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| author | Christoph Hellwig <hch@infradead.org> | 2014-02-20 14:20:55 -0800 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2014-03-15 10:19:24 -0700 |
| commit | 0479633686d370303e3430256ace4bd5f7f138dc (patch) | |
| tree | 8315562a82e4c64712d2d8ee423be2f346aa27c5 /drivers/scsi/scsi_lib.c | |
| parent | 21a05df547dd0ac532d3a89e241dc504018eb881 (diff) | |
| download | lwn-0479633686d370303e3430256ace4bd5f7f138dc.tar.gz lwn-0479633686d370303e3430256ace4bd5f7f138dc.zip | |
[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.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 492071ca45d1..007e979fa437 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; |