Commit e38c3e86 authored by Juergen Gross's avatar Juergen Gross Committed by Stefano Stabellini
Browse files

xen: dont try setting max grants multiple times 



Trying to call xengnttab_set_max_grants() with the same file handle
might fail on some kernels, as this operation is allowed only once.

This is a problem for the qdisk backend as blk_connect() can be
called multiple times for a domain, e.g. in case grub-xen is being
used to boot it.

So instead of letting the generic backend code open the gnttab device
do it in blk_connect() and close it again in blk_disconnect.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Acked-by: default avatarAnthony PERARD <anthony.perard@citrix.com>
Signed-off-by: default avatarStefano Stabellini <sstabellini@kernel.org>
parent b5e397a7

hw/block/xen_disk.c

+12 −4
Original line number Diff line number Diff line
@@ -1220,6 +1220,12 @@ static int blk_connect(struct XenDevice *xendev) 
    /* Add on the number needed for the ring pages */

    max_grants += blkdev->nr_ring_ref;



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

    if (blkdev->xendev.gnttabdev == NULL) {

        xen_pv_printf(xendev, 0, "xengnttab_open failed: %s\n",

                      strerror(errno));

        return -1;

    }

    if (xengnttab_set_max_grants(blkdev->xendev.gnttabdev, max_grants)) {

        xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n",

                      strerror(errno));
@@ -1327,6 +1333,11 @@ static void blk_disconnect(struct XenDevice *xendev) 
        }

        blkdev->feature_persistent = false;

    }



    if (blkdev->xendev.gnttabdev) {

        xengnttab_close(blkdev->xendev.gnttabdev);

        blkdev->xendev.gnttabdev = NULL;

    }

}



static int blk_free(struct XenDevice *xendev)
@@ -1334,9 +1345,7 @@ static int blk_free(struct XenDevice *xendev) 
    struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);

    struct ioreq *ioreq;



    if (blkdev->blk || blkdev->sring) {

    blk_disconnect(xendev);

    }



    while (!QLIST_EMPTY(&blkdev->freelist)) {

        ioreq = QLIST_FIRST(&blkdev->freelist);
@@ -1363,7 +1372,6 @@ static void blk_event(struct XenDevice *xendev) 


struct XenDevOps xen_blkdev_ops = {

    .size       = sizeof(struct XenBlkDev),

    .flags      = DEVOPS_FLAG_NEED_GNTDEV,

    .alloc      = blk_alloc,

    .init       = blk_init,

    .initialise    = blk_connect,