| Message ID | 20170922120725.10910-3-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Sep 22, 2017 at 02:07:25PM +0200, Juergen Gross wrote: > 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: Juergen Gross <jgross@suse.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Thanks. > --- > V2: > - always call blk_disconnect() from blk_free() in order to have the > gnttab device node closed (Anthony Perard) > --- > hw/block/xen_disk.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c > index 62506e3167..e431bd89e8 100644 > --- a/hw/block/xen_disk.c > +++ b/hw/block/xen_disk.c > @@ -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); > - } > + 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, > -- > 2.12.3 >
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index 62506e3167..e431bd89e8 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -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); - } + 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,
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: Juergen Gross <jgross@suse.com> --- V2: - always call blk_disconnect() from blk_free() in order to have the gnttab device node closed (Anthony Perard) --- hw/block/xen_disk.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)