The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=c5041b4ee8c3385cec03e6ccf73af78cadfe8d90
commit c5041b4ee8c3385cec03e6ccf73af78cadfe8d90 Author: Warner Losh <[email protected]> AuthorDate: 2022-04-28 17:13:58 +0000 Commit: Warner Losh <[email protected]> CommitDate: 2022-04-28 17:19:39 +0000 mpr/mps: Add comment explaining state transition When we can't load a request due to a shortage of chains, we complete the command's cm. However, to avoid an assert in mp?_complete_command, we transition its state to INQUEUE. This transition is legitimate because this is the only error path that terminates a cm before it's enqueued and the only other alternative would be an additional transient state that would add complexity w/o adding value. Add a comment explainging all this because otherwise the transition can look a bit weird. Sponsored by: Netflix --- sys/dev/mpr/mpr.c | 6 ++++++ sys/dev/mps/mps.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/sys/dev/mpr/mpr.c b/sys/dev/mpr/mpr.c index 0f4c5c906216..b4d3f3269dba 100644 --- a/sys/dev/mpr/mpr.c +++ b/sys/dev/mpr/mpr.c @@ -3704,6 +3704,12 @@ mpr_data_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error) mpr_dprint(sc, MPR_INFO, "Out of chain frames, " "consider increasing hw.mpr.max_chains.\n"); cm->cm_flags |= MPR_CM_FLAGS_CHAIN_FAILED; + /* + * mpr_complete_command can only be called on commands + * that are in the queue. Since this is an error path + * which gets called before we enqueue, update the state + * to meet this requirement before we complete it. + */ cm->cm_state = MPR_CM_STATE_INQUEUE; mpr_complete_command(sc, cm); return; diff --git a/sys/dev/mps/mps.c b/sys/dev/mps/mps.c index 5021acf930a3..b3f470bf5a39 100644 --- a/sys/dev/mps/mps.c +++ b/sys/dev/mps/mps.c @@ -2983,6 +2983,12 @@ mps_data_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error) mps_dprint(sc, MPS_INFO, "Out of chain frames, " "consider increasing hw.mps.max_chains.\n"); cm->cm_flags |= MPS_CM_FLAGS_CHAIN_FAILED; + /* + * mpr_complete_command can only be called on commands + * that are in the queue. Since this is an error path + * which gets called before we enqueue, update the state + * to meet this requirement before we complete it. + */ cm->cm_state = MPS_CM_STATE_INQUEUE; mps_complete_command(sc, cm); return;
