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>
diff --git a/Documentation/ABI/testing/pstore b/Documentation/ABI/testing/pstore
index ddf451e..ff1df4e 100644
--- a/Documentation/ABI/testing/pstore
+++ b/Documentation/ABI/testing/pstore
@@ -39,3 +39,9 @@
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 aa47be7..8789d0c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2151,6 +2151,8 @@
[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 49ff1de..c5300ec 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 @@
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 @@
return 0;
}
EXPORT_SYMBOL_GPL(pstore_write);
+
+module_param(backend, charp, 0444);
+MODULE_PARM_DESC(backend, "Pstore backend to use");