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authorChristoph Hellwig <hch@infradead.org>2014-02-20 22:20:55 (GMT)
committerJames Bottomley <JBottomley@Parallels.com>2014-03-15 17:19:24 (GMT)
commit0479633686d370303e3430256ace4bd5f7f138dc (patch)
tree8315562a82e4c64712d2d8ee423be2f346aa27c5 /drivers/scsi/scsi_lib.c
parent21a05df547dd0ac532d3a89e241dc504018eb881 (diff)
downloadlinux-0479633686d370303e3430256ace4bd5f7f138dc.tar.xz
[SCSI] do not manipulate device reference counts in scsi_get/put_command
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>
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r--drivers/scsi/scsi_lib.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 492071c..007e979 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -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) {
+ /* 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))
+ 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;