Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / drivers / scsi / cxlflash / superpipe.c

diff --git a/kernel/drivers/scsi/cxlflash/superpipe.c b/kernel/drivers/scsi/cxlflash/superpipe.c
index cac2e6a..babe7cc 100644 (file)
--- 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);