Author: cperciva
Date: Fri Jun 19 22:40:58 2015
New Revision: 284615
URL: https://svnweb.freebsd.org/changeset/base/284615
Log:
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.
Modified:
head/sys/dev/xen/blkfront/blkfront.c
Modified: head/sys/dev/xen/blkfront/blkfront.c
==============================================================================
--- head/sys/dev/xen/blkfront/blkfront.c Fri Jun 19 22:24:58 2015
(r284614)
+++ head/sys/dev/xen/blkfront/blkfront.c Fri Jun 19 22:40:58 2015
(r284615)
@@ -168,7 +168,6 @@ xbd_queue_cb(void *arg, bus_dma_segment_
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_
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_
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_
sg++;
sg_ref++;
segs++;
- nsegs--;
}
if (cm->cm_operation == BLKIF_OP_READ)
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