[SCSI] bnx2fc: common free list for cleanup commands

Cleanup commands are issued to the firmware to cleanup any stuck ios
that are supposed to be implicitly aborted. In the worst case we can
have all scsi ios filling up the free_list and we may not be able to
allocate cleanup tasks. So the driver has to reserve free_list entries
to be able to allocate the cleanup tasks. This reserve free_list common
to all cpus is allocated as one additional entry in the per cpu
free_lists.

In bnx2fc_cmd_alloc(), there is a related fix to use get_cpu() for the
free_list_index.  This will prevent using the wrong index if the CPU
is preempted.

Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: Nithin Nayak Sujir <nsujir@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 48 insertions, 25 deletions

diff --git a/drivers/scsi/bnx2fc/bnx2fc_io.c b/drivers/scsi/bnx2fc/bnx2fc_io.c
index 0f1dd23..d3fc302 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_io.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_io.c
@@ -11,6 +11,9 @@
  */
 
 #include "bnx2fc.h"
+
+#define RESERVE_FREE_LIST_INDEX num_possible_cpus()
+
 static int bnx2fc_split_bd(struct bnx2fc_cmd *io_req, u64 addr, int sg_len,
 			   int bd_index);
 static int bnx2fc_map_sg(struct bnx2fc_cmd *io_req);
@@ -242,8 +245,9 @@ struct bnx2fc_cmd_mgr *bnx2fc_cmd_mgr_alloc(struct bnx2fc_hba *hba,
 	u32 mem_size;
 	u16 xid;
 	int i;
-	int num_ios;
+	int num_ios, num_pri_ios;
 	size_t bd_tbl_sz;
+	int arr_sz = num_possible_cpus() + 1;
 
 	if (max_xid <= min_xid || max_xid == FC_XID_UNKNOWN) {
 		printk(KERN_ERR PFX "cmd_mgr_alloc: Invalid min_xid 0x%x \
@@ -263,14 +267,14 @@ struct bnx2fc_cmd_mgr *bnx2fc_cmd_mgr_alloc(struct bnx2fc_hba *hba,
 	}
 
 	cmgr->free_list = kzalloc(sizeof(*cmgr->free_list) *
-				  num_possible_cpus(), GFP_KERNEL);
+				  arr_sz, GFP_KERNEL);
 	if (!cmgr->free_list) {
 		printk(KERN_ERR PFX "failed to alloc free_list\n");
 		goto mem_err;
 	}
 
 	cmgr->free_list_lock = kzalloc(sizeof(*cmgr->free_list_lock) *
-				       num_possible_cpus(), GFP_KERNEL);
+				       arr_sz, GFP_KERNEL);
 	if (!cmgr->free_list_lock) {
 		printk(KERN_ERR PFX "failed to alloc free_list_lock\n");
 		goto mem_err;
@@ -279,13 +283,18 @@ struct bnx2fc_cmd_mgr *bnx2fc_cmd_mgr_alloc(struct bnx2fc_hba *hba,
 	cmgr->hba = hba;
 	cmgr->cmds = (struct bnx2fc_cmd **)(cmgr + 1);
 
-	for (i = 0; i < num_possible_cpus(); i++)  {
+	for (i = 0; i < arr_sz; i++)  {
 		INIT_LIST_HEAD(&cmgr->free_list[i]);
 		spin_lock_init(&cmgr->free_list_lock[i]);
 	}
 
-	/* Pre-allocated pool of bnx2fc_cmds */
+	/*
+	 * Pre-allocated pool of bnx2fc_cmds.
+	 * Last entry in the free list array is the free list
+	 * of slow path requests.
+	 */
 	xid = BNX2FC_MIN_XID;
+	num_pri_ios = num_ios - BNX2FC_ELSTM_XIDS;
 	for (i = 0; i < num_ios; i++) {
 		io_req = kzalloc(sizeof(*io_req), GFP_KERNEL);
 
@@ -298,11 +307,13 @@ struct bnx2fc_cmd_mgr *bnx2fc_cmd_mgr_alloc(struct bnx2fc_hba *hba,
 		INIT_DELAYED_WORK(&io_req->timeout_work, bnx2fc_cmd_timeout);
 
 		io_req->xid = xid++;
-		if (io_req->xid >= BNX2FC_MAX_OUTSTANDING_CMNDS)
-			printk(KERN_ERR PFX "ERROR allocating xids - 0x%x\n",
-				io_req->xid);
-		list_add_tail(&io_req->link,
-			&cmgr->free_list[io_req->xid % num_possible_cpus()]);
+		if (i < num_pri_ios)
+			list_add_tail(&io_req->link,
+				&cmgr->free_list[io_req->xid %
+						 num_possible_cpus()]);
+		else
+			list_add_tail(&io_req->link,
+				&cmgr->free_list[num_possible_cpus()]);
 		io_req++;
 	}
 
@@ -389,7 +400,7 @@ free_cmd_pool:
 	if (!cmgr->free_list)
 		goto free_cmgr;
 
-	for (i = 0; i < num_possible_cpus(); i++)  {
+	for (i = 0; i < num_possible_cpus() + 1; i++)  {
 		struct list_head *list;
 		struct list_head *tmp;
 
@@ -413,6 +424,7 @@ struct bnx2fc_cmd *bnx2fc_elstm_alloc(struct bnx2fc_rport *tgt, int type)
 	struct bnx2fc_cmd *io_req;
 	struct list_head *listp;
 	struct io_bdt *bd_tbl;
+	int index = RESERVE_FREE_LIST_INDEX;
 	u32 max_sqes;
 	u16 xid;
 
@@ -432,26 +444,26 @@ struct bnx2fc_cmd *bnx2fc_elstm_alloc(struct bnx2fc_rport *tgt, int type)
 	 * NOTE: Free list insertions and deletions are protected with
 	 * cmgr lock
 	 */
-	spin_lock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
-	if ((list_empty(&(cmd_mgr->free_list[smp_processor_id()]))) ||
+	spin_lock_bh(&cmd_mgr->free_list_lock[index]);
+	if ((list_empty(&(cmd_mgr->free_list[index]))) ||
 	    (tgt->num_active_ios.counter  >= max_sqes)) {
 		BNX2FC_TGT_DBG(tgt, "No free els_tm cmds available "
 			"ios(%d):sqes(%d)\n",
 			tgt->num_active_ios.counter, tgt->max_sqes);
-		if (list_empty(&(cmd_mgr->free_list[smp_processor_id()])))
+		if (list_empty(&(cmd_mgr->free_list[index])))
 			printk(KERN_ERR PFX "elstm_alloc: list_empty\n");
-		spin_unlock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
+		spin_unlock_bh(&cmd_mgr->free_list_lock[index]);
 		return NULL;
 	}
 
 	listp = (struct list_head *)
-			cmd_mgr->free_list[smp_processor_id()].next;
+			cmd_mgr->free_list[index].next;
 	list_del_init(listp);
 	io_req = (struct bnx2fc_cmd *) listp;
 	xid = io_req->xid;
 	cmd_mgr->cmds[xid] = io_req;
 	atomic_inc(&tgt->num_active_ios);
-	spin_unlock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
+	spin_unlock_bh(&cmd_mgr->free_list_lock[index]);
 
 	INIT_LIST_HEAD(&io_req->link);
 
@@ -479,27 +491,30 @@ static struct bnx2fc_cmd *bnx2fc_cmd_alloc(struct bnx2fc_rport *tgt)
 	struct io_bdt *bd_tbl;
 	u32 max_sqes;
 	u16 xid;
+	int index = get_cpu();
 
 	max_sqes = BNX2FC_SCSI_MAX_SQES;
 	/*
 	 * NOTE: Free list insertions and deletions are protected with
 	 * cmgr lock
 	 */
-	spin_lock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
-	if ((list_empty(&cmd_mgr->free_list[smp_processor_id()])) ||
+	spin_lock_bh(&cmd_mgr->free_list_lock[index]);
+	if ((list_empty(&cmd_mgr->free_list[index])) ||
 	    (tgt->num_active_ios.counter  >= max_sqes)) {
-		spin_unlock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
+		spin_unlock_bh(&cmd_mgr->free_list_lock[index]);
+		put_cpu();
 		return NULL;
 	}
 
 	listp = (struct list_head *)
-		cmd_mgr->free_list[smp_processor_id()].next;
+		cmd_mgr->free_list[index].next;
 	list_del_init(listp);
 	io_req = (struct bnx2fc_cmd *) listp;
 	xid = io_req->xid;
 	cmd_mgr->cmds[xid] = io_req;
 	atomic_inc(&tgt->num_active_ios);
-	spin_unlock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
+	spin_unlock_bh(&cmd_mgr->free_list_lock[index]);
+	put_cpu();
 
 	INIT_LIST_HEAD(&io_req->link);
 
@@ -522,8 +537,15 @@ void bnx2fc_cmd_release(struct kref *ref)
 	struct bnx2fc_cmd *io_req = container_of(ref,
 						struct bnx2fc_cmd, refcount);
 	struct bnx2fc_cmd_mgr *cmd_mgr = io_req->cmd_mgr;
+	int index;
+
+	if (io_req->cmd_type == BNX2FC_SCSI_CMD)
+		index = io_req->xid % num_possible_cpus();
+	else
+		index = RESERVE_FREE_LIST_INDEX;
 
-	spin_lock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
+
+	spin_lock_bh(&cmd_mgr->free_list_lock[index]);
 	if (io_req->cmd_type != BNX2FC_SCSI_CMD)
 		bnx2fc_free_mp_resc(io_req);
 	cmd_mgr->cmds[io_req->xid] = NULL;
@@ -531,9 +553,10 @@ void bnx2fc_cmd_release(struct kref *ref)
 	list_del_init(&io_req->link);
 	/* Add it to the free list */
 	list_add(&io_req->link,
-			&cmd_mgr->free_list[smp_processor_id()]);
+			&cmd_mgr->free_list[index]);
 	atomic_dec(&io_req->tgt->num_active_ios);
-	spin_unlock_bh(&cmd_mgr->free_list_lock[smp_processor_id()]);
+	spin_unlock_bh(&cmd_mgr->free_list_lock[index]);
+
 }
 
 static void bnx2fc_free_mp_resc(struct bnx2fc_cmd *io_req)