[Dazuko-devel] Patch 5/5

[Lino Sanfilippo]

This is a patch from Philipp Rosenberger.

It is not a bugfix but implements polling for dazukofs.
(Although I know that new features are not welcome until dazukofs
is mainline, this one might be useful).


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diff -Nurp dazukofs-3.1.3-patch4/event.c dazukofs-3.1.3-patch5/event.c
--- dazukofs-3.1.3-patch4/event.c       2010-07-08 18:10:41.000000000 +0200
+++ dazukofs-3.1.3-patch5/event.c       2010-07-08 18:18:40.000000000 +0200
@@ -27,6 +27,7 @@
 #include <linux/cred.h>
 #include <linux/pid.h>
 #include <linux/slab.h>
+#include <linux/poll.h>
 
 #include "event.h"
 #include "dev.h"
@@ -357,6 +358,7 @@ static struct dazukofs_group *__create_g
        }
        grp->name_length = strlen(name);
        init_waitqueue_head(&grp->queue);
+       init_waitqueue_head(&grp->poll_queue);
        INIT_LIST_HEAD(&grp->todo_list.list);
        INIT_LIST_HEAD(&grp->working_list.list);
        if (track)
@@ -641,11 +643,11 @@ assign_event_to_groups(struct dazukofs_e
 
                        /* notify someone to handle the event */
                        wake_up(&grp->queue);
-
+                       wake_up(&grp->poll_queue);
+                       
                        i++;
                }
        }
-
        mutex_unlock(&evt->assigned_mutex);
        mutex_unlock(&work_mutex);
 }
@@ -872,6 +874,7 @@ void set_event_pending(struct dazukofs_g
 {
        mutex_lock(&work_mutex);
        list_add(&ec->list, &grp->working_list.list);
+       wake_up(&grp->poll_queue);
        mutex_unlock(&work_mutex);
 }
 
@@ -989,7 +992,7 @@ error_out1:
 }
 
 /**
- * is_event_available - check if an event is available for processing
+ * event_on_todo_list - check if an event is available for processing
  * @grp: the group
  *
  * Description: This function simply checks if there are any events posted
@@ -997,7 +1000,7 @@ error_out1:
  *
  * Returns 0 if there are no events in the todo list.
  */
-static int is_event_available(struct dazukofs_group *grp)
+static int event_on_todo_list(struct dazukofs_group *grp)
 {
        int ret = 0;
 
@@ -1009,6 +1012,27 @@ static int is_event_available(struct daz
        return ret;
 }
 
+/**
+ * event_on_working_list - check if an event is available for processing
+ * @grp: the group
+ *
+ * Description: This function simply checks if there are any events posted
+ * in the group's todo list.
+ *
+ * Returns 0 if there are no events in the todo list.
+ */
+static int event_on_working_list(struct dazukofs_group *grp)
+{
+       int ret = 0;
+
+       mutex_lock(&work_mutex);
+       if (!list_empty(&grp->working_list.list))
+               ret = 1;
+       mutex_unlock(&work_mutex);
+
+       return ret;
+}
+
  * dazukofs_get_event - get an event to process
  * @group_id: id of the group we belong to
  * @event_id: to be filled in with the new event id
@@ -1046,7 +1070,7 @@ int dazukofs_get_event(unsigned long gro
 
        while (1) {
                ret = wait_event_freezable(grp->queue,
-                                          is_event_available(grp) ||
+                                          event_on_todo_list(grp) ||
                                           grp->deprecated);
                if (ret != 0)
                        break;
@@ -1078,8 +1102,41 @@ int dazukofs_get_event(unsigned long gro
                atomic_dec(&grp->use_count);
                return ret;
        }
-
        *pgrp = grp;
        *pec = ec;
        return 0;
 }
+
+void dazukofs_do_poll(unsigned long group_id, struct file *dev_file, 
+                      poll_table *wait, unsigned int *mask)
+{
+       struct dazukofs_group *grp = NULL;
+       struct list_head *pos;
+       int found = 0;
+
+       mutex_lock(&work_mutex);
+       list_for_each(pos, &group_list.list) {
+               grp = list_entry(pos, struct dazukofs_group, list);
+               if (!grp->deprecated && grp->group_id == group_id) {
+                       atomic_inc(&grp->use_count);
+                       found = 1;
+                       break;
+               }
+       }
+       mutex_unlock(&work_mutex);
+
+       if (!found) {
+               *mask = POLLERR; /* is this correct ? */
+               return;
+       }
+
+       poll_wait(dev_file, &grp->poll_queue, wait);
+       if (event_on_todo_list(grp))
+               *mask = POLLIN | POLLRDNORM;
+       if (event_on_working_list(grp))
+               *mask = POLLOUT | POLLWRNORM;
+
+       atomic_dec(&grp->use_count);
+       return;
+}
+
diff -Nurp dazukofs-3.1.3-patch4/event.h dazukofs-3.1.3-patch5/event.h
--- dazukofs-3.1.3-patch4/event.h       2010-07-08 16:39:46.000000000 +0200
+++ dazukofs-3.1.3-patch5/event.h       2010-07-08 16:40:18.000000000 +0200
@@ -23,6 +23,7 @@
 
 #include <linux/list.h>
 #include <linux/wait.h>
+#include <linux/poll.h>
 
 
 struct dazukofs_event {
@@ -54,6 +55,7 @@ struct dazukofs_group {
        unsigned long group_id;
        struct dazukofs_event_container todo_list;
        wait_queue_head_t queue;
+       wait_queue_head_t poll_queue;
        struct dazukofs_event_container working_list;
        atomic_t use_count;
        int tracking;
@@ -64,6 +66,8 @@ struct dazukofs_group {
 extern int dazukofs_init_events(void);
 extern void dazukofs_destroy_events(void);
 
+extern void dazukofs_do_poll(unsigned long group_id, struct file *dev_file, 
+                      poll_table *wait, unsigned int *mask);
 extern void set_event_pending(struct dazukofs_group *grp,
                        struct dazukofs_event_container *ec);
 extern void unclaim_event(struct dazukofs_group *grp, 
diff -Nurp dazukofs-3.1.3-patch4/group_dev.c dazukofs-3.1.3-patch5/group_dev.c
--- dazukofs-3.1.3-patch4/group_dev.c   2010-07-08 15:30:19.000000000 +0200
+++ dazukofs-3.1.3-patch5/group_dev.c   2010-07-08 16:42:59.000000000 +0200
@@ -22,6 +22,7 @@
 #include <linux/fs.h>
 #include <linux/cdev.h>
 #include <linux/uaccess.h>
+#include <linux/poll.h>
 
 #include "dazukofs_fs.h"
 #include "event.h"
@@ -137,6 +138,15 @@ static ssize_t dazukofs_group_write(int 
        return ret;
 }
 
+static unsigned int dazukofs_group_poll(int group_id, struct file *file,
+                                       poll_table *wait)
+{
+       unsigned int mask = 0;
+       dazukofs_do_poll(group_id, file, wait, &mask);
+       return mask;
+}
+
+
 #define DECLARE_GROUP_FOPS(group_id) \
 static int \
 dazukofs_group_open_##group_id(struct inode *inode, struct file *file) \
@@ -161,6 +171,11 @@ dazukofs_group_write_##group_id(struct f
 { \
        return dazukofs_group_write(group_id, file, buffer, length, pos); \
 } \
+static unsigned int \
+dazukofs_group_poll_##group_id(struct file *file, poll_table *wait) \
+{ \
+       return dazukofs_group_poll(group_id, file, wait); \
+} \
 static const struct file_operations group_fops_##group_id = { \
        .owner          = THIS_MODULE, \
        .open           = dazukofs_group_open_##group_id, \
@@ -168,6 +183,7 @@ static const struct file_operations grou
        .read           = dazukofs_group_read_##group_id, \
        .write          = dazukofs_group_write_##group_id, \
        .llseek         = no_llseek, \
+       .poll           = dazukofs_group_poll_##group_id, \
 };
 
 DECLARE_GROUP_FOPS(0)