[PATCH (2.4)] atomic use count for proc_dir_entry

From: Dan Aloni (karrde@callisto.yi.org)
Date: Thu Nov 16 2000 - 16:00:11 EST


(against test11-pre5)

Makes procfs use an atomic use count for dir entries, to avoid using
the Big kernel lock. Axboe says it looks ok.

--- linux/fs/proc/inode.c Wed Jun 21 17:25:17 2000
+++ linux/fs/proc/inode.c Thu Nov 16 19:09:28 2000
@@ -25,7 +25,7 @@
 struct proc_dir_entry * de_get(struct proc_dir_entry *de)
 {
         if (de)
- de->count++;
+ atomic_inc(&de->count);
         return de;
 }
 
@@ -35,20 +35,18 @@
 void de_put(struct proc_dir_entry *de)
 {
         if (de) {
- lock_kernel(); /* FIXME: count should be atomic_t */
- if (!de->count) {
+ if (!atomic_read(&de->count)) {
                         printk("de_put: entry %s already free!\n", de->name);
                         return;
                 }
 
- if (!--de->count) {
+ if (atomic_dec_and_test(&de->count)) {
                         if (de->deleted) {
                                 printk("de_put: deferred delete of %s\n",
                                         de->name);
                                 free_proc_entry(de);
                         }
                 }
- unlock_kernel();
         }
 }
 
@@ -139,7 +137,7 @@
 #if 1
 /* shouldn't ever happen */
 if (de && de->deleted)
-printk("proc_iget: using deleted entry %s, count=%d\n", de->name, de->count);
+printk("proc_iget: using deleted entry %s, count=%d\n", de->name, atomic_read(&de->count));
 #endif
 
         inode = iget(sb, ino);
--- linux/fs/proc/generic.c Tue Nov 14 09:57:01 2000
+++ linux/fs/proc/generic.c Thu Nov 16 20:47:48 2000
@@ -215,7 +215,7 @@
 
 static struct inode_operations proc_link_inode_operations = {
         readlink: proc_readlink,
- follow_link: proc_follow_link
+ follow_link: proc_follow_link,
 };
 
 /*
@@ -574,11 +574,11 @@
                 proc_kill_inodes(de);
                 de->nlink = 0;
                 de->deleted = 1;
- if (!de->count)
+ if (!atomic_read(&de->count))
                         free_proc_entry(de);
                 else {
                         printk("remove_proc_entry: %s/%s busy, count=%d\n",
- parent->name, de->name, de->count);
+ parent->name, de->name, atomic_read(&de->count));
                 }
                 break;
         }
--- linux/fs/proc/root.c Mon May 22 06:34:37 2000
+++ linux/fs/proc/root.c Thu Nov 16 19:22:43 2000
@@ -96,10 +96,12 @@
  * This is the root "inode" in the /proc tree..
  */
 struct proc_dir_entry proc_root = {
- PROC_ROOT_INO, 5, "/proc",
- S_IFDIR | S_IRUGO | S_IXUGO, 2, 0, 0,
- 0, &proc_root_inode_operations, &proc_root_operations,
- NULL, NULL,
- NULL,
- &proc_root, NULL
+ low_ino: PROC_ROOT_INO,
+ namelen: 5,
+ name: "/proc",
+ mode: S_IFDIR | S_IRUGO | S_IXUGO,
+ nlink: 2,
+ proc_iops: &proc_root_inode_operations,
+ proc_fops: &proc_root_operations,
+ parent: &proc_root,
 };
--- linux/kernel/sysctl.c Tue Nov 14 09:57:49 2000
+++ linux/kernel/sysctl.c Thu Nov 16 19:35:02 2000
@@ -571,7 +571,7 @@
                 }
 
                 /* Don't unregister proc entries that are still being used.. */
- if (de->count)
+ if (atomic_read(&de->count))
                         continue;
 
                 table->de = NULL;
--- linux/include/linux/proc_fs.h Thu Nov 16 18:40:47 2000
+++ linux/include/linux/proc_fs.h Thu Nov 16 19:32:18 2000
@@ -67,7 +67,7 @@
         void *data;
         read_proc_t *read_proc;
         write_proc_t *write_proc;
- unsigned int count; /* use count */
+ atomic_t count; /* use count */
         int deleted; /* delete flag */
         kdev_t rdev;
 };
--- linux/drivers/pci/proc.c Tue Nov 14 09:56:55 2000
+++ linux/drivers/pci/proc.c Thu Nov 16 19:37:57 2000
@@ -279,7 +279,7 @@
         struct proc_dir_entry *e;
 
         if ((e = dev->procent)) {
- if (e->count)
+ if (atomic_read(&e->count))
                         return -EBUSY;
                 remove_proc_entry(e->name, dev->bus->procdir);
                 dev->procent = NULL;
--- linux/drivers/nubus/proc.c Sun Nov 28 01:27:48 1999
+++ linux/drivers/nubus/proc.c Thu Nov 16 22:21:34 2000
@@ -148,7 +148,7 @@
         struct proc_dir_entry *e;
 
         if ((e = dev->procdir)) {
- if (e->count)
+ if (atomic_read(&e->count))
                         return -EBUSY;
                 remove_proc_entry(e->name, proc_bus_nubus_dir);
                 dev->procdir = NULL;
--- linux/drivers/i2o/i2o_proc.c Tue Nov 14 09:56:52 2000
+++ linux/drivers/i2o/i2o_proc.c Thu Nov 16 22:44:44 2000
@@ -3237,7 +3237,7 @@
         for(dev=pctrl->devices; dev; dev=dev->next)
                 i2o_proc_remove_device(dev);
 
- if(!pctrl->proc_entry->count)
+ if(!atomic_read(&pctrl->proc_entry->count))
         {
                 sprintf(buff, "iop%d", pctrl->unit);
 
@@ -3257,7 +3257,7 @@
 
         i2o_device_notify_off(dev, &i2o_proc_handler);
         /* Would it be safe to remove _files_ even if they are in use? */
- if((de) && (!de->count))
+ if((de) && (!atomic_read(&de->count)))
         {
                 i2o_proc_remove_entries(generic_dev_entries, de);
                 switch(dev->lct_data.class_id)
@@ -3334,7 +3334,7 @@
                 }
         }
 
- if(!i2o_proc_dir_root->count)
+ if(!atomic_read(&i2o_proc_dir_root->count))
                 remove_proc_entry("i2o", 0);
         else
                 return -1;

-- 
Dan Aloni 
dax@karrde.org

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This archive was generated by hypermail 2b29 : Thu Nov 23 2000 - 21:00:11 EST