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.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/pxp/mei_pxp.c b/drivers/misc/mei/pxp/mei_pxp.c
index 2dcb9169e404c3bcbbccc7b44cf51518fb2d221d..c6cdd6a47308ebcc72f34c3891b0b6daeb581cd4 100644 (file)
--- a/drivers/misc/mei/pxp/mei_pxp.c
+++ b/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;