_CAST) {
+                       lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
+                       lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
+                       castfn(lkb->lkb_astparam);
                }
-
-               /* removes ref for ast_queue, may cause lkb to be freed */
-               dlm_put_lkb(lkb);
-
-               cond_resched();
-               goto repeat;
        }
-       spin_unlock(&ast_queue_lock);
-}
-
-static inline int no_asts(void)
-{
-       int ret;
 
-       spin_lock(&ast_queue_lock);
-       ret = list_empty(&ast_queue);
-       spin_unlock(&ast_queue_lock);
-       return ret;
+       /* undo kref_get from dlm_add_callback, may cause lkb to be freed */
+       dlm_put_lkb(lkb);
 }
 
-static int dlm_astd(void *data)
+int dlm_callback_start(struct dlm_ls *ls)
 {
-       while (!kthread_should_stop()) {
-               set_current_state(TASK_INTERRUPTIBLE);
-               if (!test_bit(WAKE_ASTS, &astd_wakeflags))
-                       schedule();
-               set_current_state(TASK_RUNNING);
-
-               mutex_lock(&astd_running);
-               if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags))
-                       process_asts();
-               mutex_unlock(&astd_running);
+       ls->ls_callback_wq = alloc_workqueue("dlm_callback",
+                                            WQ_UNBOUND |
+                                            WQ_MEM_RECLAIM |
+                                            WQ_NON_REENTRANT,
+                                            0);
+       if (!ls->ls_callback_wq) {
+               log_print("can't start dlm_callback workqueue");
+               return -ENOMEM;
        }
        return 0;
 }
 
-void dlm_astd_wake(void)
+void dlm_callback_stop(struct dlm_ls *ls)
 {
-       if (!no_asts()) {
-               set_bit(WAKE_ASTS, &astd_wakeflags);
-               wake_up_process(astd_task);
-       }
+       if (ls->ls_callback_wq)
+               destroy_workqueue(ls->ls_callback_wq);
 }
 
-int dlm_astd_start(void)
+void dlm_callback_suspend(struct dlm_ls *ls)
 {
-       struct task_struct *p;
-       int error = 0;
-
-       INIT_LIST_HEAD(&ast_queue);
-       spin_lock_init(&ast_queue_lock);
-       mutex_init(&astd_running);
-
-       p = kthread_run(dlm_astd, NULL, "dlm_astd");
-       if (IS_ERR(p))
-               error = PTR_ERR(p);
-       else
-               astd_task = p;
-       return error;
-}
+       set_bit(LSFL_CB_DELAY, &ls->ls_flags);
 
-void dlm_astd_stop(void)
-{
-       kthread_stop(astd_task);
+       if (ls->ls_callback_wq)
+               flush_workqueue(ls->ls_callback_wq);
 }
 
-void dlm_astd_suspend(void)
+void dlm_callback_resume(struct dlm_ls *ls)
 {
-       mutex_lock(&astd_running);
-}
+       struct dlm_lkb *lkb, *safe;
+       int count = 0;
 
-void dlm_astd_resume(void)
-{
-       mutex_unlock(&astd_running);
+       clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
+
+       if (!ls->ls_callback_wq)
+               return;
+
+       mutex_lock(&ls->ls_cb_mutex);
+       list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
+               list_del_init(&lkb->lkb_cb_list);
+               queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
+               count++;
+       }
+       mutex_unlock(&ls->ls_cb_mutex);
+
+       log_debug(ls, "dlm_callback_resume %d", count);
 }