TODO: drivers/pcmcia/ds.c: ds_read & ds_write. SMP locks are missing fix

From: Yong Chi (yong.chi@qwest.com)
Date: Thu Oct 12 2000 - 10:38:11 EST

Hopefully this will do for SMP locks. =)

Todo list also said that on UP, sleep_on() use is unsafe. It uses
"interruptible_sleep_on()" and "wake_up_interruptible()" calls. Are they
not safe on UP?

Thanks


--- ds.c.bak Wed Oct 11 13:05:16 2000
+++ ds.c Thu Oct 12 11:25:20 2000
@@ -95,6 +95,7 @@
     u_int user_magic;
     int event_head, event_tail;
     event_t event[MAX_EVENTS];
+ spinlock_t lock;
     struct user_info_t *next;
 } user_info_t;
 
@@ -567,6 +568,7 @@
     user->event_tail = user->event_head = 0;
     user->next = s->user;
     user->user_magic = USER_MAGIC;
+ spin_lock_init(&user->lock);
     s->user = user;
     file->private_data = user;
     
@@ -616,6 +618,7 @@
     socket_t i = MINOR(file->f_dentry->d_inode->i_rdev);
     socket_info_t *s;
     user_info_t *user;
+ ssize_t retval=4;
 
     DEBUG(2, "ds_read(socket %d)\n", i);
     
@@ -625,16 +628,23 @@
         return -EINVAL;
     s = &socket_table[i];
     user = file->private_data;
- if (CHECK_USER(user))
- return -EIO;
-
+ spin_lock(&user->lock);
+ if (CHECK_USER(user)) {
+ retval= -EIO;
+ goto read_out;
+ }
+
     if (queue_empty(user)) {
         interruptible_sleep_on(&s->queue);
         if (signal_pending(current))
- return -EINTR;
+ retval= -EINTR;
+ goto read_out;
     }
     put_user(get_queued_event(user), (int *)buf);
- return 4;
+
+read_out:
+ spin_unlock(&user->lock);
+ return retval;
 } /* ds_read */
 
 /*====================================================================*/
@@ -645,6 +655,7 @@
     socket_t i = MINOR(file->f_dentry->d_inode->i_rdev);
     socket_info_t *s;
     user_info_t *user;
+ ssize_t retval=4;
 
     DEBUG(2, "ds_write(socket %d)\n", i);
     
@@ -656,18 +667,25 @@
         return -EBADF;
     s = &socket_table[i];
     user = file->private_data;
- if (CHECK_USER(user))
- return -EIO;
+ spin_lock(&user->lock);
+ if (CHECK_USER(user)) {
+ retval= -EIO;
+ goto write_out;
+ }
 
     if (s->req_pending) {
         s->req_pending--;
         get_user(s->req_result, (int *)buf);
         if ((s->req_result != 0) || (s->req_pending == 0))
             wake_up_interruptible(&s->request);
- } else
- return -EIO;
+ } else {
+ retval= -EIO;
+ goto write_out;
+ }
 
- return 4;
+write_out:
+ spin_unlock(&user->lock);
+ return retval;
 } /* ds_write */
 
 /*====================================================================*/

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This archive was generated by hypermail 2b29 : Sun Oct 15 2000 - 21:00:23 EST