pstore: Allow the user to explicitly choose a backend

pstore only allows one backend to be registered at present, but the
system may provide several. Add a parameter to allow the user to choose
which backend will be used rather than just relying on load order.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

2 files changed, 8 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.