skd: Introduce skd_process_request()

The only functional change in this patch is that the skd_fitmsg_context
in which requests are accumulated is changed from a local variable into
a member of struct skd_device. This patch will make the blk-mq conversion
easier.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
index 4b92d711d2d34e33fb288d7af6775f942eb5273e..1d10373b0da365158d77f9905e218ce5bd62773c 100644 (file)
--- a/drivers/block/skd_main.c
+++ b/drivers/block/skd_main.c
@@ -232,6 +232,7 @@ struct skd_device {
        spinlock_t lock;
        struct gendisk *disk;
        struct request_queue *queue;
+       struct skd_fitmsg_context *skmsg;
        struct device *class_dev;
        int gendisk_on;
        int sync_done;
@@ -492,23 +493,128 @@ static bool skd_fail_all(struct request_queue *q)
        }
 }
 
-static void skd_request_fn(struct request_queue *q)
+static void skd_process_request(struct request *req)
 {
+       struct request_queue *const q = req->q;
        struct skd_device *skdev = q->queuedata;
-       struct skd_fitmsg_context *skmsg = NULL;
-       struct fit_msg_hdr *fmh = NULL;
-       struct skd_request_context *skreq;
-       struct request *req = NULL;
+       struct skd_fitmsg_context *skmsg;
+       struct fit_msg_hdr *fmh;
+       const u32 tag = blk_mq_unique_tag(req);
+       struct skd_request_context *const skreq = &skdev->skreq_table[tag];
        struct skd_scsi_request *scsi_req;
        unsigned long io_flags;
        u32 lba;
        u32 count;
        int data_dir;
        __be64 be_dmaa;
-       u64 cmdctxt;
        u32 timo_slot;
        int flush, fua;
-       u32 tag;
+
+       WARN_ONCE(tag >= skd_max_queue_depth, "%#x > %#x (nr_requests = %lu)\n",
+                 tag, skd_max_queue_depth, q->nr_requests);
+
+       SKD_ASSERT(skreq->state == SKD_REQ_STATE_IDLE);
+
+       flush = fua = 0;
+
+       lba = (u32)blk_rq_pos(req);
+       count = blk_rq_sectors(req);
+       data_dir = rq_data_dir(req);
+       io_flags = req->cmd_flags;
+
+       if (req_op(req) == REQ_OP_FLUSH)
+               flush++;
+
+       if (io_flags & REQ_FUA)
+               fua++;
+
+       dev_dbg(&skdev->pdev->dev,
+               "new req=%p lba=%u(0x%x) count=%u(0x%x) dir=%d\n", req, lba,
+               lba, count, count, data_dir);
+
+       skreq->id = tag + SKD_ID_RW_REQUEST;
+       skreq->flush_cmd = 0;
+       skreq->n_sg = 0;
+       skreq->sg_byte_count = 0;
+
+       skreq->req = req;
+       skreq->fitmsg_id = 0;
+
+       skreq->data_dir = data_dir == READ ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+
+       if (req->bio && !skd_preop_sg_list(skdev, skreq)) {
+               dev_dbg(&skdev->pdev->dev, "error Out\n");
+               skd_end_request(skdev, skreq->req, BLK_STS_RESOURCE);
+               return;
+       }
+
+       /* Either a FIT msg is in progress or we have to start one. */
+       skmsg = skdev->skmsg;
+       if (!skmsg) {
+               skmsg = &skdev->skmsg_table[tag];
+               skdev->skmsg = skmsg;
+
+               /* Initialize the FIT msg header */
+               fmh = &skmsg->msg_buf->fmh;
+               memset(fmh, 0, sizeof(*fmh));
+               fmh->protocol_id = FIT_PROTOCOL_ID_SOFIT;
+               skmsg->length = sizeof(*fmh);
+       } else {
+               fmh = &skmsg->msg_buf->fmh;
+       }
+
+       skreq->fitmsg_id = skmsg->id;
+
+       scsi_req = &skmsg->msg_buf->scsi[fmh->num_protocol_cmds_coalesced];
+       memset(scsi_req, 0, sizeof(*scsi_req));
+
+       be_dmaa = cpu_to_be64(skreq->sksg_dma_address);
+
+       scsi_req->hdr.tag = skreq->id;
+       scsi_req->hdr.sg_list_dma_address = be_dmaa;
+
+       if (flush == SKD_FLUSH_ZERO_SIZE_FIRST) {
+               skd_prep_zerosize_flush_cdb(scsi_req, skreq);
+               SKD_ASSERT(skreq->flush_cmd == 1);
+       } else {
+               skd_prep_rw_cdb(scsi_req, data_dir, lba, count);
+       }
+
+       if (fua)
+               scsi_req->cdb[1] |= SKD_FUA_NV;
+
+       scsi_req->hdr.sg_list_len_bytes = cpu_to_be32(skreq->sg_byte_count);
+
+       /* Complete resource allocations. */
+       skreq->state = SKD_REQ_STATE_BUSY;
+
+       skmsg->length += sizeof(struct skd_scsi_request);
+       fmh->num_protocol_cmds_coalesced++;
+
+       /*
+        * Update the active request counts.
+        * Capture the timeout timestamp.
+        */
+       skreq->timeout_stamp = atomic_read(&skdev->timeout_stamp);
+       timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
+       atomic_inc(&skdev->timeout_slot[timo_slot]);
+       atomic_inc(&skdev->in_flight);
+       dev_dbg(&skdev->pdev->dev, "req=0x%x busy=%d\n", skreq->id,
+               atomic_read(&skdev->in_flight));
+
+       /*
+        * If the FIT msg buffer is full send it.
+        */
+       if (fmh->num_protocol_cmds_coalesced >= skd_max_req_per_msg) {
+               skd_send_fitmsg(skdev, skmsg);
+               skdev->skmsg = NULL;
+       }
+}
+
+static void skd_request_fn(struct request_queue *q)
+{
+       struct skd_device *skdev = q->queuedata;
+       struct request *req;
 
        if (skdev->state != SKD_DRVR_STATE_ONLINE) {
                if (skd_fail_all(q))
@@ -533,30 +639,12 @@ static void skd_request_fn(struct request_queue *q)
         *  - There are no more FIT msg buffers
         */
        for (;; ) {
-
-               flush = fua = 0;
-
                req = blk_peek_request(q);
 
                /* Are there any native requests to start? */
                if (req == NULL)
                        break;
 
-               lba = (u32)blk_rq_pos(req);
-               count = blk_rq_sectors(req);
-               data_dir = rq_data_dir(req);
-               io_flags = req->cmd_flags;
-
-               if (req_op(req) == REQ_OP_FLUSH)
-                       flush++;
-
-               if (io_flags & REQ_FUA)
-                       fua++;
-
-               dev_dbg(&skdev->pdev->dev,
-                       "new req=%p lba=%u(0x%x) count=%u(0x%x) dir=%d\n",
-                       req, lba, lba, count, count, data_dir);
-
                /* At this point we know there is a request */
 
                /* Are too many requets already in progress? */
@@ -576,103 +664,16 @@ static void skd_request_fn(struct request_queue *q)
                 * available but is still at the head of the free list.
                 */
                WARN_ON_ONCE(blk_queue_start_tag(q, req));
-
-               tag = blk_mq_unique_tag(req);
-               WARN_ONCE(tag >= skd_max_queue_depth,
-                         "%#x > %#x (nr_requests = %lu)\n", tag,
-                         skd_max_queue_depth, q->nr_requests);
-
-               skreq = &skdev->skreq_table[tag];
-               SKD_ASSERT(skreq->state == SKD_REQ_STATE_IDLE);
-               SKD_ASSERT((skreq->id & SKD_ID_INCR) == 0);
-
-               skreq->id = tag + SKD_ID_RW_REQUEST;
-               skreq->flush_cmd = 0;
-               skreq->n_sg = 0;
-               skreq->sg_byte_count = 0;
-
-               skreq->req = req;
-               skreq->fitmsg_id = 0;
-
-               skreq->data_dir = data_dir == READ ? DMA_FROM_DEVICE :
-                       DMA_TO_DEVICE;
-
-               if (req->bio && !skd_preop_sg_list(skdev, skreq)) {
-                       dev_dbg(&skdev->pdev->dev, "error Out\n");
-                       skd_end_request(skdev, skreq->req, BLK_STS_RESOURCE);
-                       continue;
-               }
-
-               /* Either a FIT msg is in progress or we have to start one. */
-               if (skmsg == NULL) {
-                       skmsg = &skdev->skmsg_table[tag];
-
-                       /* Initialize the FIT msg header */
-                       fmh = &skmsg->msg_buf->fmh;
-                       memset(fmh, 0, sizeof(*fmh));
-                       fmh->protocol_id = FIT_PROTOCOL_ID_SOFIT;
-                       skmsg->length = sizeof(*fmh);
-               }
-
-               skreq->fitmsg_id = skmsg->id;
-
-               scsi_req =
-                       &skmsg->msg_buf->scsi[fmh->num_protocol_cmds_coalesced];
-               memset(scsi_req, 0, sizeof(*scsi_req));
-
-               be_dmaa = cpu_to_be64(skreq->sksg_dma_address);
-               cmdctxt = skreq->id + SKD_ID_INCR;
-
-               scsi_req->hdr.tag = cmdctxt;
-               scsi_req->hdr.sg_list_dma_address = be_dmaa;
-
-               if (flush == SKD_FLUSH_ZERO_SIZE_FIRST) {
-                       skd_prep_zerosize_flush_cdb(scsi_req, skreq);
-                       SKD_ASSERT(skreq->flush_cmd == 1);
-               } else {
-                       skd_prep_rw_cdb(scsi_req, data_dir, lba, count);
-               }
-
-               if (fua)
-                       scsi_req->cdb[1] |= SKD_FUA_NV;
-
-               scsi_req->hdr.sg_list_len_bytes =
-                       cpu_to_be32(skreq->sg_byte_count);
-
-               /* Complete resource allocations. */
-               skreq->state = SKD_REQ_STATE_BUSY;
-               skreq->id += SKD_ID_INCR;
-
-               skmsg->length += sizeof(struct skd_scsi_request);
-               fmh->num_protocol_cmds_coalesced++;
-
-               /*
-                * Update the active request counts.
-                * Capture the timeout timestamp.
-                */
-               skreq->timeout_stamp = atomic_read(&skdev->timeout_stamp);
-               timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
-               atomic_inc(&skdev->timeout_slot[timo_slot]);
-               atomic_inc(&skdev->in_flight);
-               dev_dbg(&skdev->pdev->dev, "req=0x%x busy=%d\n", skreq->id,
-                       atomic_read(&skdev->in_flight));
-
-               /*
-                * If the FIT msg buffer is full send it.
-                */
-               if (fmh->num_protocol_cmds_coalesced >= skd_max_req_per_msg) {
-                       skd_send_fitmsg(skdev, skmsg);
-                       skmsg = NULL;
-                       fmh = NULL;
-               }
+               skd_process_request(req);
        }
 
        /* If the FIT msg buffer is not empty send what we got. */
-       if (skmsg) {
+       if (skdev->skmsg) {
+               struct fit_msg_hdr *fmh = &skdev->skmsg->msg_buf->fmh;
+
                WARN_ON_ONCE(!fmh->num_protocol_cmds_coalesced);
-               skd_send_fitmsg(skdev, skmsg);
-               skmsg = NULL;
-               fmh = NULL;
+               skd_send_fitmsg(skdev, skdev->skmsg);
+               skdev->skmsg = NULL;
        }
 
        /*