Changeset 230260ac in mainline for uspace/srv/vfs/vfs_register.c

Timestamp:

2009-06-09T22:27:43Z (15 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

0e31a2b

Parents:

041186f

Message:

Make VFS use the new synchronization for fibrils. Now there should be no (or
only secondary) fibril serialization. Code reorganized not to hold the phone
lock during async_wait_for() in most cases. Tested on ia32. On amd64, VFS
crashes, but I think it is an unrelated problem.

File:

• uspace/srv/vfs/vfs_register.c (modified) (16 diffs)

uspace/srv/vfs/vfs_register.c

@@ -46 +46 @@
 #include <ctype.h>
 #include <bool.h>
-#include <futex.h>
+#include <fibril_sync.h>
 #include <adt/list.h>
 #include <as.h>
@@ -53 +53 @@
 #include "vfs.h"
 
-atomic_t fs_head_futex = FUTEX_INITIALIZER;
+FIBRIL_MUTEX_INITIALIZE(fs_head_lock);
 link_t fs_head;
 
@@ -160 +160 @@
         }
         link_initialize(&fs_info->fs_link);
-        futex_initialize(&fs_info->phone_futex, 1);
+        fibril_mutex_initialize(&fs_info->phone_lock);
                 
         rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);
@@ -181 +181 @@
         }
                 
-        futex_down(&fs_head_futex);
-        fibril_inc_sercount();
+        fibril_mutex_lock(&fs_head_lock);
 
         /*
@@ -192 +191 @@
                  */
                 dprintf("FS is already registered.\n");
-                fibril_dec_sercount();
-                futex_up(&fs_head_futex);
+                fibril_mutex_unlock(&fs_head_lock);
                 free(fs_info);
                 ipc_answer_0(callid, EEXISTS);
@@ -215 +213 @@
                 dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
                 list_remove(&fs_info->fs_link);
-                fibril_dec_sercount();
-                futex_up(&fs_head_futex);
+                fibril_mutex_unlock(&fs_head_lock);
                 free(fs_info);
                 ipc_answer_0(callid, EINVAL);
@@ -234 +231 @@
                 dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
                 list_remove(&fs_info->fs_link);
-                fibril_dec_sercount();
-                futex_up(&fs_head_futex);
+                fibril_mutex_unlock(&fs_head_lock);
                 ipc_hangup(fs_info->phone);
                 free(fs_info);
@@ -249 +245 @@
                 dprintf("Client suggests wrong size of PFB, size = %d\n", size);
                 list_remove(&fs_info->fs_link);
-                fibril_dec_sercount();
-                futex_up(&fs_head_futex);
+                fibril_mutex_unlock(&fs_head_lock);
                 ipc_hangup(fs_info->phone);
                 free(fs_info);
@@ -274 +269 @@
         ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
         
-        fibril_dec_sercount();
-        futex_up(&fs_head_futex);
+        fibril_mutex_unlock(&fs_head_lock);
         
         dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
@@ -298 +292 @@
          * phone_futex and keep it until vfs_release_phone().
          */
-        futex_down(&fs_head_futex);
+        fibril_mutex_lock(&fs_head_lock);
         link_t *cur;
         fs_info_t *fs;
@@ -304 +298 @@
                 fs = list_get_instance(cur, fs_info_t, fs_link);
                 if (fs->fs_handle == handle) {
-                        futex_up(&fs_head_futex);
-                        /*
-                         * For now, take the futex unconditionally.
-                         * Oh yeah, serialization rocks.
-                         * It will be up'ed in vfs_release_phone().
-                         */
-                        futex_down(&fs->phone_futex);
-                        /*
-                         * Avoid deadlock with other fibrils in the same thread
-                         * by disabling fibril preemption.
-                         */
-                        fibril_inc_sercount();
+                        fibril_mutex_unlock(&fs_head_lock);
+                        fibril_mutex_lock(&fs->phone_lock);
                         return fs->phone;
                 }
         }
-        futex_up(&fs_head_futex);
+        fibril_mutex_unlock(&fs_head_lock);
         return 0;
 }
@@ -331 +315 @@
         bool found = false;
 
-        /*
-         * Undo the fibril_inc_sercount() done in vfs_grab_phone().
-         */
-        fibril_dec_sercount();
-        
-        futex_down(&fs_head_futex);
+        fibril_mutex_lock(&fs_head_lock);
         link_t *cur;
         for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
@@ -342 +321 @@
                 if (fs->phone == phone) {
                         found = true;
-                        futex_up(&fs_head_futex);
-                        futex_up(&fs->phone_futex);
+                        fibril_mutex_unlock(&fs_head_lock);
+                        fibril_mutex_unlock(&fs->phone_lock);
                         return;
                 }
         }
-        futex_up(&fs_head_futex);
+        fibril_mutex_unlock(&fs_head_lock);
 
         /*
@@ -358 +337 @@
  *
  * @param name          File system name.
- * @param lock          If true, the function will down and up the
- *                      fs_head_futex.
+ * @param lock          If true, the function will lock and unlock the
+ *                      fs_head_lock.
  *
  * @return              File system handle or zero if file system not found.
@@ -368 +347 @@
         
         if (lock)
-                futex_down(&fs_head_futex);
+                fibril_mutex_lock(&fs_head_lock);
         link_t *cur;
         for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
@@ -378 +357 @@
         }
         if (lock)
-                futex_up(&fs_head_futex);
+                fibril_mutex_unlock(&fs_head_lock);
         return handle;
 }