Commit ee5cb393 authored by Alexander Usyskin's avatar Alexander Usyskin Committed by Greg Kroah-Hartman
Browse files

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: default avatarAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: default avatarAlan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: default avatarTomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20231011110157.247552-3-tomas.winkler@intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cf439721

drivers/misc/mei/pxp/mei_pxp.c

+24 −1
Original line number Diff line number Diff line
@@ -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);

		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;