[PATCH 5/6] blk-mq: Add blk_mq_ops.show_rq()

Bart Van Assche
2017-04-11T20:58:41Z

This new callback function will be used in the next patch to show
more information about SCSI requests.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Hannes Reinecke <hare@suse.com>
---
block/blk-mq-debugfs.c | 10 ++++++++--
include/linux/blk-mq.h | 6 ++++++
2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 161f30fc236f..6b28d92d4c0e 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -316,7 +316,9 @@ static const char *const rqf_name[] = {
static int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
{
struct request *rq = list_entry_rq(v);
+ const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
+ char drv_info[200];

seq_printf(m, "%p {.op=", rq);
if (op < ARRAY_SIZE(op_name) && op_name[op])
@@ -329,8 +331,12 @@ static int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
seq_puts(m, ", .rq_flags=");
blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
ARRAY_SIZE(rqf_name));
- seq_printf(m, ", .tag=%d, .internal_tag=%d}\n", rq->tag,
- rq->internal_tag);
+ if (mq_ops->show_rq)
+ mq_ops->show_rq(rq, drv_info, sizeof(drv_info));
+ else
+ drv_info[0] = '\0';
+ seq_printf(m, ", .tag=%d, .internal_tag=%d%s%s}\n", rq->tag,
+ rq->internal_tag, drv_info[0] ? ", " : "", drv_info);
return 0;
}

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index dea255dee359..de2a1c2ddd84 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -120,6 +120,12 @@ struct blk_mq_ops {
softirq_done_fn *complete;

/*
+ * Used by the debugfs implementation to show driver-specific
+ * information about a request.
+ */
+ void (*show_rq)(struct request *rq, char *info, unsigned int info_sz);
+
+ /*
* Called when the block layer side of a hardware queue has been
* set up, allowing the driver to allocate/init matching structures.
* Ditto for exit/teardown.
--
2.12.0