3 files changed, 19 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/pstore b/Documentation/ABI/testing/pstore
index ddf451ee2a08..ff1df4e3b059 100644
--- a/Documentation/ABI/testing/pstore
+++ b/Documentation/ABI/testing/pstore
@@ -39,3 +39,9 @@ Description:	Generic interface to platform dependent persistent storage.
                 multiple) files based on the record size of the underlying
                 persistent storage until at least this amount is reached.
                 Default is 10 Kbytes.
+
+                Pstore only supports one backend at a time. If multiple
+                backends are available, the preferred backend may be
+                set by passing the pstore.backend= argument to the kernel at
+                boot time.
+
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index aa47be71df4c..8789d0c9291a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2151,6 +2151,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         [HW,MOUSE] Controls Logitech smartscroll autorepeat.
                         0 = disabled, 1 = enabled (default).
 
+        pstore.backend= Specify the name of the pstore backend to use
+
         pt.             [PARIDE]
                         See Documentation/blockdev/paride.txt.
 
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 49ff1de2178a..c5300ec31696 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -37,6 +37,8 @@
 static DEFINE_SPINLOCK(pstore_lock);
 static struct pstore_info *psinfo;
 
+static char *backend;
+
 /* How much of the console log to snapshot */
 static unsigned long kmsg_bytes = 10240;
 
@@ -131,6 +133,12 @@ int pstore_register(struct pstore_info *psi)
                 spin_unlock(&pstore_lock);
                 return -EBUSY;
         }
+
+        if (backend && strcmp(backend, psi->name)) {
+                spin_unlock(&pstore_lock);
+                return -EINVAL;
+        }
+
         psinfo = psi;
         spin_unlock(&pstore_lock);
 
@@ -208,3 +216,6 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size)
         return 0;
 }
 EXPORT_SYMBOL_GPL(pstore_write);
+
+module_param(backend, charp, 0444);
+MODULE_PARM_DESC(backend, "Pstore backend to use");