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[char-misc-next 10/12] mei: enqueue consecutive reads

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From: Alexander Usyskin <alexander.usyskin@intel.com>

The FW supports only one pending read per host client, in order to
support  issuing of consecutive reads the driver  queues read requests
internally and send them to the firmware after pending one has
completed.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
 drivers/misc/mei/interrupt.c |  3 +++
 drivers/misc/mei/main.c      | 39 +++++++++++++++++++--------------------
 2 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 36382d782e20..bf745e03f21e 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -209,6 +209,9 @@ static int mei_cl_irq_read(struct mei_cl *cl, struct mei_cl_cb *cb,
 	int slots;
 	int ret;
 
+	if (!list_empty(&cl->rd_pending))
+		return 0;
+
 	msg_slots = mei_data2slots(sizeof(struct hbm_flow_control));
 	slots = mei_hbuf_empty_slots(dev);
 
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index d698ba32357c..650061b6ab9b 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -139,9 +139,8 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 	struct mei_cl *cl = file->private_data;
 	struct mei_device *dev;
 	struct mei_cl_cb *cb = NULL;
+	bool nonblock = !!(file->f_flags & O_NONBLOCK);
 	int rets;
-	int err;
-
 
 	if (WARN_ON(!cl || !cl->dev))
 		return -ENODEV;
@@ -177,25 +176,29 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 	if (*offset > 0)
 		*offset = 0;
 
-	err = mei_cl_read_start(cl, length, file);
-	if (err && err != -EBUSY) {
-		cl_dbg(dev, cl, "mei start read failure status = %d\n", err);
-		rets = err;
+	rets = mei_cl_read_start(cl, length, file);
+	if (rets && rets != -EBUSY) {
+		cl_dbg(dev, cl, "mei start read failure status = %d\n", rets);
 		goto out;
 	}
 
-	/* synchronized under device mutex */
-	if (!waitqueue_active(&cl->rx_wait)) {
-		if (file->f_flags & O_NONBLOCK) {
-			rets = -EAGAIN;
-			goto out;
-		}
+	if (nonblock) {
+		rets = -EAGAIN;
+		goto out;
+	}
+
+	if (rets == -EBUSY &&
+	    !mei_cl_enqueue_ctrl_wr_cb(cl, length, MEI_FOP_READ, file)) {
+		rets = -ENOMEM;
+		goto out;
+	}
 
+	do {
 		mutex_unlock(&dev->device_lock);
 
 		if (wait_event_interruptible(cl->rx_wait,
-				(!list_empty(&cl->rd_completed)) ||
-				(!mei_cl_is_connected(cl)))) {
+					     (!list_empty(&cl->rd_completed)) ||
+					     (!mei_cl_is_connected(cl)))) {
 
 			if (signal_pending(current))
 				return -EINTR;
@@ -207,13 +210,9 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 			rets = -ENODEV;
 			goto out;
 		}
-	}
 
-	cb = mei_cl_read_cb(cl, file);
-	if (!cb) {
-		rets = 0;
-		goto out;
-	}
+		cb = mei_cl_read_cb(cl, file);
+	} while (!cb);
 
 copy_buffer:
 	/* now copy the data to user space */
-- 
2.7.4

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Thread

[char-misc-next 00/12] mei: rx enhancements Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 02/12] mei: add file pointer to the host client structure Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 09/12] mei: add wrapper for queuing control commands. Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 04/12] mei: amthif: drop mei_clear_lists function Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 05/12] mei: drop redundant krealloc and checks in irq read Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 11/12] mei: amthif: drop mei_amthif_read Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 01/12] mei: move read cb to complete queue if not connected Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 08/12] mei: use consistent naming for TX control flow credits Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 07/12] mei: rx flow control counter Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 12/12] mei: drop unused file transaction states Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 10/12] mei: enqueue consecutive reads Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:00 +0200
  [char-misc-next 06/12] mei: prepare read cb for fixed address clients on the receive path only. Tomas Winkler <tomas.winkler@intel.com> - 2016-07-22 15:10 +0200
  RE: [char-misc-next 00/12] mei: rx enhancements "Winkler, Tomas" <tomas.winkler@intel.com> - 2016-07-25 01:00 +0200
    Re: [char-misc-next 00/12] mei: rx enhancements Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-07-25 01:30 +0200

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