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authorRoger Pau Monne <roger.pau@citrix.com>2013-03-18 17:49:32 +0100
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-03-19 17:50:00 +0100
commitffb1dabd1eb10c76a1e7af62f75a1aaa8d590b5a (patch)
tree4590ae87a8f4ca9bfd3a91dbe1a34abec523b48d
parentxen-blkfront: switch from llist to list (diff)
downloadlinux-ffb1dabd1eb10c76a1e7af62f75a1aaa8d590b5a.tar.xz
linux-ffb1dabd1eb10c76a1e7af62f75a1aaa8d590b5a.zip
xen-blkback: don't store dev_bus_addr
dev_bus_addr returned in the grant ref map operation is the mfn of the passed page, there's no need to store it in the persistent grant entry, since we can always get it provided that we have the page. This reduces the memory overhead of persistent grants in blkback. While at it, rename the 'seg[i].buf' to be 'seg[i].offset' as it makes much more sense - as we use that value in bio_add_page which as the fourth argument expects the offset. We hadn't used the physical address as part of this at all. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: xen-devel@lists.xen.org [v1: s/buf/offset/] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
-rw-r--r--drivers/block/xen-blkback/blkback.c21
-rw-r--r--drivers/block/xen-blkback/common.h1
2 files changed, 6 insertions, 16 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 2cf8381a1c6e..dd5b2fed97e9 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -442,7 +442,7 @@ int xen_blkif_schedule(void *arg)
}
struct seg_buf {
- unsigned long buf;
+ unsigned int offset;
unsigned int nsec;
};
/*
@@ -621,30 +621,21 @@ static int xen_blkbk_map(struct blkif_request *req,
* If this is a new persistent grant
* save the handler
*/
- persistent_gnts[i]->handle = map[j].handle;
- persistent_gnts[i]->dev_bus_addr =
- map[j++].dev_bus_addr;
+ persistent_gnts[i]->handle = map[j++].handle;
}
pending_handle(pending_req, i) =
persistent_gnts[i]->handle;
if (ret)
continue;
-
- seg[i].buf = persistent_gnts[i]->dev_bus_addr |
- (req->u.rw.seg[i].first_sect << 9);
} else {
- pending_handle(pending_req, i) = map[j].handle;
+ pending_handle(pending_req, i) = map[j++].handle;
bitmap_set(pending_req->unmap_seg, i, 1);
- if (ret) {
- j++;
+ if (ret)
continue;
- }
-
- seg[i].buf = map[j++].dev_bus_addr |
- (req->u.rw.seg[i].first_sect << 9);
}
+ seg[i].offset = (req->u.rw.seg[i].first_sect << 9);
}
return ret;
}
@@ -971,7 +962,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
(bio_add_page(bio,
pages[i],
seg[i].nsec << 9,
- seg[i].buf & ~PAGE_MASK) == 0)) {
+ seg[i].offset) == 0)) {
bio = bio_alloc(GFP_KERNEL, nseg-i);
if (unlikely(bio == NULL))
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index da78346487ae..60103e2517ba 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -187,7 +187,6 @@ struct persistent_gnt {
struct page *page;
grant_ref_t gnt;
grant_handle_t handle;
- uint64_t dev_bus_addr;
struct rb_node node;
};