Minor clean up to xbd_queue_cb:

* nsegs must be at most BLKIF_MAX_SEGMENTS_PER_REQUEST (since we specify
  that limit to bus_dma_tag_create), so KASSERT that rather than silently
  adjusting the request.
* block_segs is now a synonym for nsegs, so garbage collect that variable.
* nsegs is never read during or after the while loop, so remove the dead
  decrement from the loop.

These were all left behind from the pre-r284296 support for a "segment
block" extension.
This commit is contained in:
cperciva 2015-06-19 22:40:58 +00:00
parent 200a3fb372
commit 87997fdb5d

View File

@ -168,7 +168,6 @@ xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
uint64_t fsect, lsect;
int ref;
int op;
int block_segs;
cm = arg;
sc = cm->cm_sc;
@ -180,6 +179,9 @@ xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
return;
}
KASSERT(nsegs <= BLKIF_MAX_SEGMENTS_PER_REQUEST,
("Too many segments in a blkfront I/O"));
/* Fill out a communications ring structure. */
ring_req = RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
sc->xbd_ring.req_prod_pvt++;
@ -190,9 +192,8 @@ xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
ring_req->nr_segments = nsegs;
cm->cm_nseg = nsegs;
block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_REQUEST);
sg = ring_req->seg;
last_block_sg = sg + block_segs;
last_block_sg = sg + nsegs;
sg_ref = cm->cm_sg_refs;
while (sg < last_block_sg) {
@ -227,7 +228,6 @@ xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
sg++;
sg_ref++;
segs++;
nsegs--;
}
if (cm->cm_operation == BLKIF_OP_READ)