Patch "cxl/region: Fix state transitions after reset failure" has been added to the 6.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    cxl/region: Fix state transitions after reset failure

to the 6.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cxl-region-fix-state-transitions-after-reset-failure.patch
and it can be found in the queue-6.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 558b58be63a6431a8a75a41b8f45ca40aeb3ee08
Author: Dan Williams <dan.j.williams@xxxxxxxxx>
Date:   Fri Jun 16 18:24:39 2023 -0700

    cxl/region: Fix state transitions after reset failure
    
    [ Upstream commit adfe19738b71a893da62cb2e30bd6bdb4299ea67 ]
    
    Jonathan reports that failed attempts to reset a region (teardown its
    HDM decoder configuration) mistakenly advance the state of the region
    to "not committed". Revert to the previous state of the region on reset
    failure so that the reset can be re-attempted.
    
    Reported-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Closes: http://lore.kernel.org/r/20230316171441.0000205b@xxxxxxxxxx
    Fixes: 176baefb2eb5 ("cxl/hdm: Commit decoder state to hardware")
    Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
    Link: https://lore.kernel.org/r/168696507968.3590522.14484000711718573626.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index fa29bd2ec3227..bfdd424d68970 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -296,9 +296,11 @@ static ssize_t commit_store(struct device *dev, struct device_attribute *attr,
 	if (rc)
 		return rc;
 
-	if (commit)
+	if (commit) {
 		rc = cxl_region_decode_commit(cxlr);
-	else {
+		if (rc == 0)
+			p->state = CXL_CONFIG_COMMIT;
+	} else {
 		p->state = CXL_CONFIG_RESET_PENDING;
 		up_write(&cxl_region_rwsem);
 		device_release_driver(&cxlr->dev);
@@ -308,18 +310,20 @@ static ssize_t commit_store(struct device *dev, struct device_attribute *attr,
 		 * The lock was dropped, so need to revalidate that the reset is
 		 * still pending.
 		 */
-		if (p->state == CXL_CONFIG_RESET_PENDING)
+		if (p->state == CXL_CONFIG_RESET_PENDING) {
 			rc = cxl_region_decode_reset(cxlr, p->interleave_ways);
+			/*
+			 * Revert to committed since there may still be active
+			 * decoders associated with this region, or move forward
+			 * to active to mark the reset successful
+			 */
+			if (rc)
+				p->state = CXL_CONFIG_COMMIT;
+			else
+				p->state = CXL_CONFIG_ACTIVE;
+		}
 	}
 
-	if (rc)
-		goto out;
-
-	if (commit)
-		p->state = CXL_CONFIG_COMMIT;
-	else if (p->state == CXL_CONFIG_RESET_PENDING)
-		p->state = CXL_CONFIG_ACTIVE;
-
 out:
 	up_write(&cxl_region_rwsem);