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mei: prevent queuing new flow control credit. 

The MEI  FW can receive only one flow control for read.
Currently the driver only checks if a flow control credit was already
sent and read is pending in the rd_pending queue, but it also has to
check if flow control credit already queued in the write control queue
to prevent sending more than one flow control credits.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Alexander Usyskin 2016-01-07 14:46:36 +02:00 committed by Greg Kroah-Hartman
parent 2bcfdc23c6
commit 13cf988562
1 changed files with 20 additions and 1 deletions
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21
drivers/misc/mei/client.c
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@ -1421,6 +1421,25 @@ out:
return 0;
}
/**
* mei_cl_is_read_fc_cb - check if read cb is waiting for flow control
* for given host client
*
* @cl: host client
*
* Return: true, if found at least one cb.
*/
static bool mei_cl_is_read_fc_cb(struct mei_cl *cl)
{
struct mei_device *dev = cl->dev;
struct mei_cl_cb *cb;
list_for_each_entry(cb, &dev->ctrl_wr_list.list, list)
if (cb->fop_type == MEI_FOP_READ && cb->cl == cl)
return true;
return false;
}
/**
* mei_cl_read_start - the start read client message function.
*
@ -1445,7 +1464,7 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length, struct file *fp)
return -ENODEV;
/* HW currently supports only one pending read */
if (!list_empty(&cl->rd_pending))
if (!list_empty(&cl->rd_pending) || mei_cl_is_read_fc_cb(cl))
return -EBUSY;
if (!mei_me_cl_is_active(cl->me_cl)) {