Commit 976eba1c authored by Paul Durrant's avatar Paul Durrant Committed by Stefano Stabellini
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xen-disk: only advertize feature-persistent if grant copy is not available 



If grant copy is available then it will always be used in preference to
persistent maps. In this case feature-persistent should not be advertized
to the frontend, otherwise it may needlessly copy data into persistently
granted buffers.

Signed-off-by: default avatarPaul Durrant <paul.durrant@citrix.com>
Signed-off-by: default avatarStefano Stabellini <sstabellini@kernel.org>
Reviewed-by: default avatarStefano Stabellini <sstabellini@kernel.org>
parent b0ac694f

hw/block/xen_disk.c

+8 −7
Original line number Diff line number Diff line
@@ -1022,11 +1022,18 @@ static int blk_init(struct XenDevice *xendev) 


    blkdev->file_blk  = BLOCK_SIZE;



    blkdev->feature_grant_copy =

                (xengnttab_grant_copy(blkdev->xendev.gnttabdev, 0, NULL) == 0);



    xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n",

                  blkdev->feature_grant_copy ? "enabled" : "disabled");



    /* fill info

     * blk_connect supplies sector-size and sectors

     */

    xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);

    xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1);

    xenstore_write_be_int(&blkdev->xendev, "feature-persistent",

                          !blkdev->feature_grant_copy);

    xenstore_write_be_int(&blkdev->xendev, "info", info);



    blk_parse_discard(blkdev);
@@ -1201,12 +1208,6 @@ static int blk_connect(struct XenDevice *xendev) 


    xen_be_bind_evtchn(&blkdev->xendev);



    blkdev->feature_grant_copy =

                (xengnttab_grant_copy(blkdev->xendev.gnttabdev, 0, NULL) == 0);



    xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n",

                  blkdev->feature_grant_copy ? "enabled" : "disabled");



    xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, "

                  "remote port %d, local port %d\n",

                  blkdev->xendev.protocol, blkdev->ring_ref,