diff options
Diffstat (limited to 'drivers/block/xen-blkback/blkback.c')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 4119bcdefd1a..ea158fe0c9a4 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -571,6 +571,7 @@ int xen_blkif_schedule(void *arg) struct xen_blkif *blkif = arg; struct xen_vbd *vbd = &blkif->vbd; unsigned long timeout; + int ret; xen_blkif_get(blkif); @@ -599,8 +600,12 @@ int xen_blkif_schedule(void *arg) blkif->waiting_reqs = 0; smp_mb(); /* clear flag *before* checking for work */ - if (do_block_io_op(blkif)) + ret = do_block_io_op(blkif); + if (ret > 0) blkif->waiting_reqs = 1; + if (ret == -EACCES) + wait_event_interruptible(blkif->shutdown_wq, + kthread_should_stop()); purge_gnt_list: if (blkif->vbd.feature_gnt_persistent && @@ -1009,6 +1014,12 @@ __do_block_io_op(struct xen_blkif *blkif) rp = blk_rings->common.sring->req_prod; rmb(); /* Ensure we see queued requests up to 'rp'. */ + if (RING_REQUEST_PROD_OVERFLOW(&blk_rings->common, rp)) { + rc = blk_rings->common.rsp_prod_pvt; + pr_warn(DRV_PFX "Frontend provided bogus ring requests (%d - %d = %d). Halting ring processing on dev=%04x\n", + rp, rc, rp - rc, blkif->vbd.pdevice); + return -EACCES; + } while (rc != rp) { if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc)) |