Merge tag 'powerpc-4.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "Fixes marked for stable:
   - Prevent unlikely crash in copro_calculate_slb() (Frederic Barrat)
   - cxl: Prevent adapter reset if an active context exists (Vaibhav Jain)

  Fixes for code merged this cycle:
   - Fix boot on systems with uncompressed kernel image (Heiner Kallweit)
   - Drop dump_numa_memory_topology() (Michael Ellerman)
   - Fix numa topology console print (Aneesh Kumar K.V)
   - Ignore the pkey system calls for now (Stephen Rothwell)"

* tag 'powerpc-4.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc: Ignore the pkey system calls for now
  powerpc: Fix numa topology console print
  powerpc/mm: Drop dump_numa_memory_topology()
  cxl: Prevent adapter reset if an active context exists
  powerpc/boot: Fix boot on systems with uncompressed kernel image
  powerpc/mm: Prevent unlikely crash in copro_calculate_slb()

1 files changed, 41 insertions, 1 deletions

diff --git a/drivers/misc/cxl/main.c b/drivers/misc/cxl/main.c
index d9be23b24aa3..62e0dfb5f15b 100644
--- a/drivers/misc/cxl/main.c
+++ b/drivers/misc/cxl/main.c
@@ -243,8 +243,10 @@ struct cxl *cxl_alloc_adapter(void)
 	if (dev_set_name(&adapter->dev, "card%i", adapter->adapter_num))
 		goto err2;
 
-	return adapter;
+	/* start with context lock taken */
+	atomic_set(&adapter->contexts_num, -1);
 
+	return adapter;
 err2:
 	cxl_remove_adapter_nr(adapter);
 err1:
@@ -286,6 +288,44 @@ int cxl_afu_select_best_mode(struct cxl_afu *afu)
 	return 0;
 }
 
+int cxl_adapter_context_get(struct cxl *adapter)
+{
+	int rc;
+
+	rc = atomic_inc_unless_negative(&adapter->contexts_num);
+	return rc >= 0 ? 0 : -EBUSY;
+}
+
+void cxl_adapter_context_put(struct cxl *adapter)
+{
+	atomic_dec_if_positive(&adapter->contexts_num);
+}
+
+int cxl_adapter_context_lock(struct cxl *adapter)
+{
+	int rc;
+	/* no active contexts -> contexts_num == 0 */
+	rc = atomic_cmpxchg(&adapter->contexts_num, 0, -1);
+	return rc ? -EBUSY : 0;
+}
+
+void cxl_adapter_context_unlock(struct cxl *adapter)
+{
+	int val = atomic_cmpxchg(&adapter->contexts_num, -1, 0);
+
+	/*
+	 * contexts lock taken -> contexts_num == -1
+	 * If not true then show a warning and force reset the lock.
+	 * This will happen when context_unlock was requested without
+	 * doing a context_lock.
+	 */
+	if (val != -1) {
+		atomic_set(&adapter->contexts_num, 0);
+		WARN(1, "Adapter context unlocked with %d active contexts",
+		     val);
+	}
+}
+
 static int __init init_cxl(void)
 {
 	int rc = 0;