mei: pxp: recover from recv fail under memory pressure

Under memory pressure recv fails due to kmalloc failure,
and if drivers(pxp) retry send/receive, send blocks
indefinitely.
Send without recv leaves the channel in a bad state.

Retry send attempt after small timeout and reset the channel if
the retry failed on kmalloc failure too.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20231011110157.247552-3-tomas.winkler@intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/pxp/mei_pxp.c

@@ -11,6 +11,7 @@
  * negotiation messages to ME FW command payloads and vice versa.
  */
 
+#include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/mei.h>
@@ -61,16 +62,38 @@ mei_pxp_receive_message(struct device *dev, void *buffer, size_t size)
 {
 	struct mei_cl_device *cldev;
 	ssize_t byte;
+	bool retry = false;
 
 	if (!dev || !buffer)
 		return -EINVAL;
 
 	cldev = to_mei_cl_device(dev);
 
+retry:
 	byte = mei_cldev_recv(cldev, buffer, size);
 	if (byte < 0) {
 		dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte);
-		return byte;
+		if (byte != -ENOMEM)
+			return byte;
+
+		/* Retry the read when pages are reclaimed */
+		msleep(20);
+		if (!retry) {
+			retry = true;
+			goto retry;
+		} else {
+			dev_warn(dev, "No memory on data receive after retry, trying to reset the channel...\n");
+			byte = mei_cldev_disable(cldev);
+			if (byte < 0)
+				dev_warn(dev, "mei_cldev_disable failed. %zd\n", byte);
+			/*
+			 * Explicitly ignoring disable failure,
+			 * enable may fix the states and succeed
+			 */
+			byte = mei_cldev_enable(cldev);
+			if (byte < 0)
+				dev_err(dev, "mei_cldev_enable failed. %zd\n", byte);
+		}
 	}
 
 	return byte;