On Wed, 9 Mar 2005, Jeff Garzik wrote:
> Greg KH wrote:
<snip>
> > +ssize_t tpm_read(struct file * file, char __user * buf,
> > + size_t size, loff_t * off)
> > +{
> > + struct tpm_chip *chip = file->private_data;
> > + int ret_size = -ENODATA;
> > +
> > + if (atomic_read(&chip->data_pending) != 0) { /* Result available */
> > + down(&chip->timer_manipulation_mutex);
> > + del_singleshot_timer_sync(&chip->user_read_timer);
> > + up(&chip->timer_manipulation_mutex);
> > +
> > + down(&chip->buffer_mutex);
> > +
> > + ret_size = atomic_read(&chip->data_pending);
> > + atomic_set(&chip->data_pending, 0);
> > +
> > + if (ret_size == 0) /* timeout just occurred */
> > + ret_size = -ETIME;
> > + else if (ret_size > 0) { /* relay data */
> > + if (size < ret_size)
> > + ret_size = size;
> > +
> > + if (copy_to_user((void __user *) buf,
> > + chip->data_buffer, ret_size)) {
> > + ret_size = -EFAULT;
> > + }
> > + }
> > + up(&chip->buffer_mutex);
> > + }
> > +
> > + return ret_size;
>
> POSIX violation -- when there is no data available, returning a non-standard
> error is silly
<snip>
The patch below fixes this erroneous return code when no data is
available.
Signed-of-by: Kylene Hall <[email protected]>
---
--- linux-2.6.12-rc2/drivers/char/tpm/tpm.c 2005-04-21 17:36:59.000000000 -0500
+++ linux-2.6.12-rc2-tpmdd/drivers/char/tpm/tpm.c 2005-04-21 17:57:39.000000000 -0500
@@ -483,29 +483,19 @@ ssize_t tpm_read(struct file * file, cha
size_t size, loff_t * off)
{
struct tpm_chip *chip = file->private_data;
- int ret_size = -ENODATA;
+ int ret_size;
- if (atomic_read(&chip->data_pending) != 0) { /* Result available */
- down(&chip->timer_manipulation_mutex);
- del_singleshot_timer_sync(&chip->user_read_timer);
- up(&chip->timer_manipulation_mutex);
+ del_singleshot_timer_sync(&chip->user_read_timer);
+ ret_size = atomic_read(&chip->data_pending);
+ atomic_set(&chip->data_pending, 0);
+ if (ret_size > 0) { /* relay data */
+ if (size < ret_size)
+ ret_size = size;
down(&chip->buffer_mutex);
-
- ret_size = atomic_read(&chip->data_pending);
- atomic_set(&chip->data_pending, 0);
-
- if (ret_size == 0) /* timeout just occurred */
- ret_size = -ETIME;
- else if (ret_size > 0) { /* relay data */
- if (size < ret_size)
- ret_size = size;
-
- if (copy_to_user((void __user *) buf,
- chip->data_buffer, ret_size)) {
- ret_size = -EFAULT;
- }
- }
+ if (copy_to_user
+ ((void __user *) buf, chip->data_buffer, ret_size))
+ ret_size = -EFAULT;
up(&chip->buffer_mutex);
}
-
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