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[SCSI] do not manipulate device reference counts in scsi_get/put_command

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Many callers won't need this and we can optimize them away.  In addition
the handling in the __-prefixed variants was inconsistant to start with.

Based on an earlier patch from Bart Van Assche.

[jejb: fix kerneldoc probelm picked up by Fengguang Wu]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Christoph Hellwig
2014-02-20 14:20:55 -08:00
committed by James Bottomley
parent 21a05df547
commit 0479633686
5 changed files with 33 additions and 30 deletions
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14
drivers/scsi/scsi_lib.c
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@@ -95,6 +95,7 @@ static void scsi_unprep_request(struct request *req)
req->special = NULL;
scsi_put_command(cmd);
put_device(&cmd->device->sdev_gendev);
}
/**
@@ -529,6 +530,7 @@ void scsi_next_command(struct scsi_cmnd *cmd)
get_device(&sdev->sdev_gendev);
scsi_put_command(cmd);
put_device(&sdev->sdev_gendev);
scsi_run_queue(q);
/* ok to remove device now */
@@ -1123,6 +1125,7 @@ err_exit:
scsi_release_buffers(cmd);
cmd->request->special = NULL;
scsi_put_command(cmd);
put_device(&cmd->device->sdev_gendev);
return error;
}
EXPORT_SYMBOL(scsi_init_io);
@@ -1133,9 +1136,15 @@ static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
struct scsi_cmnd *cmd;
if (!req->special) {
cmd = scsi_get_command(sdev, GFP_ATOMIC);
if (unlikely(!cmd))
/* Bail if we can't get a reference to the device */
if (!get_device(&sdev->sdev_gendev))
return NULL;
cmd = scsi_get_command(sdev, GFP_ATOMIC);
if (unlikely(!cmd)) {
put_device(&sdev->sdev_gendev);
return NULL;
}
req->special = cmd;
} else {
cmd = req->special;
@@ -1298,6 +1307,7 @@ int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
struct scsi_cmnd *cmd = req->special;
scsi_release_buffers(cmd);
scsi_put_command(cmd);
put_device(&cmd->device->sdev_gendev);
req->special = NULL;
}
break;