[Xen-devel] [PATCH 5/5] xen-blkfront: remove frame list from blk_shadow

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

We already have the frame (pfn of the grant page) stored inside struct
grant, so there's no need to keep an aditional list of mapped frames
for a specific request. This reduces memory usage in blkfront.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxx
---
 drivers/block/xen-blkfront.c |    6 +-----
 1 files changed, 1 insertions(+), 5 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index c640433..a894f88 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -74,7 +74,6 @@ struct grant {
 struct blk_shadow {
        struct blkif_request req;
        struct request *request;
-       unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
        struct grant *grants_used[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 };
 
@@ -356,7 +355,6 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t 
mode,
 static int blkif_queue_request(struct request *req)
 {
        struct blkfront_info *info = req->rq_disk->private_data;
-       unsigned long buffer_mfn;
        struct blkif_request *ring_req;
        unsigned long id;
        unsigned int fsect, lsect;
@@ -434,7 +432,6 @@ static int blkif_queue_request(struct request *req)
 
                        gnt_list_entry = get_grant(&gref_head, info);
                        ref = gnt_list_entry->gref;
-                       buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
 
                        info->shadow[id].grants_used[i] = gnt_list_entry;
 
@@ -465,7 +462,6 @@ static int blkif_queue_request(struct request *req)
                                kunmap_atomic(shared_data);
                        }
 
-                       info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
                        ring_req->u.rw.seg[i] =
                                        (struct blkif_request_segment) {
                                                .gref       = ref,
@@ -1268,7 +1264,7 @@ static int blkif_recover(struct blkfront_info *info)
                                gnttab_grant_foreign_access_ref(
                                        req->u.rw.seg[j].gref,
                                        info->xbdev->otherend_id,
-                                       
pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]),
+                                       pfn_to_mfn(copy[i].grants_used[j]->pfn),
                                        0);
                }
                info->shadow[req->u.rw.id].req = *req;
-- 
1.7.7.5 (Apple Git-26)


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