ieee1394: sbp2: convert sbp2util_down_timeout to waitqueue

The waitqueue API is used to replace a custom wait mechanism.  Only one
global waitqueue (instead of per-device waitqueues or completions) is
added because there is usually just one waiter.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

2 files changed, 24 insertions, 31 deletions

diff --git a/drivers/ieee1394/sbp2.c b/drivers/ieee1394/sbp2.c
index 07030be0ef2..6adbe1c796c 100644
--- a/drivers/ieee1394/sbp2.c
+++ b/drivers/ieee1394/sbp2.c
@@ -55,12 +55,12 @@
 #include <linux/smp_lock.h>
 #include <linux/init.h>
 #include <linux/pci.h>
+#include <linux/wait.h>
 
 #include <asm/current.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/byteorder.h>
-#include <asm/atomic.h>
 #include <asm/system.h>
 #include <asm/scatterlist.h>
 
@@ -420,21 +420,23 @@ static void sbp2util_packet_dump(void *buffer, int length, char *dump_name,
 #define sbp2util_packet_dump(w,x,y,z)
 #endif
 
+static DECLARE_WAIT_QUEUE_HEAD(access_wq);
+
 /*
- * Goofy routine that basically does a down_timeout function.
+ * Waits for completion of an SBP-2 access request.
+ * Returns nonzero if timed out or prematurely interrupted.
  */
-static int sbp2util_down_timeout(atomic_t *done, int timeout)
+static int sbp2util_access_timeout(struct scsi_id_instance_data *scsi_id,
+                                   int timeout)
 {
-        int i;
+        long leftover = wait_event_interruptible_timeout(
+                                access_wq, scsi_id->access_complete, timeout);
 
-        for (i = timeout; (i > 0 && atomic_read(done) == 0); i-= HZ/10) {
-                if (msleep_interruptible(100))  /* 100ms */
-                        return 1;
-        }
-        return (i > 0) ? 0 : 1;
+        scsi_id->access_complete = 0;
+        return leftover <= 0;
 }
 
-/* Free's an allocated packet */
+/* Frees an allocated packet */
 static void sbp2_free_packet(struct hpsb_packet *packet)
 {
         hpsb_free_tlabel(packet);
@@ -794,7 +796,6 @@ static struct scsi_id_instance_data *sbp2_alloc_device(struct unit_directory *ud
         scsi_id->speed_code = IEEE1394_SPEED_100;
         scsi_id->max_payload_size = sbp2_speedto_max_payload[IEEE1394_SPEED_100];
         scsi_id->status_fifo_addr = CSR1212_INVALID_ADDR_SPACE;
-        atomic_set(&scsi_id->sbp2_login_complete, 0);
         INIT_LIST_HEAD(&scsi_id->sbp2_command_orb_inuse);
         INIT_LIST_HEAD(&scsi_id->sbp2_command_orb_completed);
         INIT_LIST_HEAD(&scsi_id->scsi_list);
@@ -1187,11 +1188,9 @@ static int sbp2_query_logins(struct scsi_id_instance_data *scsi_id)
         data[1] = scsi_id->query_logins_orb_dma;
         sbp2util_cpu_to_be32_buffer(data, 8);
 
-        atomic_set(&scsi_id->sbp2_login_complete, 0);
-
         hpsb_node_write(scsi_id->ne, scsi_id->sbp2_management_agent_addr, data, 8);
 
-        if (sbp2util_down_timeout(&scsi_id->sbp2_login_complete, 2*HZ)) {
+        if (sbp2util_access_timeout(scsi_id, 2*HZ)) {
                 SBP2_INFO("Error querying logins to SBP-2 device - timed out");
                 return -EIO;
         }
@@ -1279,15 +1278,13 @@ static int sbp2_login_device(struct scsi_id_instance_data *scsi_id)
         data[1] = scsi_id->login_orb_dma;
         sbp2util_cpu_to_be32_buffer(data, 8);
 
-        atomic_set(&scsi_id->sbp2_login_complete, 0);
-
         hpsb_node_write(scsi_id->ne, scsi_id->sbp2_management_agent_addr, data, 8);
 
         /*
          * Wait for login status (up to 20 seconds)...
          */
-        if (sbp2util_down_timeout(&scsi_id->sbp2_login_complete, 20*HZ)) {
-                SBP2_ERR("Error logging into SBP-2 device - login timed-out");
+        if (sbp2util_access_timeout(scsi_id, 20*HZ)) {
+                SBP2_ERR("Error logging into SBP-2 device - timed out");
                 return -EIO;
         }
 
@@ -1374,21 +1371,17 @@ static int sbp2_logout_device(struct scsi_id_instance_data *scsi_id)
         data[1] = scsi_id->logout_orb_dma;
         sbp2util_cpu_to_be32_buffer(data, 8);
 
-        atomic_set(&scsi_id->sbp2_login_complete, 0);
-
         error = hpsb_node_write(scsi_id->ne,
                                 scsi_id->sbp2_management_agent_addr, data, 8);
         if (error)
                 return error;
 
         /* Wait for device to logout...1 second. */
-        if (sbp2util_down_timeout(&scsi_id->sbp2_login_complete, HZ))
+        if (sbp2util_access_timeout(scsi_id, HZ))
                 return -EIO;
 
         SBP2_INFO("Logged out of SBP-2 device");
-
         return 0;
-
 }
 
 /*
@@ -1436,8 +1429,6 @@ static int sbp2_reconnect_device(struct scsi_id_instance_data *scsi_id)
         data[1] = scsi_id->reconnect_orb_dma;
         sbp2util_cpu_to_be32_buffer(data, 8);
 
-        atomic_set(&scsi_id->sbp2_login_complete, 0);
-
         error = hpsb_node_write(scsi_id->ne,
                                 scsi_id->sbp2_management_agent_addr, data, 8);
         if (error)
@@ -1446,8 +1437,8 @@ static int sbp2_reconnect_device(struct scsi_id_instance_data *scsi_id)
         /*
          * Wait for reconnect status (up to 1 second)...
          */
-        if (sbp2util_down_timeout(&scsi_id->sbp2_login_complete, HZ)) {
-                SBP2_ERR("Error reconnecting to SBP-2 device - reconnect timed-out");
+        if (sbp2util_access_timeout(scsi_id, HZ)) {
+                SBP2_ERR("Error reconnecting to SBP-2 device - timed out");
                 return -EIO;
         }
 
@@ -2215,8 +2206,10 @@ static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
                 if ((sb->ORB_offset_lo == scsi_id->reconnect_orb_dma) ||
                     (sb->ORB_offset_lo == scsi_id->login_orb_dma) ||
                     (sb->ORB_offset_lo == scsi_id->query_logins_orb_dma) ||
-                    (sb->ORB_offset_lo == scsi_id->logout_orb_dma))
-                        atomic_set(&scsi_id->sbp2_login_complete, 1);
+                    (sb->ORB_offset_lo == scsi_id->logout_orb_dma)) {
+                        scsi_id->access_complete = 1;
+                        wake_up_interruptible(&access_wq);
+                }
         }
 
         if (SCpnt) {
diff --git a/drivers/ieee1394/sbp2.h b/drivers/ieee1394/sbp2.h
index 34e3d37fc79..89098fe565e 100644
--- a/drivers/ieee1394/sbp2.h
+++ b/drivers/ieee1394/sbp2.h
@@ -320,9 +320,9 @@ struct scsi_id_instance_data {
         u64 status_fifo_addr;
 
         /*
-         * Variable used for logins, reconnects, logouts, query logins
+         * Waitqueue flag for logins, reconnects, logouts, query logins
          */
-        atomic_t sbp2_login_complete;
+        int access_complete:1;
 
         /*
          * Pool of command orbs, so we can have more than overlapped command per id