01_scsi_remove_scsi_release_buffers.patch

        Buffer bouncing hasn't been done inside the scsi midlayer for
        quite sometime now, but bounce-buffer release paths are still
        around.  This patch removes these unused paths.

Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>

 scsi_lib.c |   60 +++++-------------------------------------------------------
 1 files changed, 5 insertions(+), 55 deletions(-)

Index: scsi-export/drivers/scsi/scsi_lib.c
===================================================================
--- scsi-export.orig/drivers/scsi/scsi_lib.c    2005-03-23 09:39:36.000000000 
+0900
+++ scsi-export/drivers/scsi/scsi_lib.c 2005-03-23 09:40:09.000000000 +0900
@@ -622,45 +622,6 @@ static void scsi_free_sgtable(struct sca
 }
 
 /*
- * Function:    scsi_release_buffers()
- *
- * Purpose:     Completion processing for block device I/O requests.
- *
- * Arguments:   cmd    - command that we are bailing.
- *
- * Lock status: Assumed that no lock is held upon entry.
- *
- * Returns:     Nothing
- *
- * 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.
- */
-static void scsi_release_buffers(struct scsi_cmnd *cmd)
-{
-       struct request *req = cmd->request;
-
-       /*
-        * Free up any indirection buffers we allocated for DMA purposes. 
-        */
-       if (cmd->use_sg)
-               scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
-       else if (cmd->request_buffer != req->buffer)
-               kfree(cmd->request_buffer);
-
-       /*
-        * Zero these out.  They now point to freed memory, and it is
-        * dangerous to hang onto the pointers.
-        */
-       cmd->buffer  = NULL;
-       cmd->bufflen = 0;
-       cmd->request_buffer = NULL;
-       cmd->request_bufflen = 0;
-}
-
-/*
  * Function:    scsi_io_completion()
  *
  * Purpose:     Completion processing for block device I/O requests.
@@ -703,22 +664,8 @@ void scsi_io_completion(struct scsi_cmnd
        if (blk_complete_barrier_rq(q, req, good_bytes >> 9))
                return;
 
-       /*
-        * Free up any indirection buffers we allocated for DMA purposes. 
-        * For the case of a READ, we need to copy the data out of the
-        * bounce buffer and into the real buffer.
-        */
        if (cmd->use_sg)
                scsi_free_sgtable(cmd->buffer, cmd->sglist_len);
-       else if (cmd->buffer != req->buffer) {
-               if (rq_data_dir(req) == READ) {
-                       unsigned long flags;
-                       char *to = bio_kmap_irq(req->bio, &flags);
-                       memcpy(to, cmd->buffer, cmd->bufflen);
-                       bio_kunmap_irq(to, &flags);
-               }
-               kfree(cmd->buffer);
-       }
 
        if (result) {
                sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
@@ -963,7 +910,8 @@ static int scsi_init_io(struct scsi_cmnd
                        req->current_nr_sectors);
 
        /* release the command and kill it */
-       scsi_release_buffers(cmd);
+       if (cmd->use_sg)
+               scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
        scsi_put_command(cmd);
        return BLKPREP_KILL;
 }
@@ -1140,7 +1088,9 @@ static int scsi_prep_fn(struct request_q
                 */
                drv = *(struct scsi_driver **)req->rq_disk->private_data;
                if (unlikely(!drv->init_command(cmd))) {
-                       scsi_release_buffers(cmd);
+                       if (cmd->use_sg)
+                               scsi_free_sgtable(cmd->request_buffer,
+                                                 cmd->sglist_len);
                        scsi_put_command(cmd);
                        return BLKPREP_KILL;
                }

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