[PATCH] helper function for retrieving scsi_cmd given host based block layer tag
This was necessitated by the need for a function to get back to a scsi_cmnd, when an hba the posts its (corresponding) completion interrupt with a block layer tag as its reference. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: David Somayajulu <david.somayajulu@qlogic.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Jens Axboe
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4a61f17378
commit
f583f4924d
@ -144,5 +144,25 @@ static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
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return shost->bqt ? 0 : -ENOMEM;
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}
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/**
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* scsi_host_find_tag - find the tagged command by host
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* @shost: pointer to scsi_host
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* @tag: tag of the scsi_cmnd
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*
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* Notes:
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* Only works with tags allocated by the generic blk layer.
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**/
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static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
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int tag)
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{
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struct request *req;
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if (tag != SCSI_NO_TAG) {
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req = blk_map_queue_find_tag(shost->bqt, tag);
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return req ? (struct scsi_cmnd *)req->special : NULL;
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}
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return NULL;
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}
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#endif /* CONFIG_BLOCK */
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#endif /* _SCSI_SCSI_TCQ_H */
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