git: b7e27af36b7d - main - safexcel: Handle command/result descriptor exhaustion gracefully

[Mark Johnston]

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=b7e27af36b7df05f4b6cdc706750413f3a048640

commit b7e27af36b7df05f4b6cdc706750413f3a048640
Author:     Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-01-18 22:07:56 +0000
Commit:     Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-01-18 22:07:56 +0000

    safexcel: Handle command/result descriptor exhaustion gracefully
    
    Rather than returning a hard error in this case, return ERESTART so that
    upper layers get a chance to retry the request (or drop it, depending on
    the desired policy).
    
    This case is hard to hit due to the somewhat low bound on queued
    requests, but that will no longer be true after an upcoming change.
    
    MFC after:      1 week
    Sponsored by:   Rubicon Communications, LLC (Netgate)
---
 sys/dev/safexcel/safexcel.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/sys/dev/safexcel/safexcel.c b/sys/dev/safexcel/safexcel.c
index c30b8178efb1..2f0f10f1d5e8 100644
--- a/sys/dev/safexcel/safexcel.c
+++ b/sys/dev/safexcel/safexcel.c
@@ -2093,7 +2093,7 @@ safexcel_create_chain_cb(void *arg, bus_dma_segment_t *segs, int nseg,
 		if (cdesc == NULL) {
 			safexcel_cmd_descr_rollback(ring, i);
 			counter_u64_add(req->sc->sc_cdesc_alloc_failures, 1);
-			req->error = EAGAIN;
+			req->error = ERESTART;
 			return;
 		}
 		if (i == 0)
@@ -2121,7 +2121,7 @@ safexcel_create_chain_cb(void *arg, bus_dma_segment_t *segs, int nseg,
 			    ring->cmd_data->sg_nseg);
 			safexcel_res_descr_rollback(ring, i);
 			counter_u64_add(req->sc->sc_rdesc_alloc_failures, 1);
-			req->error = EAGAIN;
+			req->error = ERESTART;
 			return;
 		}
 	}
@@ -2608,10 +2608,16 @@ safexcel_process(device_t dev, struct cryptop *crp, int hint)
 	error = safexcel_create_chain(ring, req);
 	if (__predict_false(error != 0)) {
 		safexcel_free_request(ring, req);
+		if (error == ERESTART)
+			ring->blocked = CRYPTO_SYMQ;
 		mtx_unlock(&ring->mtx);
-		crp->crp_etype = error;
-		crypto_done(crp);
-		return (0);
+		if (error != ERESTART) {
+			crp->crp_etype = error;
+			crypto_done(crp);
+			return (0);
+		} else {
+			return (ERESTART);
+		}
 	}
 
 	safexcel_set_token(req);