pstore: use mount option instead sysfs to tweak kmsg_bytes

/sys/fs is a somewhat strange way to tweak what could more
obviously be tuned with a mount option.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 705fdf8..ce9ad84 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -37,24 +37,14 @@
 static DEFINE_SPINLOCK(pstore_lock);
 static struct pstore_info *psinfo;
 
-/* How much of the console log to snapshot. /sys/fs/pstore/kmsg_bytes */
+/* How much of the console log to snapshot */
 static unsigned long kmsg_bytes = 10240;
 
-static ssize_t b_show(struct kobject *kobj,
-		      struct kobj_attribute *attr, char *buf)
+void pstore_set_kmsg_bytes(int bytes)
 {
-	return snprintf(buf, PAGE_SIZE, "%lu\n", kmsg_bytes);
+	kmsg_bytes = bytes;
 }
 
-static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr,
-		       const char *buf, size_t count)
-{
-	return (sscanf(buf, "%lu", &kmsg_bytes) > 0) ? count : 0;
-}
-
-struct kobj_attribute pstore_kmsg_bytes_attr =
-	__ATTR(kmsg_bytes, S_IRUGO | S_IWUSR, b_show, b_store);
-
 /* Tag each group of saved records with a sequence number */
 static int	oopscount;