soc: qcom: hab: refine hab virtual channel's resource free

Whenever a vchan is locally closed in hab_vchan_close or hab_free,
4 actions should be taken immediately, including,
 - remove it from the local hab context
 - mark its local closed flag
 - notify remote side and unblock local blocking calls over it
 - decrease the refcnt on the vchan

Change-Id: I3fbde9464f6405b6dadac248768a5fd857a29128
Signed-off-by: Yong Ding <yongding@codeaurora.org>

2 files changed, 17 insertions, 56 deletions

diff --git a/drivers/soc/qcom/hab/hab.c b/drivers/soc/qcom/hab/hab.c
index 7d53e6162172..24461d2c957b 100644
--- a/drivers/soc/qcom/hab/hab.c
+++ b/drivers/soc/qcom/hab/hab.c
@@ -720,11 +720,18 @@ void hab_vchan_close(struct uhab_context *ctx, int32_t vcid)
 	write_lock(&ctx->ctx_lock);
 	list_for_each_entry_safe(vchan, tmp, &ctx->vchannels, node) {
 		if (vchan->id == vcid) {
+			/* local close starts */
 			vchan->closed = 1;
-			write_unlock(&ctx->ctx_lock);
+
+			/* vchan is not in this ctx anymore */
+			list_del(&vchan->node);
+			ctx->vcnt--;
+
 			pr_debug("vcid %x remote %x session %d refcnt %d\n",
 				vchan->id, vchan->otherend_id,
 				vchan->session_id, get_refcnt(vchan->refcount));
+
+			write_unlock(&ctx->ctx_lock);
 			/* unblocking blocked in-calls */
 			hab_vchan_stop_notify(vchan);
 			hab_vchan_put(vchan); /* there is a lock inside */
@@ -1069,28 +1076,14 @@ static int hab_release(struct inode *inodep, struct file *filep)
 	write_lock(&ctx->ctx_lock);
 	/* notify remote side on vchan closing */
 	list_for_each_entry_safe(vchan, tmp, &ctx->vchannels, node) {
-		list_del(&vchan->node); /* vchan is not in this ctx anymore */
+		/* local close starts */
+		vchan->closed = 1;
 
-		if (!vchan->closed) { /* locally hasn't closed yet */
-			if (!kref_get_unless_zero(&vchan->refcount)) {
-				pr_err("vchan %x %x refcnt %d mismanaged closed %d remote closed %d\n",
-					vchan->id,
-					vchan->otherend_id,
-					get_refcnt(vchan->refcount),
-					vchan->closed, vchan->otherend_closed);
-				continue; /* vchan is already being freed */
-			} else {
-				write_unlock(&ctx->ctx_lock);
-				hab_vchan_stop_notify(vchan);
-				/* put for notify. shouldn't cause free */
-				hab_vchan_put(vchan);
-				write_lock(&ctx->ctx_lock);
-			}
-		} else
-			continue;
+		list_del(&vchan->node); /* vchan is not in this ctx anymore */
+		ctx->vcnt--;
 
-		/* for the missing local vchan close */
 		write_unlock(&ctx->ctx_lock);
+		hab_vchan_stop_notify(vchan);
 		hab_vchan_put(vchan); /* there is a lock inside */
 		write_lock(&ctx->ctx_lock);
 	}
diff --git a/drivers/soc/qcom/hab/hab_vchan.c b/drivers/soc/qcom/hab/hab_vchan.c
index 770c6ba3dadd..a95d6c7451c9 100644
--- a/drivers/soc/qcom/hab/hab_vchan.c
+++ b/drivers/soc/qcom/hab/hab_vchan.c
@@ -85,9 +85,6 @@ hab_vchan_free(struct kref *ref)
 	}
 	spin_unlock_bh(&vchan->rx_lock);
 
-	/* the release vchan from ctx was done earlier in vchan close() */
-	hab_ctx_put(ctx); /* now ctx is not needed from this vchan's view */
-
 	/* release vchan from pchan. no more msg for this vchan */
 	write_lock_bh(&pchan->vchans_lock);
 	list_for_each_entry_safe(vc, vc_tmp, &pchan->vchannels, pnode) {
@@ -100,6 +97,9 @@ hab_vchan_free(struct kref *ref)
 	}
 	write_unlock_bh(&pchan->vchans_lock);
 
+	/* the release vchan from ctx was done earlier in vchan close() */
+	hab_ctx_put(ctx); /* now ctx is not needed from this vchan's view */
+
 	/* release idr at the last so same idr will not be used early */
 	spin_lock_bh(&pchan->vid_lock);
 	idr_remove(&pchan->vchan_idr, HAB_VCID_GET_ID(vchan->id));
@@ -274,42 +274,10 @@ int hab_vchan_find_domid(struct virtual_channel *vchan)
 	return vchan ? vchan->pchan->dom_id : -1;
 }
 
-/* this sould be only called once after refcnt is zero */
-static void hab_vchan_schedule_free(struct kref *ref)
-{
-	struct virtual_channel *vchanin =
-		container_of(ref, struct virtual_channel, refcount);
-	struct uhab_context *ctx = vchanin->ctx;
-	struct virtual_channel *vchan, *tmp;
-	int bnotify = 0;
-
-	/*
-	 * similar logic is in ctx free. if ctx free runs first,
-	 * this is skipped
-	 */
-	write_lock_bh(&ctx->ctx_lock);
-	list_for_each_entry_safe(vchan, tmp, &ctx->vchannels, node) {
-		if (vchan == vchanin) {
-			pr_debug("vchan free refcnt = %d\n",
-					 get_refcnt(vchan->refcount));
-			ctx->vcnt--;
-			list_del(&vchan->node);
-			bnotify = 1;
-			break;
-		}
-	}
-	write_unlock_bh(&ctx->ctx_lock);
-
-	if (bnotify)
-		hab_vchan_stop_notify(vchan);
-
-	hab_vchan_free(ref);
-}
-
 void hab_vchan_put(struct virtual_channel *vchan)
 {
 	if (vchan)
-		kref_put(&vchan->refcount, hab_vchan_schedule_free);
+		kref_put(&vchan->refcount, hab_vchan_free);
 }
 
 int hab_vchan_query(struct uhab_context *ctx, int32_t vcid, uint64_t *ids,