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

[Greg Kroah-Hartman]

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Cc: Rui Xiang <rui.xiang@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 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++)


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