UBIFS: pre-allocate bulk-read buffer

To avoid memory allocation failure during bulk-read, pre-allocate
a bulk-read buffer, so that if there is only one bulk-reader at
a time, it would just use the pre-allocated buffer and would not
do any memory allocation. However, if there are more than 1 bulk-
reader, then only one reader would use the pre-allocated buffer,
while the other reader would allocate the buffer for itself.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 870b5c479e95..46b172560a06 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -969,7 +969,10 @@ struct ubifs_mount_opts {
  * @mst_node: master node
  * @mst_offs: offset of valid master node
  * @mst_mutex: protects the master node area, @mst_node, and @mst_offs
+ *
  * @max_bu_buf_len: maximum bulk-read buffer length
+ * @bu_mutex: protects the pre-allocated bulk-read buffer and @c->bu
+ * @bu: pre-allocated bulk-read information
  *
  * @log_lebs: number of logical eraseblocks in the log
  * @log_bytes: log size in bytes
@@ -1217,7 +1220,10 @@ struct ubifs_info {
         struct ubifs_mst_node *mst_node;
         int mst_offs;
         struct mutex mst_mutex;
+
         int max_bu_buf_len;
+        struct mutex bu_mutex;
+        struct bu_info bu;
 
         int log_lebs;
         long long log_bytes;