[PATCH 3.4 145/214] efivars: pstore: Do not check size when erasing variable

Greg Kroah-Hartman
2014-06-05T04:42:04Z

From: Ben Hutchings <ben@decadent.org.uk>

commit 80a19debc2f2d398cfa57fae97bc99826748a602 upstream.

In 3.2, unlike mainline, efi_pstore_erase() calls efi_pstore_write()
with a size of 0, as the underlying EFI interface treats a size of 0
as meaning deletion.

This was not taken into account in my backport of commit d80a361d779a
'efi_pstore: Check remaining space with QueryVariableInfo() before
writing data'. The size check should be omitted when erasing.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/firmware/efivars.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -778,19 +778,21 @@ static int efi_pstore_write(enum pstore_

spin_lock_irqsave(&efivars->lock, flags);

- /*
- * Check if there is a space enough to log.
- * size: a size of logging data
- * DUMP_NAME_LEN * 2: a maximum size of variable name
- */
+ if (size) {
+ /*
+ * Check if there is a space enough to log.
+ * size: a size of logging data
+ * DUMP_NAME_LEN * 2: a maximum size of variable name
+ */

- status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
- size + DUMP_NAME_LEN * 2);
+ status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
+ size + DUMP_NAME_LEN * 2);

- if (status) {
- spin_unlock_irqrestore(&efivars->lock, flags);
- *id = part;
- return -ENOSPC;
+ if (status) {
+ spin_unlock_irqrestore(&efivars->lock, flags);
+ *id = part;
+ return -ENOSPC;
+ }
}

for (i = 0; i < DUMP_NAME_LEN; i++)