Add buffer head related helper function
bh_uptodate_or_lock and bh_submit_read
which can be used by file system
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
include/linux/buffer_head.h | 29 +++++++++++++++++++++++++++++
1 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index da0d83f..82cc9ef 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -327,6 +327,35 @@ static inline void lock_buffer(struct buffer_head *bh)
extern int __set_page_dirty_buffers(struct page *page);
+/* Return true if the buffer is up-to-date.
+ * Return false, with the buffer locked, if not.
+ */
+static inline int bh_uptodate_or_lock(struct buffer_head *bh)
+{
+ if (!buffer_uptodate(bh)) {
+ lock_buffer(bh);
+ if (!buffer_uptodate(bh))
+ return 0;
+ unlock_buffer(bh);
+ }
+ return 1;
+}
+/*
+ * Submit a locked buffer for reading,
+ * return a negative error and release
+ * the buffer if failed.
+ */
+static inline int bh_submit_read(struct buffer_head *bh)
+{
+ get_bh(bh);
+ bh->b_end_io = end_buffer_read_sync;
+ submit_bh(READ, bh);
+ wait_on_buffer(bh);
+ if (buffer_uptodate(bh))
+ return 0;
+ brelse(bh);
+ return -EIO;
+}
#else /* CONFIG_BLOCK */
static inline void buffer_init(void) {}
--
1.5.3.5.652.gf192c-dirty
-
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