Merge tag 'v3.10.108' into update

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / staging / comedi / comedi_fops.c

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 924c54c9c31fad595d1cdf9331db17d8c40413f4..2aba2f75fb87ad34ab4c9fcc34573feb3668b04d 100644 (file)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1401,22 +1401,19 @@ static int do_cmd_ioctl(struct comedi_device *dev,
                DPRINTK("subdevice busy\n");
                return -EBUSY;
        }
-       s->busy = file;
 
        /* make sure channel/gain list isn't too long */
        if (cmd.chanlist_len > s->len_chanlist) {
                DPRINTK("channel/gain list too long %u > %d\n",
                        cmd.chanlist_len, s->len_chanlist);
-               ret = -EINVAL;
-               goto cleanup;
+               return -EINVAL;
        }
 
        /* make sure channel/gain list isn't too short */
        if (cmd.chanlist_len < 1) {
                DPRINTK("channel/gain list too short %u < 1\n",
                        cmd.chanlist_len);
-               ret = -EINVAL;
-               goto cleanup;
+               return -EINVAL;
        }
 
        async->cmd = cmd;
@@ -1426,8 +1423,7 @@ static int do_cmd_ioctl(struct comedi_device *dev,
            kmalloc(async->cmd.chanlist_len * sizeof(int), GFP_KERNEL);
        if (!async->cmd.chanlist) {
                DPRINTK("allocation failed\n");
-               ret = -ENOMEM;
-               goto cleanup;
+               return -ENOMEM;
        }
 
        if (copy_from_user(async->cmd.chanlist, user_chanlist,
@@ -1479,6 +1475,9 @@ static int do_cmd_ioctl(struct comedi_device *dev,
 
        comedi_set_subdevice_runflags(s, ~0, SRF_USER | SRF_RUNNING);
 
+       /* set s->busy _after_ setting SRF_RUNNING flag to avoid race with
+        * comedi_read() or comedi_write() */
+       s->busy = file;
        ret = s->do_cmd(dev, s);
        if (ret == 0)
                return 0;
@@ -1693,6 +1692,7 @@ static int do_cancel_ioctl(struct comedi_device *dev, unsigned int arg,
                           void *file)
 {
        struct comedi_subdevice *s;
+       int ret;
 
        if (arg >= dev->n_subdevices)
                return -EINVAL;
@@ -1709,7 +1709,11 @@ static int do_cancel_ioctl(struct comedi_device *dev, unsigned int arg,
        if (s->busy != file)
                return -EBUSY;
 
-       return do_cancel(dev, s);
+       ret = do_cancel(dev, s);
+       if (comedi_get_subdevice_runflags(s) & SRF_USER)
+               wake_up_interruptible(&s->async->wait_head);
+
+       return ret;
 }
 
 /*
@@ -2041,11 +2045,13 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
 
                if (!comedi_is_subdevice_running(s)) {
                        if (count == 0) {
+                               mutex_lock(&dev->mutex);
                                if (comedi_is_subdevice_in_error(s))
                                        retval = -EPIPE;
                                else
                                        retval = 0;
                                do_become_nonbusy(dev, s);
+                               mutex_unlock(&dev->mutex);
                        }
                        break;
                }
@@ -2144,11 +2150,13 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 
                if (n == 0) {
                        if (!comedi_is_subdevice_running(s)) {
+                               mutex_lock(&dev->mutex);
                                do_become_nonbusy(dev, s);
                                if (comedi_is_subdevice_in_error(s))
                                        retval = -EPIPE;
                                else
                                        retval = 0;
+                               mutex_unlock(&dev->mutex);
                                break;
                        }
                        if (file->f_flags & O_NONBLOCK) {
@@ -2186,9 +2194,11 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
                buf += n;
                break;          /* makes device work like a pipe */
        }
-       if (comedi_is_subdevice_idle(s) &&
-           async->buf_read_count - async->buf_write_count == 0) {
-               do_become_nonbusy(dev, s);
+       if (comedi_is_subdevice_idle(s)) {
+               mutex_lock(&dev->mutex);
+               if (async->buf_read_count - async->buf_write_count == 0)
+                       do_become_nonbusy(dev, s);
+               mutex_unlock(&dev->mutex);
        }
        set_current_state(TASK_RUNNING);
        remove_wait_queue(&async->wait_head, &wait);
@@ -2547,15 +2557,13 @@ static int __init comedi_init(void)
 
        comedi_class->dev_attrs = comedi_dev_attrs;
 
-       /* XXX requires /proc interface */
-       comedi_proc_init();
-
        /* create devices files for legacy/manual use */
        for (i = 0; i < comedi_num_legacy_minors; i++) {
                struct comedi_device *dev;
                dev = comedi_alloc_board_minor(NULL);
                if (IS_ERR(dev)) {
                        comedi_cleanup_board_minors();
+                       class_destroy(comedi_class);
                        cdev_del(&comedi_cdev);
                        unregister_chrdev_region(MKDEV(COMEDI_MAJOR, 0),
                                                 COMEDI_NUM_MINORS);
@@ -2566,6 +2574,9 @@ static int __init comedi_init(void)
                }
        }
 
+       /* XXX requires /proc interface */
+       comedi_proc_init();
+
        return 0;
 }
 module_init(comedi_init);