[SCSI] zfcp: Move FSF request tracking code to new file

Move the code for tracking FSF requests to new file to have this code
in one place. The functions for adding and removing requests on the
I/O path are already inline. The alloc and free functions are only
called once, so it does not hurt to inline them and add them to the
same file.

Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

8 files changed, 203 insertions, 98 deletions

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 9d0c941..f42da9d 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -32,6 +32,7 @@
 #include <linux/seq_file.h>
 #include "zfcp_ext.h"
 #include "zfcp_fc.h"
+#include "zfcp_reqlist.h"
 
 #define ZFCP_BUS_ID_SIZE	20
 
@@ -49,36 +50,6 @@ static struct kmem_cache *zfcp_cache_hw_align(const char *name,
 	return kmem_cache_create(name, size, roundup_pow_of_two(size), 0, NULL);
 }
 
-static int zfcp_reqlist_alloc(struct zfcp_adapter *adapter)
-{
-	int idx;
-
-	adapter->req_list = kcalloc(REQUEST_LIST_SIZE, sizeof(struct list_head),
-				    GFP_KERNEL);
-	if (!adapter->req_list)
-		return -ENOMEM;
-
-	for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
-		INIT_LIST_HEAD(&adapter->req_list[idx]);
-	return 0;
-}
-
-/**
- * zfcp_reqlist_isempty - is the request list empty
- * @adapter: pointer to struct zfcp_adapter
- *
- * Returns: true if list is empty, false otherwise
- */
-int zfcp_reqlist_isempty(struct zfcp_adapter *adapter)
-{
-	unsigned int idx;
-
-	for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
-		if (!list_empty(&adapter->req_list[idx]))
-			return 0;
-	return 1;
-}
-
 static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
 {
 	struct ccw_device *cdev;
@@ -539,7 +510,8 @@ struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device)
 	if (zfcp_allocate_low_mem_buffers(adapter))
 		goto failed;
 
-	if (zfcp_reqlist_alloc(adapter))
+	adapter->req_list = zfcp_reqlist_alloc();
+	if (!adapter->req_list)
 		goto failed;
 
 	if (zfcp_dbf_adapter_register(adapter))
@@ -560,8 +532,6 @@ struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device)
 	INIT_LIST_HEAD(&adapter->erp_ready_head);
 	INIT_LIST_HEAD(&adapter->erp_running_head);
 
-	spin_lock_init(&adapter->req_list_lock);
-
 	rwlock_init(&adapter->erp_lock);
 	rwlock_init(&adapter->abort_lock);
 
diff --git a/drivers/s390/scsi/zfcp_ccw.c b/drivers/s390/scsi/zfcp_ccw.c
index c22cb72..6f65a21 100644
--- a/drivers/s390/scsi/zfcp_ccw.c
+++ b/drivers/s390/scsi/zfcp_ccw.c
@@ -10,6 +10,7 @@
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
 #include "zfcp_ext.h"
+#include "zfcp_reqlist.h"
 
 #define ZFCP_MODEL_PRIV 0x4
 
@@ -162,7 +163,7 @@ static int zfcp_ccw_set_online(struct ccw_device *cdev)
 	}
 
 	/* initialize request counter */
-	BUG_ON(!zfcp_reqlist_isempty(adapter));
+	BUG_ON(!zfcp_reqlist_isempty(adapter->req_list));
 	adapter->req_no = 0;
 
 	zfcp_erp_modify_adapter_status(adapter, "ccsonl1", NULL,
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 6ed4865..ff4e2ca1 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -39,9 +39,7 @@
 #include <asm/sysinfo.h>
 #include "zfcp_fsf.h"
 
-/********************* GENERAL DEFINES *********************************/
-
-#define REQUEST_LIST_SIZE 128
+struct zfcp_reqlist;
 
 /********************* SCSI SPECIFIC DEFINES *********************************/
 #define ZFCP_SCSI_ER_TIMEOUT                    (10*HZ)
@@ -206,8 +204,7 @@ struct zfcp_adapter {
 	struct list_head	port_list;	   /* remote port list */
 	rwlock_t		port_list_lock;    /* port list lock */
 	unsigned long		req_no;		   /* unique FSF req number */
-	struct list_head	*req_list;	   /* list of pending reqs */
-	spinlock_t		req_list_lock;	   /* request list lock */
+	struct zfcp_reqlist	*req_list;
 	u32			fsf_req_seq_no;	   /* FSF cmnd seq number */
 	rwlock_t		abort_lock;        /* Protects against SCSI
 						      stack abort/command
@@ -351,31 +348,4 @@ struct zfcp_data {
 #define ZFCP_SET                0x00000100
 #define ZFCP_CLEAR              0x00000200
 
-/*
- * Helper functions for request ID management.
- */
-static inline int zfcp_reqlist_hash(unsigned long req_id)
-{
-	return req_id % REQUEST_LIST_SIZE;
-}
-
-static inline void zfcp_reqlist_remove(struct zfcp_adapter *adapter,
-				       struct zfcp_fsf_req *fsf_req)
-{
-	list_del(&fsf_req->list);
-}
-
-static inline struct zfcp_fsf_req *
-zfcp_reqlist_find(struct zfcp_adapter *adapter, unsigned long req_id)
-{
-	struct zfcp_fsf_req *request;
-	unsigned int idx;
-
-	idx = zfcp_reqlist_hash(req_id);
-	list_for_each_entry(request, &adapter->req_list[idx], list)
-		if (request->req_id == req_id)
-			return request;
-	return NULL;
-}
-
 #endif /* ZFCP_DEF_H */
diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index d40d5b0..fe8e4c2 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -11,6 +11,7 @@
 
 #include <linux/kthread.h>
 #include "zfcp_ext.h"
+#include "zfcp_reqlist.h"
 
 #define ZFCP_MAX_ERPS                   3
 
@@ -483,8 +484,8 @@ static void zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *act)
 	if (!act->fsf_req_id)
 		return;
 
-	spin_lock(&adapter->req_list_lock);
-	req = zfcp_reqlist_find(adapter, act->fsf_req_id);
+	spin_lock(&adapter->req_list->lock);
+	req = _zfcp_reqlist_find(adapter->req_list, act->fsf_req_id);
 	if (req && req->erp_action == act) {
 		if (act->status & (ZFCP_STATUS_ERP_DISMISSED |
 				   ZFCP_STATUS_ERP_TIMEDOUT)) {
@@ -498,7 +499,7 @@ static void zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *act)
 			act->fsf_req_id = 0;
 	} else
 		act->fsf_req_id = 0;
-	spin_unlock(&adapter->req_list_lock);
+	spin_unlock(&adapter->req_list->lock);
 }
 
 /**
diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index 66bdb34..85cb135 100644
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -21,7 +21,6 @@ extern struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *);
 extern struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *, u64, u32,
 					   u32);
 extern struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *, u64);
-extern int zfcp_reqlist_isempty(struct zfcp_adapter *);
 extern void zfcp_sg_free_table(struct scatterlist *, int);
 extern int zfcp_sg_setup_table(struct scatterlist *, int);
 extern void zfcp_device_unregister(struct device *,
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index fd2371b..36a6f4a 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -14,6 +14,7 @@
 #include "zfcp_ext.h"
 #include "zfcp_fc.h"
 #include "zfcp_dbf.h"
+#include "zfcp_reqlist.h"
 
 static void zfcp_fsf_request_timeout_handler(unsigned long data)
 {
@@ -457,15 +458,10 @@ static void zfcp_fsf_req_complete(struct zfcp_fsf_req *req)
 void zfcp_fsf_req_dismiss_all(struct zfcp_adapter *adapter)
 {
 	struct zfcp_fsf_req *req, *tmp;
-	unsigned long flags;
 	LIST_HEAD(remove_queue);
-	unsigned int i;
 
 	BUG_ON(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP);
-	spin_lock_irqsave(&adapter->req_list_lock, flags);
-	for (i = 0; i < REQUEST_LIST_SIZE; i++)
-		list_splice_init(&adapter->req_list[i], &remove_queue);
-	spin_unlock_irqrestore(&adapter->req_list_lock, flags);
+	zfcp_reqlist_move(adapter->req_list, &remove_queue);
 
 	list_for_each_entry_safe(req, tmp, &remove_queue, list) {
 		list_del(&req->list);
@@ -770,27 +766,17 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req)
 {
 	struct zfcp_adapter *adapter = req->adapter;
 	struct zfcp_qdio *qdio = adapter->qdio;
-	unsigned long	     flags;
-	int		     idx;
-	int		     with_qtcb = (req->qtcb != NULL);
+	int with_qtcb = (req->qtcb != NULL);
 	int req_id = req->req_id;
 
-	/* put allocated FSF request into hash table */
-	spin_lock_irqsave(&adapter->req_list_lock, flags);
-	idx = zfcp_reqlist_hash(req_id);
-	list_add_tail(&req->list, &adapter->req_list[idx]);
-	spin_unlock_irqrestore(&adapter->req_list_lock, flags);
+	zfcp_reqlist_add(adapter->req_list, req);
 
 	req->queue_req.qdio_outb_usage = atomic_read(&qdio->req_q.count);
 	req->issued = get_clock();
 	if (zfcp_qdio_send(qdio, &req->queue_req)) {
 		del_timer(&req->timer);
-		spin_lock_irqsave(&adapter->req_list_lock, flags);
 		/* lookup request again, list might have changed */
-		req = zfcp_reqlist_find(adapter, req_id);
-		if (req)
-			zfcp_reqlist_remove(adapter, req);
-		spin_unlock_irqrestore(&adapter->req_list_lock, flags);
+		zfcp_reqlist_find_rm(adapter->req_list, req_id);
 		zfcp_erp_adapter_reopen(adapter, 0, "fsrs__1", req);
 		return -EIO;
 	}
@@ -2518,15 +2504,14 @@ void zfcp_fsf_reqid_check(struct zfcp_qdio *qdio, int sbal_idx)
 	struct qdio_buffer *sbal = qdio->resp_q.sbal[sbal_idx];
 	struct qdio_buffer_element *sbale;
 	struct zfcp_fsf_req *fsf_req;
-	unsigned long flags, req_id;
+	unsigned long req_id;
 	int idx;
 
 	for (idx = 0; idx < QDIO_MAX_ELEMENTS_PER_BUFFER; idx++) {
 
 		sbale = &sbal->element[idx];
 		req_id = (unsigned long) sbale->addr;
-		spin_lock_irqsave(&adapter->req_list_lock, flags);
-		fsf_req = zfcp_reqlist_find(adapter, req_id);
+		fsf_req = zfcp_reqlist_find_rm(adapter->req_list, req_id);
 
 		if (!fsf_req)
 			/*
@@ -2536,9 +2521,6 @@ void zfcp_fsf_reqid_check(struct zfcp_qdio *qdio, int sbal_idx)
 			panic("error: unknown req_id (%lx) on adapter %s.\n",
 			      req_id, dev_name(&adapter->ccw_device->dev));
 
-		list_del(&fsf_req->list);
-		spin_unlock_irqrestore(&adapter->req_list_lock, flags);
-
 		fsf_req->queue_req.sbal_response = sbal_idx;
 		fsf_req->queue_req.qdio_inb_usage =
 			atomic_read(&qdio->resp_q.count);
diff --git a/drivers/s390/scsi/zfcp_reqlist.h b/drivers/s390/scsi/zfcp_reqlist.h
new file mode 100644
index 0000000..a72d1b7
--- /dev/null
+++ b/drivers/s390/scsi/zfcp_reqlist.h
@@ -0,0 +1,183 @@
+/*
+ * zfcp device driver
+ *
+ * Data structure and helper functions for tracking pending FSF
+ * requests.
+ *
+ * Copyright IBM Corporation 2009
+ */
+
+#ifndef ZFCP_REQLIST_H
+#define ZFCP_REQLIST_H
+
+/* number of hash buckets */
+#define ZFCP_REQ_LIST_BUCKETS 128
+
+/**
+ * struct zfcp_reqlist - Container for request list (reqlist)
+ * @lock: Spinlock for protecting the hash list
+ * @list: Array of hashbuckets, each is a list of requests in this bucket
+ */
+struct zfcp_reqlist {
+	spinlock_t lock;
+	struct list_head buckets[ZFCP_REQ_LIST_BUCKETS];
+};
+
+static inline int zfcp_reqlist_hash(unsigned long req_id)
+{
+	return req_id % ZFCP_REQ_LIST_BUCKETS;
+}
+
+/**
+ * zfcp_reqlist_alloc - Allocate and initialize reqlist
+ *
+ * Returns pointer to allocated reqlist on success, or NULL on
+ * allocation failure.
+ */
+static inline struct zfcp_reqlist *zfcp_reqlist_alloc(void)
+{
+	unsigned int i;
+	struct zfcp_reqlist *rl;
+
+	rl = kzalloc(sizeof(struct zfcp_reqlist), GFP_KERNEL);
+	if (!rl)
+		return NULL;
+
+	spin_lock_init(&rl->lock);
+
+	for (i = 0; i < ZFCP_REQ_LIST_BUCKETS; i++)
+		INIT_LIST_HEAD(&rl->buckets[i]);
+
+	return rl;
+}
+
+/**
+ * zfcp_reqlist_isempty - Check whether the request list empty
+ * @rl: pointer to reqlist
+ *
+ * Returns: 1 if list is empty, 0 if not
+ */
+static inline int zfcp_reqlist_isempty(struct zfcp_reqlist *rl)
+{
+	unsigned int i;
+
+	for (i = 0; i < ZFCP_REQ_LIST_BUCKETS; i++)
+		if (!list_empty(&rl->buckets[i]))
+			return 0;
+	return 1;
+}
+
+/**
+ * zfcp_reqlist_free - Free allocated memory for reqlist
+ * @rl: The reqlist where to free memory
+ */
+static inline void zfcp_reqlist_free(struct zfcp_reqlist *rl)
+{
+	/* sanity check */
+	BUG_ON(!zfcp_reqlist_isempty(rl));
+
+	kfree(rl);
+}
+
+static inline struct zfcp_fsf_req *
+_zfcp_reqlist_find(struct zfcp_reqlist *rl, unsigned long req_id)
+{
+	struct zfcp_fsf_req *req;
+	unsigned int i;
+
+	i = zfcp_reqlist_hash(req_id);
+	list_for_each_entry(req, &rl->buckets[i], list)
+		if (req->req_id == req_id)
+			return req;
+	return NULL;
+}
+
+/**
+ * zfcp_reqlist_find - Lookup FSF request by its request id
+ * @rl: The reqlist where to lookup the FSF request
+ * @req_id: The request id to look for
+ *
+ * Returns a pointer to the FSF request with the specified request id
+ * or NULL if there is no known FSF request with this id.
+ */
+static inline struct zfcp_fsf_req *
+zfcp_reqlist_find(struct zfcp_reqlist *rl, unsigned long req_id)
+{
+	unsigned long flags;
+	struct zfcp_fsf_req *req;
+
+	spin_lock_irqsave(&rl->lock, flags);
+	req = _zfcp_reqlist_find(rl, req_id);
+	spin_unlock_irqrestore(&rl->lock, flags);
+
+	return req;
+}
+
+/**
+ * zfcp_reqlist_find_rm - Lookup request by id and remove it from reqlist
+ * @rl: reqlist where to search and remove entry
+ * @req_id: The request id of the request to look for
+ *
+ * This functions tries to find the FSF request with the specified
+ * id and then removes it from the reqlist. The reqlist lock is held
+ * during both steps of the operation.
+ *
+ * Returns: Pointer to the FSF request if the request has been found,
+ * NULL if it has not been found.
+ */
+static inline struct zfcp_fsf_req *
+zfcp_reqlist_find_rm(struct zfcp_reqlist *rl, unsigned long req_id)
+{
+	unsigned long flags;
+	struct zfcp_fsf_req *req;
+
+	spin_lock_irqsave(&rl->lock, flags);
+	req = _zfcp_reqlist_find(rl, req_id);
+	if (req)
+		list_del(&req->list);
+	spin_unlock_irqrestore(&rl->lock, flags);
+
+	return req;
+}
+
+/**
+ * zfcp_reqlist_add - Add entry to reqlist
+ * @rl: reqlist where to add the entry
+ * @req: The entry to add
+ *
+ * The request id always increases. As an optimization new requests
+ * are added here with list_add_tail at the end of the bucket lists
+ * while old requests are looked up starting at the beginning of the
+ * lists.
+ */
+static inline void zfcp_reqlist_add(struct zfcp_reqlist *rl,
+				    struct zfcp_fsf_req *req)
+{
+	unsigned int i;
+	unsigned long flags;
+
+	i = zfcp_reqlist_hash(req->req_id);
+
+	spin_lock_irqsave(&rl->lock, flags);
+	list_add_tail(&req->list, &rl->buckets[i]);
+	spin_unlock_irqrestore(&rl->lock, flags);
+}
+
+/**
+ * zfcp_reqlist_move - Move all entries from reqlist to simple list
+ * @rl: The zfcp_reqlist where to remove all entries
+ * @list: The list where to move all entries
+ */
+static inline void zfcp_reqlist_move(struct zfcp_reqlist *rl,
+				     struct list_head *list)
+{
+	unsigned int i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rl->lock, flags);
+	for (i = 0; i < ZFCP_REQ_LIST_BUCKETS; i++)
+		list_splice_init(&rl->buckets[i], list);
+	spin_unlock_irqrestore(&rl->lock, flags);
+}
+
+#endif /* ZFCP_REQLIST_H */
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 8e6fc68..e1e56f5 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -15,6 +15,7 @@
 #include "zfcp_ext.h"
 #include "zfcp_dbf.h"
 #include "zfcp_fc.h"
+#include "zfcp_reqlist.h"
 
 static unsigned int default_depth = 32;
 module_param_named(queue_depth, default_depth, uint, 0600);
@@ -189,9 +190,7 @@ static int zfcp_scsi_eh_abort_handler(struct scsi_cmnd *scpnt)
 	/* avoid race condition between late normal completion and abort */
 	write_lock_irqsave(&adapter->abort_lock, flags);
 
-	spin_lock(&adapter->req_list_lock);
-	old_req = zfcp_reqlist_find(adapter, old_reqid);
-	spin_unlock(&adapter->req_list_lock);
+	old_req = zfcp_reqlist_find(adapter->req_list, old_reqid);
 	if (!old_req) {
 		write_unlock_irqrestore(&adapter->abort_lock, flags);
 		zfcp_dbf_scsi_abort("lte1", adapter->dbf, scpnt, NULL,