bsg: add bidi support

bsg uses the rq->next_rq pointer for a bidi request.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/block/bsg.c b/block/bsg.c
index 5f4abc9..13ecc95 100644 (file)
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -95,6 +95,7 @@ struct bsg_command {
        struct list_head list;
        struct request *rq;
        struct bio *bio;
+       struct bio *bidi_bio;
        int err;
        struct sg_io_v4 hdr;
        struct sg_io_v4 __user *uhdr;
@@ -243,16 +244,6 @@ bsg_validate_sgv4_hdr(request_queue_t *q, struct sg_io_v4 *hdr, int *rw)
        if (hdr->protocol || hdr->subprotocol)
                return -EINVAL;
 
-       /*
-        * looks sane, if no data then it should be fine from our POV
-        */
-       if (!hdr->dout_xfer_len && !hdr->din_xfer_len)
-               return 0;
-
-       /* not supported currently */
-       if (hdr->dout_xfer_len && hdr->din_xfer_len)
-               return -EINVAL;
-
        *rw = hdr->dout_xfer_len ? WRITE : READ;
 
        return 0;
@@ -265,7 +256,7 @@ static struct request *
 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
 {
        request_queue_t *q = bd->queue;
-       struct request *rq;
+       struct request *rq, *next_rq = NULL;
        int ret, rw = 0; /* shut up gcc */
        unsigned int dxfer_len;
        void *dxferp = NULL;
@@ -282,11 +273,30 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
         * map scatter-gather elements seperately and string them to request
         */
        rq = blk_get_request(q, rw, GFP_KERNEL);
+       if (!rq)
+               return ERR_PTR(-ENOMEM);
        ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, test_bit(BSG_F_WRITE_PERM,
                                                       &bd->flags));
-       if (ret) {
-               blk_put_request(rq);
-               return ERR_PTR(ret);
+       if (ret)
+               goto out;
+
+       if (rw == WRITE && hdr->din_xfer_len) {
+               if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
+                       ret = -EOPNOTSUPP;
+                       goto out;
+               }
+
+               next_rq = blk_get_request(q, READ, GFP_KERNEL);
+               if (!next_rq) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               rq->next_rq = next_rq;
+
+               dxferp = (void*)(unsigned long)hdr->din_xferp;
+               ret =  blk_rq_map_user(q, next_rq, dxferp, hdr->din_xfer_len);
+               if (ret)
+                       goto out;
        }
 
        if (hdr->dout_xfer_len) {
@@ -300,14 +310,17 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
 
        if (dxfer_len) {
                ret = blk_rq_map_user(q, rq, dxferp, dxfer_len);
-               if (ret) {
-                       dprintk("failed map at %d\n", ret);
-                       blk_put_request(rq);
-                       rq = ERR_PTR(ret);
-               }
+               if (ret)
+                       goto out;
        }
-
        return rq;
+out:
+       blk_put_request(rq);
+       if (next_rq) {
+               blk_rq_unmap_user(next_rq->bio);
+               blk_put_request(next_rq);
+       }
+       return ERR_PTR(ret);
 }
 
 /*
@@ -346,6 +359,8 @@ static void bsg_add_command(struct bsg_device *bd, request_queue_t *q,
         */
        bc->rq = rq;
        bc->bio = rq->bio;
+       if (rq->next_rq)
+               bc->bidi_bio = rq->next_rq->bio;
        bc->hdr.duration = jiffies;
        spin_lock_irq(&bd->lock);
        list_add_tail(&bc->list, &bd->busy_list);
@@ -402,7 +417,7 @@ static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd)
 }
 
 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
-                                   struct bio *bio)
+                                   struct bio *bio, struct bio *bidi_bio)
 {
        int ret = 0;
 
@@ -431,6 +446,11 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
                        ret = -EFAULT;
        }
 
+       if (rq->next_rq) {
+               blk_rq_unmap_user(bidi_bio);
+               blk_put_request(rq->next_rq);
+       }
+
        blk_rq_unmap_user(bio);
        blk_put_request(rq);
 
@@ -477,7 +497,8 @@ static int bsg_complete_all_commands(struct bsg_device *bd)
                if (IS_ERR(bc))
                        break;
 
-               tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio);
+               tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
+                                               bc->bidi_bio);
                if (!ret)
                        ret = tret;
 
@@ -511,7 +532,8 @@ __bsg_read(char __user *buf, size_t count, struct bsg_device *bd,
                 * after completing the request. so do that here,
                 * bsg_complete_work() cannot do that for us
                 */
-               ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio);
+               ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio,
+                                              bc->bidi_bio);
 
                if (copy_to_user(buf, (char *) &bc->hdr, sizeof(bc->hdr)))
                        ret = -EFAULT;
@@ -868,7 +890,7 @@ bsg_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
        }
        case SG_IO: {
                struct request *rq;
-               struct bio *bio;
+               struct bio *bio, *bidi_bio = NULL;
                struct sg_io_v4 hdr;
 
                if (copy_from_user(&hdr, uarg, sizeof(hdr)))
@@ -879,8 +901,10 @@ bsg_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
                        return PTR_ERR(rq);
 
                bio = rq->bio;
+               if (rq->next_rq)
+                       bidi_bio = rq->next_rq->bio;
                blk_execute_rq(bd->queue, NULL, rq, 0);
-               blk_complete_sgv4_hdr_rq(rq, &hdr, bio);
+               blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
 
                if (copy_to_user(uarg, &hdr, sizeof(hdr)))
                        return -EFAULT;