In order to use arbitrary block devices as a pstore backend, provide a
new module param named "best_effort", which will allow using any block
device, even if it has not provided a panic_write callback.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
fs/pstore/blk.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 0dea8ded2de2..ad46860d5a78 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -51,6 +51,10 @@ static long ftrace_size = -1;
module_param(ftrace_size, long, 0400);
MODULE_PARM_DESC(ftrace_size, "ftrace size in kbytes");
+static bool best_effort;
+module_param(best_effort, bool, 0400);
+MODULE_PARM_DESC(best_effort, "use best effort to write (i.e. do not require storage driver pstore support, default: off)");
+
/*
* blkdev - the block device to use for pstore storage
*
@@ -376,7 +380,8 @@ static int __register_pstore_blk(struct pstore_blk_info *info)
}
/* only allow driver matching the @blkdev */
- if (!binfo.devt || MAJOR(binfo.devt) != info->major) {
+ if (!binfo.devt || (!best_effort &&
+ MAJOR(binfo.devt) != info->major)) {
pr_debug("invalid major %u (expect %u)\n",
info->major, MAJOR(binfo.devt));
ret = -ENODEV;
@@ -479,6 +484,20 @@ int pstore_blk_get_config(struct pstore_blk_config *info)
}
EXPORT_SYMBOL_GPL(pstore_blk_get_config);
+static int __init pstore_blk_init(void)
+{
+ struct pstore_blk_info info = { };
+ int ret = 0;
+
+ mutex_lock(&pstore_blk_lock);
+ if (!pstore_zone_info && best_effort && blkdev[0])
+ ret = __register_pstore_blk(&info);
+ mutex_unlock(&pstore_blk_lock);
+
+ return ret;
+}
+late_initcall(pstore_blk_init);
+
static void __exit pstore_blk_exit(void)
{
mutex_lock(&pstore_blk_lock);
--
2.20.1
