diff options
| -rw-r--r-- | block/blk-mq.c | 6 | ||||
| -rw-r--r-- | block/blk.h | 7 |
2 files changed, 13 insertions, 0 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index a7b46b754a7c..076cbab9c3e0 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2923,6 +2923,12 @@ EXPORT_SYMBOL_GPL(blk_mq_poll); static int __init blk_mq_init(void) { + /* + * See comment in block/blk.h rq_atomic_flags enum + */ + BUILD_BUG_ON((REQ_ATOM_STARTED / BITS_PER_BYTE) != + (REQ_ATOM_COMPLETE / BITS_PER_BYTE)); + cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, blk_mq_hctx_notify_dead); return 0; diff --git a/block/blk.h b/block/blk.h index fda5a4632aba..6ac43dfd68a7 100644 --- a/block/blk.h +++ b/block/blk.h @@ -122,8 +122,15 @@ void blk_account_io_done(struct request *req); * Internal atomic flags for request handling */ enum rq_atomic_flags { + /* + * Keep these two bits first - not because we depend on the + * value of them, but we do depend on them being in the same + * byte of storage to ensure ordering on writes. Keeping them + * first will achieve that nicely. + */ REQ_ATOM_COMPLETE = 0, REQ_ATOM_STARTED, + REQ_ATOM_POLL_SLEPT, }; |