Re: [PATCH scsi-misc-2.6 01/08] scsi: remove unused bounce-buffer release path

Tejun Heo
2005-03-23T02:15:31Z

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 <htejun@gmail.com>

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;
}