[V4,2/5] block: add centralize REQ_OP_XXX to string helper

Commit Message

Chaitanya Kulkarni June 19, 2019, 5:12 p.m. UTC

In order to centralize the REQ_OP_XXX to string conversion which can be
used in the block layer and different places in the kernel like f2fs,
this patch adds a new helper function along with an array similar to the
one present in the blk-mq-debugfs.c.

We keep this helper functionality centralize under blk-core.c instead of
blk-mq-debugfs.c since blk-core.c is configured using CONFIG_BLOCK and
it will not be dependent on blk-mq-debugfs.c which is configured using
CONFIG_BLK_DEBUG_FS.

Next patch adjusts the code in the blk-mq-debugfs.c with newly
introduced helper.

Signed-off-by: Chaitanya Kulkarni <[e-mail]>
---
 block/blk-core.c       | 36 ++++++++++++++++++++++++++++++++++++
 include/linux/blkdev.h |  3 +++
 2 files changed, 39 insertions(+)

Comments

Bart Van Assche June 19, 2019, 5:49 p.m. UTC | #1

On 6/19/19 10:12 AM, Chaitanya Kulkarni wrote:
> In order to centralize the REQ_OP_XXX to string conversion which can be
> used in the block layer and different places in the kernel like f2fs,
> this patch adds a new helper function along with an array similar to the
> one present in the blk-mq-debugfs.c.
> 
> We keep this helper functionality centralize under blk-core.c instead of
> blk-mq-debugfs.c since blk-core.c is configured using CONFIG_BLOCK and
> it will not be dependent on blk-mq-debugfs.c which is configured using
> CONFIG_BLK_DEBUG_FS.
> 
> Next patch adjusts the code in the blk-mq-debugfs.c with newly
> introduced helper.

Reviewed-by: Bart Van Assche <[e-mail]>

Patch

diff --git a/block/blk-core.c b/block/blk-core.c
index 6753231b529b..c92b5a16a27a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -120,6 +120,42 @@  void blk_rq_init(struct request_queue *q, struct request *rq)
 }
 EXPORT_SYMBOL(blk_rq_init);
 
+#define REQ_OP_NAME(name) [REQ_OP_##name] = #name
+static const char *const blk_op_name[] = {
+	REQ_OP_NAME(READ),
+	REQ_OP_NAME(WRITE),
+	REQ_OP_NAME(FLUSH),
+	REQ_OP_NAME(DISCARD),
+	REQ_OP_NAME(SECURE_ERASE),
+	REQ_OP_NAME(ZONE_RESET),
+	REQ_OP_NAME(WRITE_SAME),
+	REQ_OP_NAME(WRITE_ZEROES),
+	REQ_OP_NAME(SCSI_IN),
+	REQ_OP_NAME(SCSI_OUT),
+	REQ_OP_NAME(DRV_IN),
+	REQ_OP_NAME(DRV_OUT),
+};
+#undef REQ_OP_NAME
+
+/**
+ * blk_op_str - Return string XXX in the REQ_OP_XXX.
+ * @op: REQ_OP_XXX.
+ *
+ * Description: Centralize block layer function to convert REQ_OP_XXX into
+ * string format. Useful in the debugging and tracing bio or request. For
+ * invalid REQ_OP_XXX it returns string "UNKNOWN".
+ */
+inline const char *blk_op_str(unsigned int op)
+{
+	const char *op_str = "UNKNOWN";
+
+	if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
+		op_str = blk_op_name[op];
+
+	return op_str;
+}
+EXPORT_SYMBOL_GPL(blk_op_str);
+
 static const struct {
 	int		errno;
 	const char	*name;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 592669bcc536..077a77a4a91c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -867,6 +867,9 @@  extern void blk_execute_rq(struct request_queue *, struct gendisk *,
 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 				  struct request *, int, rq_end_io_fn *);
 
+/* Helper to convert REQ_OP_XXX to its string format XXX */
+extern const char *blk_op_str(unsigned int op);
+
 int blk_status_to_errno(blk_status_t status);
 blk_status_t errno_to_blk_status(int errno);