lkml.org 
[lkml]   [2000]   [Oct]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectTODO: drivers/pcmcia/ds.c: ds_read & ds_write. SMP locks are missing fix
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 */

/*====================================================================*/
\
 
 \ /
  Last update: 2005-03-22 12:41    [W:0.052 / U:3.380 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site