Upgrade to 4.4.50-rt62

The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e

where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt

c) One patch has been backported thus revert the patch before applying.

 filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff  |patch -p1 --dry-run

Upstream status: backport

Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/kernel/drivers/scsi/cxlflash/superpipe.c b/kernel/drivers/scsi/cxlflash/superpipe.c
index cac2e6a50..babe7ccc1 100644
--- a/kernel/drivers/scsi/cxlflash/superpipe.c
+++ b/kernel/drivers/scsi/cxlflash/superpipe.c
@@ -1380,7 +1380,7 @@ static int cxlflash_disk_attach(struct scsi_device *sdev,
 	}
 
 	ctxid = cxl_process_element(ctx);
-	if (unlikely((ctxid > MAX_CONTEXT) || (ctxid < 0))) {
+	if (unlikely((ctxid >= MAX_CONTEXT) || (ctxid < 0))) {
 		dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid);
 		rc = -EPERM;
 		goto err2;
@@ -1508,7 +1508,7 @@ static int recover_context(struct cxlflash_cfg *cfg, struct ctx_info *ctxi)
 	}
 
 	ctxid = cxl_process_element(ctx);
-	if (unlikely((ctxid > MAX_CONTEXT) || (ctxid < 0))) {
+	if (unlikely((ctxid >= MAX_CONTEXT) || (ctxid < 0))) {
 		dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid);
 		rc = -EPERM;
 		goto err1;
@@ -1590,6 +1590,13 @@ err1:
  * place at the same time and the failure was due to CXL services being
  * unable to keep up.
  *
+ * As this routine is called on ioctl context, it holds the ioctl r/w
+ * semaphore that is used to drain ioctls in recovery scenarios. The
+ * implementation to achieve the pacing described above (a local mutex)
+ * requires that the ioctl r/w semaphore be dropped and reacquired to
+ * avoid a 3-way deadlock when multiple process recoveries operate in
+ * parallel.
+ *
  * Because a user can detect an error condition before the kernel, it is
  * quite possible for this routine to act as the kernel's EEH detection
  * source (MMIO read of mbox_r). Because of this, there is a window of
@@ -1617,9 +1624,17 @@ static int cxlflash_afu_recover(struct scsi_device *sdev,
 	int rc = 0;
 
 	atomic_inc(&cfg->recovery_threads);
+	up_read(&cfg->ioctl_rwsem);
 	rc = mutex_lock_interruptible(mutex);
+	down_read(&cfg->ioctl_rwsem);
 	if (rc)
 		goto out;
+	rc = check_state(cfg);
+	if (rc) {
+		dev_err(dev, "%s: Failed state! rc=%d\n", __func__, rc);
+		rc = -ENODEV;
+		goto out;
+	}
 
 	dev_dbg(dev, "%s: reason 0x%016llX rctxid=%016llX\n",
 		__func__, recover->reason, rctxid);