scsi: fnic: replace gross legacy tag hack with blk-mq hack

Would be nice to fix up the SCSI midlayer instead, but this will do for
now.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Satish Kharat <satishkh@cisco.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 12 insertions, 49 deletions

diff --git a/drivers/scsi/fnic/fnic_scsi.c b/drivers/scsi/fnic/fnic_scsi.c
index 12a2f8fa4d19..96acfcecd540 100644
--- a/drivers/scsi/fnic/fnic_scsi.c
+++ b/drivers/scsi/fnic/fnic_scsi.c
@@ -2266,33 +2266,17 @@ clean_pending_aborts_end:
 static inline int
 fnic_scsi_host_start_tag(struct fnic *fnic, struct scsi_cmnd *sc)
 {
-        struct blk_queue_tag *bqt = fnic->lport->host->bqt;
-        int tag, ret = SCSI_NO_TAG;
+        struct request_queue *q = sc->request->q;
+        struct request *dummy;
 
-        BUG_ON(!bqt);
-        if (!bqt) {
-                pr_err("Tags are not supported\n");
-                goto end;
-        }
-
-        do {
-                tag = find_next_zero_bit(bqt->tag_map, bqt->max_depth, 1);
-                if (tag >= bqt->max_depth) {
-                        pr_err("Tag allocation failure\n");
-                        goto end;
-                }
-        } while (test_and_set_bit(tag, bqt->tag_map));
+        dummy = blk_mq_alloc_request(q, REQ_OP_WRITE, BLK_MQ_REQ_NOWAIT);
+        if (IS_ERR(dummy))
+                return SCSI_NO_TAG;
 
-        bqt->tag_index[tag] = sc->request;
-        sc->request->tag = tag;
-        sc->tag = tag;
-        if (!sc->request->special)
-                sc->request->special = sc;
+        sc->tag = sc->request->tag = dummy->tag;
+        sc->request->special = sc;
 
-        ret = tag;
-
-end:
-        return ret;
+        return dummy->tag;
 }
 
 /**
@@ -2302,20 +2286,9 @@ end:
 static inline void
 fnic_scsi_host_end_tag(struct fnic *fnic, struct scsi_cmnd *sc)
 {
-        struct blk_queue_tag *bqt = fnic->lport->host->bqt;
-        int tag = sc->request->tag;
-
-        if (tag == SCSI_NO_TAG)
-                return;
-
-        BUG_ON(!bqt || !bqt->tag_index[tag]);
-        if (!bqt)
-                return;
+        struct request *dummy = sc->request->special;
 
-        bqt->tag_index[tag] = NULL;
-        clear_bit(tag, bqt->tag_map);
-
-        return;
+        blk_mq_free_request(dummy);
 }
 
 /*
@@ -2374,19 +2347,9 @@ int fnic_device_reset(struct scsi_cmnd *sc)
         tag = sc->request->tag;
         if (unlikely(tag < 0)) {
                 /*
-                 * XXX(hch): current the midlayer fakes up a struct
-                 * request for the explicit reset ioctls, and those
-                 * don't have a tag allocated to them.  The below
-                 * code pokes into midlayer structures to paper over
-                 * this design issue, but that won't work for blk-mq.
-                 *
-                 * Either someone who can actually test the hardware
-                 * will have to come up with a similar hack for the
-                 * blk-mq case, or we'll have to bite the bullet and
-                 * fix the way the EH ioctls work for real, but until
-                 * that happens we fail these explicit requests here.
+                 * Really should fix the midlayer to pass in a proper
+                 * request for ioctls...
                  */
-
                 tag = fnic_scsi_host_start_tag(fnic, sc);
                 if (unlikely(tag == SCSI_NO_TAG))
                         goto fnic_device_reset_end;