diff options
Diffstat (limited to 'drivers/block/xen-blkback/blkback.c')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index f9099940c272..41fb1a917b17 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -950,6 +950,8 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req, goto unmap; for (n = 0, i = 0; n < nseg; n++) { + uint8_t first_sect, last_sect; + if ((n % SEGS_PER_INDIRECT_FRAME) == 0) { /* Map indirect segments */ if (segments) @@ -957,15 +959,18 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req, segments = kmap_atomic(pages[n/SEGS_PER_INDIRECT_FRAME]->page); } i = n % SEGS_PER_INDIRECT_FRAME; + pending_req->segments[n]->gref = segments[i].gref; - seg[n].nsec = segments[i].last_sect - - segments[i].first_sect + 1; - seg[n].offset = (segments[i].first_sect << 9); - if ((segments[i].last_sect >= (XEN_PAGE_SIZE >> 9)) || - (segments[i].last_sect < segments[i].first_sect)) { + + first_sect = READ_ONCE(segments[i].first_sect); + last_sect = READ_ONCE(segments[i].last_sect); + if (last_sect >= (XEN_PAGE_SIZE >> 9) || last_sect < first_sect) { rc = -EINVAL; goto unmap; } + + seg[n].nsec = last_sect - first_sect + 1; + seg[n].offset = first_sect << 9; preq->nr_sects += seg[n].nsec; } |