scsi: explicitly release bidi buffers

Instead of trying to guess when we have a BIDI buffer in scsi_release_buffers
add a function to explicitly free the BIDI ressoures in the one place that
handles them.  This avoids needing a special __scsi_release_buffers for the
case where we already have freed the request as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>

1 files changed, 20 insertions, 27 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9db097a28a74..f416b5932a45 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -512,8 +512,6 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
                 scsi_run_queue(sdev->request_queue);
 }
 
-static void __scsi_release_buffers(struct scsi_cmnd *, int);
-
 /*
  * Function:    scsi_end_request()
  *
@@ -569,7 +567,7 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
          * This will goose the queue request function at the end, so we don't
          * need to worry about launching another command.
          */
-        __scsi_release_buffers(cmd, 0);
+        scsi_release_buffers(cmd);
         scsi_next_command(cmd);
         return NULL;
 }
@@ -625,30 +623,10 @@ static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
         __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
 }
 
-static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
-{
-
-        if (cmd->sdb.table.nents)
-                scsi_free_sgtable(&cmd->sdb);
-
-        memset(&cmd->sdb, 0, sizeof(cmd->sdb));
-
-        if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
-                struct scsi_data_buffer *bidi_sdb =
-                        cmd->request->next_rq->special;
-                scsi_free_sgtable(bidi_sdb);
-                kmem_cache_free(scsi_sdb_cache, bidi_sdb);
-                cmd->request->next_rq->special = NULL;
-        }
-
-        if (scsi_prot_sg_count(cmd))
-                scsi_free_sgtable(cmd->prot_sdb);
-}
-
 /*
  * Function:    scsi_release_buffers()
  *
- * Purpose:     Completion processing for block device I/O requests.
+ * Purpose:     Free resources allocate for a scsi_command.
  *
  * Arguments:   cmd     - command that we are bailing.
  *
@@ -659,15 +637,29 @@ static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
  * Notes:       In the event that an upper level driver rejects a
  *              command, we must release resources allocated during
  *              the __init_io() function.  Primarily this would involve
- *              the scatter-gather table, and potentially any bounce
- *              buffers.
+ *              the scatter-gather table.
  */
 void scsi_release_buffers(struct scsi_cmnd *cmd)
 {
-        __scsi_release_buffers(cmd, 1);
+        if (cmd->sdb.table.nents)
+                scsi_free_sgtable(&cmd->sdb);
+
+        memset(&cmd->sdb, 0, sizeof(cmd->sdb));
+
+        if (scsi_prot_sg_count(cmd))
+                scsi_free_sgtable(cmd->prot_sdb);
 }
 EXPORT_SYMBOL(scsi_release_buffers);
 
+static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
+{
+        struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
+
+        scsi_free_sgtable(bidi_sdb);
+        kmem_cache_free(scsi_sdb_cache, bidi_sdb);
+        cmd->request->next_rq->special = NULL;
+}
+
 /**
  * __scsi_error_from_host_byte - translate SCSI error code into errno
  * @cmd:        SCSI command (unused)
@@ -801,6 +793,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                         req->next_rq->resid_len = scsi_in(cmd)->resid;
 
                         scsi_release_buffers(cmd);
+                        scsi_release_bidi_buffers(cmd);
                         blk_end_request_all(req, 0);
 
                         scsi_next_command(cmd);