1 #ifndef _SCSI_SCSI_TCQ_H 2 #define _SCSI_SCSI_TCQ_H 3 4 #include <linux/blkdev.h> 5 #include <scsi/scsi_cmnd.h> 6 #include <scsi/scsi_device.h> 7 #include <scsi/scsi_host.h> 8 9 #define MSG_SIMPLE_TAG 0x20 10 #define MSG_HEAD_TAG 0x21 11 #define MSG_ORDERED_TAG 0x22 12 13 #define SCSI_NO_TAG (-1) /* identify no tag in use */ 14 15 16 #ifdef CONFIG_BLOCK 17 18 /** 19 * scsi_get_tag_type - get the type of tag the device supports 20 * @sdev: the scsi device 21 * 22 * Notes: 23 * If the drive only supports simple tags, returns MSG_SIMPLE_TAG 24 * if it supports all tag types, returns MSG_ORDERED_TAG. 25 */ 26 static inline int scsi_get_tag_type(struct scsi_device *sdev) 27 { 28 if (!sdev->tagged_supported) 29 return 0; 30 if (sdev->ordered_tags) 31 return MSG_ORDERED_TAG; 32 if (sdev->simple_tags) 33 return MSG_SIMPLE_TAG; 34 return 0; 35 } 36 37 static inline void scsi_set_tag_type(struct scsi_device *sdev, int tag) 38 { 39 switch (tag) { 40 case MSG_ORDERED_TAG: 41 sdev->ordered_tags = 1; 42 /* fall through */ 43 case MSG_SIMPLE_TAG: 44 sdev->simple_tags = 1; 45 break; 46 case 0: 47 /* fall through */ 48 default: 49 sdev->ordered_tags = 0; 50 sdev->simple_tags = 0; 51 break; 52 } 53 } 54 /** 55 * scsi_activate_tcq - turn on tag command queueing 56 * @SDpnt: device to turn on TCQ for 57 * @depth: queue depth 58 * 59 * Notes: 60 * Eventually, I hope depth would be the maximum depth 61 * the device could cope with and the real queue depth 62 * would be adjustable from 0 to depth. 63 **/ 64 static inline void scsi_activate_tcq(struct scsi_device *sdev, int depth) 65 { 66 if (!sdev->tagged_supported) 67 return; 68 69 if (!blk_queue_tagged(sdev->request_queue)) 70 blk_queue_init_tags(sdev->request_queue, depth, 71 sdev->host->bqt); 72 73 scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth); 74 } 75 76 /** 77 * scsi_deactivate_tcq - turn off tag command queueing 78 * @SDpnt: device to turn off TCQ for 79 **/ 80 static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth) 81 { 82 if (blk_queue_tagged(sdev->request_queue)) 83 blk_queue_free_tags(sdev->request_queue); 84 scsi_adjust_queue_depth(sdev, 0, depth); 85 } 86 87 /** 88 * scsi_populate_tag_msg - place a tag message in a buffer 89 * @SCpnt: pointer to the Scsi_Cmnd for the tag 90 * @msg: pointer to the area to place the tag 91 * 92 * Notes: 93 * designed to create the correct type of tag message for the 94 * particular request. Returns the size of the tag message. 95 * May return 0 if TCQ is disabled for this device. 96 **/ 97 static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg) 98 { 99 struct request *req = cmd->request; 100 101 if (blk_rq_tagged(req)) { 102 *msg++ = MSG_SIMPLE_TAG; 103 *msg++ = req->tag; 104 return 2; 105 } 106 107 return 0; 108 } 109 110 /** 111 * scsi_find_tag - find a tagged command by device 112 * @SDpnt: pointer to the ScSI device 113 * @tag: the tag number 114 * 115 * Notes: 116 * Only works with tags allocated by the generic blk layer. 117 **/ 118 static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag) 119 { 120 121 struct request *req; 122 123 if (tag != SCSI_NO_TAG) { 124 req = blk_queue_find_tag(sdev->request_queue, tag); 125 return req ? (struct scsi_cmnd *)req->special : NULL; 126 } 127 128 /* single command, look in space */ 129 return sdev->current_cmnd; 130 } 131 132 /** 133 * scsi_init_shared_tag_map - create a shared tag map 134 * @shost: the host to share the tag map among all devices 135 * @depth: the total depth of the map 136 */ 137 static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth) 138 { 139 /* 140 * If the shared tag map isn't already initialized, do it now. 141 * This saves callers from having to check ->bqt when setting up 142 * devices on the shared host (for libata) 143 */ 144 if (!shost->bqt) { 145 shost->bqt = blk_init_tags(depth); 146 if (!shost->bqt) 147 return -ENOMEM; 148 } 149 150 return 0; 151 } 152 153 /** 154 * scsi_host_find_tag - find the tagged command by host 155 * @shost: pointer to scsi_host 156 * @tag: tag of the scsi_cmnd 157 * 158 * Notes: 159 * Only works with tags allocated by the generic blk layer. 160 **/ 161 static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost, 162 int tag) 163 { 164 struct request *req; 165 166 if (tag != SCSI_NO_TAG) { 167 req = blk_map_queue_find_tag(shost->bqt, tag); 168 return req ? (struct scsi_cmnd *)req->special : NULL; 169 } 170 return NULL; 171 } 172 173 #endif /* CONFIG_BLOCK */ 174 #endif /* _SCSI_SCSI_TCQ_H */ 175