scsi: bsg: Move the whole request execution into the SCSI/transport handlers

Remove the amount of indirect calls by making the handler responsible for
the entire execution of the request.

Link: https://lore.kernel.org/r/20210729064845.1044147-5-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index fe43f5f..239ebf7 100644 (file)
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -25,32 +25,39 @@ struct bsg_set {
        bsg_timeout_fn          *timeout_fn;
 };
 
-static int bsg_transport_check_proto(struct sg_io_v4 *hdr)
+static int bsg_transport_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,
+               fmode_t mode, unsigned int timeout)
 {
+       struct bsg_job *job;
+       struct request *rq;
+       struct bio *bio;
+       int ret;
+
        if (hdr->protocol != BSG_PROTOCOL_SCSI  ||
            hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT)
                return -EINVAL;
        if (!capable(CAP_SYS_RAWIO))
                return -EPERM;
-       return 0;
-}
 
-static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
-               fmode_t mode)
-{
-       struct bsg_job *job = blk_mq_rq_to_pdu(rq);
-       int ret;
+       rq = blk_get_request(q, hdr->dout_xfer_len ?
+                            REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
+       if (IS_ERR(rq))
+               return PTR_ERR(rq);
+       rq->timeout = timeout;
 
+       job = blk_mq_rq_to_pdu(rq);
        job->request_len = hdr->request_len;
        job->request = memdup_user(uptr64(hdr->request), hdr->request_len);
-       if (IS_ERR(job->request))
-               return PTR_ERR(job->request);
+       if (IS_ERR(job->request)) {
+               ret = PTR_ERR(job->request);
+               goto out_put_request;
+       }
 
        if (hdr->dout_xfer_len && hdr->din_xfer_len) {
                job->bidi_rq = blk_get_request(rq->q, REQ_OP_DRV_IN, 0);
                if (IS_ERR(job->bidi_rq)) {
                        ret = PTR_ERR(job->bidi_rq);
-                       goto out;
+                       goto out_free_job_request;
                }
 
                ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL,
@@ -65,20 +72,19 @@ static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
                job->bidi_bio = NULL;
        }
 
-       return 0;
+       if (hdr->dout_xfer_len) {
+               ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),
+                               hdr->dout_xfer_len, GFP_KERNEL);
+       } else if (hdr->din_xfer_len) {
+               ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->din_xferp),
+                               hdr->din_xfer_len, GFP_KERNEL);
+       }
 
-out_free_bidi_rq:
-       if (job->bidi_rq)
-               blk_put_request(job->bidi_rq);
-out:
-       kfree(job->request);
-       return ret;
-}
+       if (ret)
+               goto out_unmap_bidi_rq;
 
-static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
-{
-       struct bsg_job *job = blk_mq_rq_to_pdu(rq);
-       int ret = 0;
+       bio = rq->bio;
+       blk_execute_rq(NULL, rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));
 
        /*
         * The assignments below don't make much sense, but are kept for
@@ -121,28 +127,20 @@ static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
                hdr->din_resid = 0;
        }
 
-       return ret;
-}
-
-static void bsg_transport_free_rq(struct request *rq)
-{
-       struct bsg_job *job = blk_mq_rq_to_pdu(rq);
-
-       if (job->bidi_rq) {
+       blk_rq_unmap_user(bio);
+out_unmap_bidi_rq:
+       if (job->bidi_rq)
                blk_rq_unmap_user(job->bidi_bio);
+out_free_bidi_rq:
+       if (job->bidi_rq)
                blk_put_request(job->bidi_rq);
-       }
-
+out_free_job_request:
        kfree(job->request);
+out_put_request:
+       blk_put_request(rq);
+       return ret;
 }
 
-static const struct bsg_ops bsg_transport_ops = {
-       .check_proto            = bsg_transport_check_proto,
-       .fill_hdr               = bsg_transport_fill_hdr,
-       .complete_rq            = bsg_transport_complete_rq,
-       .free_rq                = bsg_transport_free_rq,
-};
-
 /**
  * bsg_teardown_job - routine to teardown a bsg job
  * @kref: kref inside bsg_job that is to be torn down
@@ -398,7 +396,7 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
        q->queuedata = dev;
        blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
 
-       bset->bd = bsg_register_queue(q, dev, name, &bsg_transport_ops);
+       bset->bd = bsg_register_queue(q, dev, name, bsg_transport_sg_io_fn);
        if (IS_ERR(bset->bd)) {
                ret = PTR_ERR(bset->bd);
                goto out_cleanup_queue;

diff --git a/block/bsg.c b/block/bsg.c
index 3ba74ee..3510951 100644 (file)
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -22,12 +22,12 @@
 
 struct bsg_device {
        struct request_queue *queue;
-       const struct bsg_ops *ops;
        struct device device;
        struct cdev cdev;
        int max_queue;
        unsigned int timeout;
        unsigned int reserved_size;
+       bsg_sg_io_fn *sg_io_fn;
 };
 
 static inline struct bsg_device *to_bsg_device(struct inode *inode)
@@ -42,63 +42,28 @@ static DEFINE_IDA(bsg_minor_ida);
 static struct class *bsg_class;
 static int bsg_major;
 
-#define uptr64(val) ((void __user *)(uintptr_t)(val))
+static unsigned int bsg_timeout(struct bsg_device *bd, struct sg_io_v4 *hdr)
+{
+       unsigned int timeout = BLK_DEFAULT_SG_TIMEOUT;
+
+       if (hdr->timeout)
+               timeout = msecs_to_jiffies(hdr->timeout);
+       else if (bd->timeout)
+               timeout = bd->timeout;
+
+       return max_t(unsigned int, timeout, BLK_MIN_SG_TIMEOUT);
+}
 
 static int bsg_sg_io(struct bsg_device *bd, fmode_t mode, void __user *uarg)
 {
-       struct request *rq;
-       struct bio *bio;
        struct sg_io_v4 hdr;
        int ret;
 
        if (copy_from_user(&hdr, uarg, sizeof(hdr)))
                return -EFAULT;
-
        if (hdr.guard != 'Q')
                return -EINVAL;
-       ret = bd->ops->check_proto(&hdr);
-       if (ret)
-               return ret;
-
-       rq = blk_get_request(bd->queue, hdr.dout_xfer_len ?
-                       REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
-       if (IS_ERR(rq))
-               return PTR_ERR(rq);
-
-       ret = bd->ops->fill_hdr(rq, &hdr, mode);
-       if (ret) {
-               blk_put_request(rq);
-               return ret;
-       }
-
-       rq->timeout = msecs_to_jiffies(hdr.timeout);
-       if (!rq->timeout)
-               rq->timeout = bd->timeout;
-       if (!rq->timeout)
-               rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
-       if (rq->timeout < BLK_MIN_SG_TIMEOUT)
-               rq->timeout = BLK_MIN_SG_TIMEOUT;
-
-       if (hdr.dout_xfer_len) {
-               ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr.dout_xferp),
-                               hdr.dout_xfer_len, GFP_KERNEL);
-       } else if (hdr.din_xfer_len) {
-               ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr.din_xferp),
-                               hdr.din_xfer_len, GFP_KERNEL);
-       }
-
-       if (ret)
-               goto out_free_rq;
-
-       bio = rq->bio;
-
-       blk_execute_rq(NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));
-       ret = bd->ops->complete_rq(rq, &hdr);
-       blk_rq_unmap_user(bio);
-
-out_free_rq:
-       bd->ops->free_rq(rq);
-       blk_put_request(rq);
+       ret = bd->sg_io_fn(bd->queue, &hdr, mode, bsg_timeout(bd, &hdr));
        if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
                return -EFAULT;
        return ret;
@@ -211,8 +176,7 @@ void bsg_unregister_queue(struct bsg_device *bd)
 EXPORT_SYMBOL_GPL(bsg_unregister_queue);
 
 struct bsg_device *bsg_register_queue(struct request_queue *q,
-               struct device *parent, const char *name,
-               const struct bsg_ops *ops)
+               struct device *parent, const char *name, bsg_sg_io_fn *sg_io_fn)
 {
        struct bsg_device *bd;
        int ret;
@@ -223,7 +187,7 @@ struct bsg_device *bsg_register_queue(struct request_queue *q,
        bd->max_queue = BSG_DEFAULT_CMDS;
        bd->reserved_size = INT_MAX;
        bd->queue = q;
-       bd->ops = ops;
+       bd->sg_io_fn = sg_io_fn;
 
        ret = ida_simple_get(&bsg_minor_ida, 0, BSG_MAX_DEVS, GFP_KERNEL);
        if (ret < 0) {

diff --git a/drivers/scsi/scsi_bsg.c b/drivers/scsi/scsi_bsg.c
index c0d41c4..d13a67b 100644 (file)
--- a/drivers/scsi/scsi_bsg.c
+++ b/drivers/scsi/scsi_bsg.c
@@ -9,42 +9,57 @@
 
 #define uptr64(val) ((void __user *)(uintptr_t)(val))
 
-static int scsi_bsg_check_proto(struct sg_io_v4 *hdr)
+static int scsi_bsg_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,
+               fmode_t mode, unsigned int timeout)
 {
+       struct scsi_request *sreq;
+       struct request *rq;
+       struct bio *bio;
+       int ret;
+
        if (hdr->protocol != BSG_PROTOCOL_SCSI  ||
            hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
                return -EINVAL;
-       return 0;
-}
-
-static int scsi_bsg_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
-               fmode_t mode)
-{
-       struct scsi_request *sreq = scsi_req(rq);
-
        if (hdr->dout_xfer_len && hdr->din_xfer_len) {
                pr_warn_once("BIDI support in bsg has been removed.\n");
                return -EOPNOTSUPP;
        }
 
+       rq = blk_get_request(q, hdr->dout_xfer_len ?
+                            REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
+       if (IS_ERR(rq))
+               return PTR_ERR(rq);
+       rq->timeout = timeout;
+
+       ret = -ENOMEM;
+       sreq = scsi_req(rq);
        sreq->cmd_len = hdr->request_len;
        if (sreq->cmd_len > BLK_MAX_CDB) {
                sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
                if (!sreq->cmd)
-                       return -ENOMEM;
+                       goto out_put_request;
        }
 
+       ret = -EFAULT;
        if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
-               return -EFAULT;
+               goto out_free_cmd;
+       ret = -EPERM;
        if (!scsi_cmd_allowed(sreq->cmd, mode))
-               return -EPERM;
-       return 0;
-}
+               goto out_free_cmd;
 
-static int scsi_bsg_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
-{
-       struct scsi_request *sreq = scsi_req(rq);
-       int ret = 0;
+       if (hdr->dout_xfer_len) {
+               ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),
+                               hdr->dout_xfer_len, GFP_KERNEL);
+       } else if (hdr->din_xfer_len) {
+               ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->din_xferp),
+                               hdr->din_xfer_len, GFP_KERNEL);
+       }
+
+       if (ret)
+               goto out_free_cmd;
+
+       bio = rq->bio;
+       blk_execute_rq(NULL, rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));
 
        /*
         * fill in all the output members
@@ -74,23 +89,17 @@ static int scsi_bsg_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
        else
                hdr->dout_resid = sreq->resid_len;
 
-       return ret;
-}
+       blk_rq_unmap_user(bio);
 
-static void scsi_bsg_free_rq(struct request *rq)
-{
+out_free_cmd:
        scsi_req_free_cmd(scsi_req(rq));
+out_put_request:
+       blk_put_request(rq);
+       return ret;
 }
 
-static const struct bsg_ops scsi_bsg_ops = {
-       .check_proto            = scsi_bsg_check_proto,
-       .fill_hdr               = scsi_bsg_fill_hdr,
-       .complete_rq            = scsi_bsg_complete_rq,
-       .free_rq                = scsi_bsg_free_rq,
-};
-
 struct bsg_device *scsi_bsg_register_queue(struct scsi_device *sdev)
 {
        return bsg_register_queue(sdev->request_queue, &sdev->sdev_gendev,
-                                 dev_name(&sdev->sdev_gendev), &scsi_bsg_ops);
+                       dev_name(&sdev->sdev_gendev), scsi_bsg_sg_io_fn);
 }

diff --git a/include/linux/bsg.h b/include/linux/bsg.h
index fa21f79..1ac81c8 100644 (file)
--- a/include/linux/bsg.h
+++ b/include/linux/bsg.h
@@ -6,20 +6,14 @@
 
 struct bsg_device;
 struct device;
-struct request;
 struct request_queue;
 
-struct bsg_ops {
-       int     (*check_proto)(struct sg_io_v4 *hdr);
-       int     (*fill_hdr)(struct request *rq, struct sg_io_v4 *hdr,
-                               fmode_t mode);
-       int     (*complete_rq)(struct request *rq, struct sg_io_v4 *hdr);
-       void    (*free_rq)(struct request *rq);
-};
+typedef int (bsg_sg_io_fn)(struct request_queue *, struct sg_io_v4 *hdr,
+               fmode_t mode, unsigned int timeout);
 
 struct bsg_device *bsg_register_queue(struct request_queue *q,
                struct device *parent, const char *name,
-               const struct bsg_ops *ops);
+               bsg_sg_io_fn *sg_io_fn);
 void bsg_unregister_queue(struct bsg_device *bcd);
 
 #endif /* _LINUX_BSG_H */