Small ORDERED commands handling optimization

git-svn-id: https://scst.svn.sourceforge.net/svnroot/scst/trunk@19 d57e44dd-8a1f-0410-8b47-8ef2f437770f

diff --git a/scst/src/dev_handlers/scst_fileio.c b/scst/src/dev_handlers/scst_fileio.c
index f10a05c..58f7a04 100644 (file)
--- a/scst/src/dev_handlers/scst_fileio.c
+++ b/scst/src/dev_handlers/scst_fileio.c
@@ -105,6 +105,7 @@ struct scst_fileio_dev {
 
 struct scst_fileio_tgt_dev {
        spinlock_t fdev_lock;
+       enum scst_cmd_queue_type last_write_cmd_queue_type;
        int shutdown;
        struct file *fd;
        struct iovec *iv;
@@ -380,6 +381,26 @@ static void fileio_detach(struct scst_device *dev)
        return;
 }
 
+static inline int fileio_sync_queue_type(enum scst_cmd_queue_type qt)
+{
+       switch(qt) {
+               case SCST_CMD_QUEUE_ORDERED:
+               case SCST_CMD_QUEUE_HEAD_OF_QUEUE:
+                       return 1;
+               default:
+                       return 0;
+       }
+}
+
+static inline int fileio_need_pre_sync(enum scst_cmd_queue_type cwqt,
+       enum scst_cmd_queue_type lwqt)
+{
+       if (fileio_sync_queue_type(cwqt))
+               if (!fileio_sync_queue_type(lwqt))
+                       return 1;
+       return 0;
+}
+
 static void fileio_do_job(struct scst_cmd *cmd)
 {
        uint64_t lba_start;
@@ -482,11 +503,15 @@ static void fileio_do_job(struct scst_cmd *cmd)
                        struct scst_fileio_tgt_dev *ftgt_dev =
                                (struct scst_fileio_tgt_dev*)
                                        cmd->tgt_dev->dh_priv;
-                       if ((cmd->queue_type == SCST_CMD_QUEUE_ORDERED) && 
+                       enum scst_cmd_queue_type last_queue_type =
+                               ftgt_dev->last_write_cmd_queue_type;
+                       ftgt_dev->last_write_cmd_queue_type = cmd->queue_type;
+                       if (fileio_need_pre_sync(cmd->queue_type, last_queue_type) &&
                            !virt_dev->wt_flag) {
-                               TRACE(TRACE_SCSI/*|TRACE_SPECIAL*/, "ORDERED WRITE: "
-                                       "loff=%Ld, data_len=%Ld", (uint64_t)loff,
-                                       (uint64_t)data_len);
+                               TRACE(TRACE_SCSI/*|TRACE_SPECIAL*/, "ORDERED "
+                                       "WRITE(%d): loff=%Ld, data_len=%Ld",
+                                       cmd->queue_type, (uint64_t)loff,
+                                       (uint64_t)data_len);
                                do_fsync = 1;
                                if (fileio_fsync(ftgt_dev, 0, 0, cmd) != 0)
                                        goto done;
@@ -509,11 +534,15 @@ static void fileio_do_job(struct scst_cmd *cmd)
                        struct scst_fileio_tgt_dev *ftgt_dev =
                                (struct scst_fileio_tgt_dev*)
                                        cmd->tgt_dev->dh_priv;
-                       if ((cmd->queue_type == SCST_CMD_QUEUE_ORDERED) && 
+                       enum scst_cmd_queue_type last_queue_type =
+                               ftgt_dev->last_write_cmd_queue_type;
+                       ftgt_dev->last_write_cmd_queue_type = cmd->queue_type;
+                       if (fileio_need_pre_sync(cmd->queue_type, last_queue_type) && 
                            !virt_dev->wt_flag) {
                                TRACE(TRACE_SCSI/*|TRACE_SPECIAL*/, "ORDERED "
-                                       "WRITE_VERIFY: loff=%Ld, data_len=%Ld",
-                                       (uint64_t)loff, (uint64_t)data_len);
+                                       "WRITE_VERIFY(%d): loff=%Ld, data_len=%Ld",
+                                       cmd->queue_type, (uint64_t)loff,
+                                       (uint64_t)data_len);
                                do_fsync = 1;
                                if (fileio_fsync(ftgt_dev, 0, 0, cmd) != 0)
                                        goto done;