From 13cf988562b0c7f06e0016bea2b5304358397702 Mon Sep 17 00:00:00 2001 From: Alexander Usyskin Date: Thu, 7 Jan 2016 14:46:36 +0200 Subject: [PATCH] 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 Signed-off-by: Tomas Winkler Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/client.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c index a6c87c7..72e3261 100644 --- a/drivers/misc/mei/client.c +++ b/drivers/misc/mei/client.c @@ -1422,6 +1422,25 @@ out: } /** + * 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. * * @cl: host client @@ -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)) { -- 2.7.4