soc: qcom: glink: Reduce code under spinlock

Glink core channel cleanup has a lot of code under spinlock with
preemption disabled this leads to deadlock scenerio.

Spinklock is used only for critical section, rest of the code is
be without spinlock.

CRs-Fixed: 1060407
Change-Id: I577dbff1cf2ee3711e1879aaa6dc48c72f98b98c
Signed-off-by: Dhoat Harpal <hdhoat@codeaurora.org>

1 files changed, 39 insertions, 20 deletions

diff --git a/drivers/soc/qcom/glink.c b/drivers/soc/qcom/glink.c
index 57e58a57fab7..323990a89e4d 100644
--- a/drivers/soc/qcom/glink.c
+++ b/drivers/soc/qcom/glink.c
@@ -4020,6 +4020,37 @@ static struct glink_core_xprt_ctx *glink_create_dummy_xprt_ctx(
 	return xprt_ptr;
 }
 
+static struct channel_ctx *get_first_ch_ctx(
+	struct glink_core_xprt_ctx *xprt_ctx)
+{
+	unsigned long flags;
+	struct channel_ctx *ctx;
+
+	spin_lock_irqsave(&xprt_ctx->xprt_ctx_lock_lhb1, flags);
+	if (!list_empty(&xprt_ctx->channels)) {
+		ctx = list_first_entry(&xprt_ctx->channels,
+					struct channel_ctx, port_list_node);
+		rwref_get(&ctx->ch_state_lhb2);
+	} else {
+		ctx = NULL;
+	}
+	spin_unlock_irqrestore(&xprt_ctx->xprt_ctx_lock_lhb1, flags);
+	return ctx;
+}
+
+static void glink_core_move_ch_node(struct glink_core_xprt_ctx *xprt_ptr,
+	struct glink_core_xprt_ctx *dummy_xprt_ctx, struct channel_ctx *ctx)
+{
+	unsigned long flags, d_flags;
+
+	spin_lock_irqsave(&dummy_xprt_ctx->xprt_ctx_lock_lhb1, d_flags);
+	spin_lock_irqsave(&xprt_ptr->xprt_ctx_lock_lhb1, flags);
+	rwref_get(&dummy_xprt_ctx->xprt_state_lhb0);
+	list_move_tail(&ctx->port_list_node, &dummy_xprt_ctx->channels);
+	spin_unlock_irqrestore(&xprt_ptr->xprt_ctx_lock_lhb1, flags);
+	spin_unlock_irqrestore(&dummy_xprt_ctx->xprt_ctx_lock_lhb1, d_flags);
+}
+
 /**
  * glink_core_channel_cleanup() - cleanup all channels for the transport
  *
@@ -4030,7 +4061,7 @@ static struct glink_core_xprt_ctx *glink_create_dummy_xprt_ctx(
 static void glink_core_channel_cleanup(struct glink_core_xprt_ctx *xprt_ptr)
 {
 	unsigned long flags, d_flags;
-	struct channel_ctx *ctx, *tmp_ctx;
+	struct channel_ctx *ctx;
 	struct channel_lcid *temp_lcid, *temp_lcid1;
 	struct glink_core_xprt_ctx *dummy_xprt_ctx;
 
@@ -4039,29 +4070,18 @@ static void glink_core_channel_cleanup(struct glink_core_xprt_ctx *xprt_ptr)
 		GLINK_ERR("%s: Dummy Transport creation failed\n", __func__);
 		return;
 	}
-
 	rwref_read_get(&dummy_xprt_ctx->xprt_state_lhb0);
 	rwref_read_get(&xprt_ptr->xprt_state_lhb0);
-	spin_lock_irqsave(&dummy_xprt_ctx->xprt_ctx_lock_lhb1, d_flags);
-	spin_lock_irqsave(&xprt_ptr->xprt_ctx_lock_lhb1, flags);
-
-	list_for_each_entry_safe(ctx, tmp_ctx, &xprt_ptr->channels,
-						port_list_node) {
+	ctx = get_first_ch_ctx(xprt_ptr);
+	while (ctx) {
 		rwref_write_get_atomic(&ctx->ch_state_lhb2, true);
 		if (ctx->local_open_state == GLINK_CHANNEL_OPENED ||
 			ctx->local_open_state == GLINK_CHANNEL_OPENING) {
-			rwref_get(&dummy_xprt_ctx->xprt_state_lhb0);
-			list_move_tail(&ctx->port_list_node,
-					&dummy_xprt_ctx->channels);
 			ctx->transport_ptr = dummy_xprt_ctx;
 			rwref_write_put(&ctx->ch_state_lhb2);
+			glink_core_move_ch_node(xprt_ptr, dummy_xprt_ctx, ctx);
 		} else {
 			/* local state is in either CLOSED or CLOSING */
-			spin_unlock_irqrestore(&xprt_ptr->xprt_ctx_lock_lhb1,
-							flags);
-			spin_unlock_irqrestore(
-					&dummy_xprt_ctx->xprt_ctx_lock_lhb1,
-					d_flags);
 			glink_core_remote_close_common(ctx, true);
 			if (ctx->local_open_state == GLINK_CHANNEL_CLOSING)
 				glink_core_ch_close_ack_common(ctx, true);
@@ -4069,22 +4089,21 @@ static void glink_core_channel_cleanup(struct glink_core_xprt_ctx *xprt_ptr)
 			if (ch_is_fully_closed(ctx))
 				glink_delete_ch_from_list(ctx, false);
 			rwref_write_put(&ctx->ch_state_lhb2);
-			spin_lock_irqsave(&dummy_xprt_ctx->xprt_ctx_lock_lhb1,
-						d_flags);
-			spin_lock_irqsave(&xprt_ptr->xprt_ctx_lock_lhb1, flags);
 		}
+		rwref_put(&ctx->ch_state_lhb2);
+		ctx = get_first_ch_ctx(xprt_ptr);
 	}
+	spin_lock_irqsave(&xprt_ptr->xprt_ctx_lock_lhb1, flags);
 	list_for_each_entry_safe(temp_lcid, temp_lcid1,
 			&xprt_ptr->free_lcid_list, list_node) {
 		list_del(&temp_lcid->list_node);
 		kfree(&temp_lcid->list_node);
 	}
-	dummy_xprt_ctx->dummy_in_use = false;
 	spin_unlock_irqrestore(&xprt_ptr->xprt_ctx_lock_lhb1, flags);
-	spin_unlock_irqrestore(&dummy_xprt_ctx->xprt_ctx_lock_lhb1, d_flags);
 	rwref_read_put(&xprt_ptr->xprt_state_lhb0);
 
 	spin_lock_irqsave(&dummy_xprt_ctx->xprt_ctx_lock_lhb1, d_flags);
+	dummy_xprt_ctx->dummy_in_use = false;
 	while (!list_empty(&dummy_xprt_ctx->channels)) {
 		ctx = list_first_entry(&dummy_xprt_ctx->channels,
 					struct channel_ctx, port_list_node);