From 79a4dcc4e502d9ac54d3dfa30d75bd63c66edc60 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Sat, 13 Nov 2010 14:38:44 +0000
Subject: [PATCH] ib_srpt: Made sure that no credits are lost because of SCSI
 task abortion. ib_srpt: Exported req_lim and req_lim_delta values via sysfs
 because this is convenient for debugging purposes.

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@2686 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 srpt/src/ib_srpt.c | 53 +++++++++++++++++++++++++++++++++++++++++++---
 srpt/src/ib_srpt.h |  1 +
 2 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/srpt/src/ib_srpt.c b/srpt/src/ib_srpt.c
index f9c122543..389f13506 100644
--- a/srpt/src/ib_srpt.c
+++ b/srpt/src/ib_srpt.c
@@ -1407,7 +1407,8 @@ static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
 	memset(srp_rsp, 0, sizeof *srp_rsp);
 
 	srp_rsp->opcode = SRP_RSP;
-	srp_rsp->req_lim_delta = __constant_cpu_to_be32(1);
+	srp_rsp->req_lim_delta = __constant_cpu_to_be32(1
+				    + atomic_xchg(&ch->req_lim_delta, 0));
 	srp_rsp->tag = tag;
 	srp_rsp->status = status;
 
@@ -1459,7 +1460,8 @@ static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
 	memset(srp_rsp, 0, sizeof *srp_rsp);
 
 	srp_rsp->opcode = SRP_RSP;
-	srp_rsp->req_lim_delta = __constant_cpu_to_be32(1);
+	srp_rsp->req_lim_delta = __constant_cpu_to_be32(1
+				    + atomic_xchg(&ch->req_lim_delta, 0));
 	srp_rsp->tag = tag;
 
 	if (rsp_code != SRP_TSK_MGMT_SUCCESS) {
@@ -2417,6 +2419,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
 					      | SRP_BUF_FORMAT_INDIRECT);
 	rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
 	atomic_set(&ch->req_lim, ch->rq_size);
+	atomic_set(&ch->req_lim_delta, 0);
 
 	/* create cm reply */
 	rep_param->qp_num = ch->qp->qp_num;
@@ -3411,6 +3414,48 @@ static ssize_t show_login_info(struct device *dev,
 	return len;
 }
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+static ssize_t show_req_lim(struct class_device *dev, char *buf)
+#else
+static ssize_t show_req_lim(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+#endif
+{
+	struct srpt_device *sdev;
+	struct srpt_rdma_ch *ch;
+	int req_lim;
+
+	sdev = container_of(dev, struct srpt_device, dev);
+	req_lim = 0;
+	spin_lock_irq(&sdev->spinlock);
+	list_for_each_entry(ch, &sdev->rch_list, list)
+		req_lim += atomic_read(&ch->req_lim);
+	spin_unlock_irq(&sdev->spinlock);
+
+	return sprintf(buf, "%d\n", req_lim);
+}
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+static ssize_t show_req_lim_delta(struct class_device *dev, char *buf)
+#else
+static ssize_t show_req_lim_delta(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+#endif
+{
+	struct srpt_device *sdev;
+	struct srpt_rdma_ch *ch;
+	int req_lim_delta;
+
+	sdev = container_of(dev, struct srpt_device, dev);
+	req_lim_delta = 0;
+	spin_lock_irq(&sdev->spinlock);
+	list_for_each_entry(ch, &sdev->rch_list, list)
+		req_lim_delta += atomic_read(&ch->req_lim_delta);
+	spin_unlock_irq(&sdev->spinlock);
+
+	return sprintf(buf, "%d\n", req_lim_delta);
+}
+
 static struct class_attribute srpt_class_attrs[] = {
 	__ATTR_NULL,
 };
@@ -3420,7 +3465,9 @@ static struct class_device_attribute srpt_dev_attrs[] = {
 #else
 static struct device_attribute srpt_dev_attrs[] = {
 #endif
-	__ATTR(login_info, S_IRUGO, show_login_info, NULL),
+	__ATTR(login_info,    S_IRUGO, show_login_info,    NULL),
+	__ATTR(req_lim,       S_IRUGO, show_req_lim,       NULL),
+	__ATTR(req_lim_delta, S_IRUGO, show_req_lim_delta, NULL),
 	__ATTR_NULL,
 };
 
diff --git a/srpt/src/ib_srpt.h b/srpt/src/ib_srpt.h
index c3d920c82..4f23dd0fd 100644
--- a/srpt/src/ib_srpt.h
+++ b/srpt/src/ib_srpt.h
@@ -278,6 +278,7 @@ struct srpt_rdma_ch {
 	u8			t_port_id[16];
 	int			max_ti_iu_len;
 	atomic_t		req_lim;
+	atomic_t		req_lim_delta;
 	spinlock_t		spinlock;
 	struct list_head	free_list;
 	struct srpt_send_ioctx	**ioctx_ring;