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mei: implement fsync

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When write() returns successfully, it is only assumed that a message
was successfully queued. Add fsync syscall implementation to help
user-space ensure that all data is written.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Usyskin 2017-03-20 15:04:06 +02:00 committed by Greg Kroah-Hartman
parent dd04eecc41
commit 58cde1a64c
1 changed files with 72 additions and 0 deletions
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72
drivers/misc/mei/main.c
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@ -585,6 +585,77 @@ static unsigned int mei_poll(struct file *file, poll_table *wait)
return mask;
}
/**
* mei_cl_is_write_queued - check if the client has pending writes.
*
* @cl: writing host client
*
* Return: true if client is writing, false otherwise.
*/
static bool mei_cl_is_write_queued(struct mei_cl *cl)
{
struct mei_device *dev = cl->dev;
struct mei_cl_cb *cb;
list_for_each_entry(cb, &dev->write_list, list)
if (cb->cl == cl)
return true;
list_for_each_entry(cb, &dev->write_waiting_list, list)
if (cb->cl == cl)
return true;
return false;
}
/**
* mei_fsync - the fsync handler
*
* @fp: pointer to file structure
* @start: unused
* @end: unused
* @datasync: unused
*
* Return: 0 on success, -ENODEV if client is not connected
*/
static int mei_fsync(struct file *fp, loff_t start, loff_t end, int datasync)
{
struct mei_cl *cl = fp->private_data;
struct mei_device *dev;
int rets;
if (WARN_ON(!cl || !cl->dev))
return -ENODEV;
dev = cl->dev;
mutex_lock(&dev->device_lock);
if (dev->dev_state != MEI_DEV_ENABLED || !mei_cl_is_connected(cl)) {
rets = -ENODEV;
goto out;
}
while (mei_cl_is_write_queued(cl)) {
mutex_unlock(&dev->device_lock);
rets = wait_event_interruptible(cl->tx_wait,
cl->writing_state == MEI_WRITE_COMPLETE ||
!mei_cl_is_connected(cl));
mutex_lock(&dev->device_lock);
if (rets) {
if (signal_pending(current))
rets = -EINTR;
goto out;
}
if (!mei_cl_is_connected(cl)) {
rets = -ENODEV;
goto out;
}
}
rets = 0;
out:
mutex_unlock(&dev->device_lock);
return rets;
}
/**
* mei_fasync - asynchronous io support
*
@ -700,6 +771,7 @@ static const struct file_operations mei_fops = {
.release = mei_release,
.write = mei_write,
.poll = mei_poll,
.fsync = mei_fsync,
.fasync = mei_fasync,
.llseek = no_llseek
};