configfs: consistent attribute size
The attribute store/show code currently limits attributes at PAGE_SIZE.
This code comes from sysfs, where it still works that way.
However, PAGE_SIZE is not constant. A 16k attribute string works on
ia64 but not on x86. Really a subsystem shouldn't allow different
attribute sizes based on platform.
As such, limit all simple attributes to 4k. This works on all
platforms, and is consistent with all current code.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index 3527c7c..0f4b65e 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -33,6 +33,13 @@
#include <linux/configfs.h>
#include "configfs_internal.h"
+/*
+ * A simple attribute can only be 4096 characters. Why 4k? Because the
+ * original code limited it to PAGE_SIZE. That's a bad idea, though,
+ * because an attribute of 16k on ia64 won't work on x86. So we limit to
+ * 4k, our minimum common page size.
+ */
+#define SIMPLE_ATTR_SIZE 4096
struct configfs_buffer {
size_t count;
@@ -69,7 +76,7 @@
count = ops->show_attribute(item,attr,buffer->page);
buffer->needs_read_fill = 0;
- BUG_ON(count > (ssize_t)PAGE_SIZE);
+ BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
if (count >= 0)
buffer->count = count;
else
@@ -137,8 +144,8 @@
if (!buffer->page)
return -ENOMEM;
- if (count >= PAGE_SIZE)
- count = PAGE_SIZE - 1;
+ if (count >= SIMPLE_ATTR_SIZE)
+ count = SIMPLE_ATTR_SIZE - 1;
error = copy_from_user(buffer->page,buf,count);
buffer->needs_read_fill = 1;
/* if buf is assumed to contain a string, terminate it by \0,