[PATCH v2 01/20] block: Add a flag for internal commands

Bart Van Assche
2021-11-19T19:57:57Z

From: Hannes Reinecke <hare@suse.de>

Some drivers use a single tag space for requests submitted by the block
layer and driver-internal requests. Driver-internal requests will never
pass through the block layer but require a valid tag. This patch adds a
new request flag REQ_INTERNAL to mark such requests and a terminates any
such commands in blk_execute_rq_nowait() with a WARN_ON_ONCE() to signal
such an invalid usage.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
[ bvanassche: modified patch description ]
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
block/blk-exec.c | 5 +++++
include/linux/blk-mq.h | 5 +++++
include/linux/blk_types.h | 2 ++
3 files changed, 12 insertions(+)

diff --git a/block/blk-exec.c b/block/blk-exec.c
index 1b8b47f6e79b..27d2e3779c13 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -53,6 +53,11 @@ void blk_execute_rq_nowait(struct gendisk *bd_disk, struct request *rq,
rq->rq_disk = bd_disk;
rq->end_io = done;

+ if (WARN_ON_ONCE(blk_rq_is_internal(rq))) {
+ blk_mq_end_request(rq, BLK_STS_NOTSUPP);
+ return;
+ }
+
blk_account_io_start(rq);

/*
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 2949d9ac7484..3b42fcdf0c15 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -208,6 +208,11 @@ static inline bool blk_rq_is_passthrough(struct request *rq)
return blk_op_is_passthrough(req_op(rq));
}

+static inline bool blk_rq_is_internal(struct request *rq)
+{
+ return rq->cmd_flags & REQ_INTERNAL;
+}
+
static inline unsigned short req_get_ioprio(struct request *req)
{
return req->ioprio;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index fe065c394fff..1ae2365e02d1 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -411,6 +411,7 @@ enum req_flag_bits {
/* for driver use */
__REQ_DRV,
__REQ_SWAP, /* swapping request. */
+ __REQ_INTERNAL, /* driver-internal command */
__REQ_NR_BITS, /* stops here */
};

@@ -435,6 +436,7 @@ enum req_flag_bits {

#define REQ_DRV (1ULL << __REQ_DRV)
#define REQ_SWAP (1ULL << __REQ_SWAP)
+#define REQ_INTERNAL (1ULL << __REQ_INTERNAL)

#define REQ_FAILFAST_MASK \
(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)