X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fblock%2Fxen-blkback%2Fblkback.c;fp=drivers%2Fblock%2Fxen-blkback%2Fblkback.c;h=2232b858618f5b6131da99912e549534767b89a9;hb=9371cadbbcc7c00c81753b9727b19fb3bc74d458;hp=85fdd4ba37d4666335c5b5d49936a36de8a14cf2;hpb=79c4d036e08cdcd9403047a37cbc9e37b5ee86b4;p=pandora-kernel.git

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 85fdd4ba37d4..2232b858618f 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -277,6 +277,7 @@ int xen_blkif_schedule(void *arg)
 {
 	struct xen_blkif *blkif = arg;
 	struct xen_vbd *vbd = &blkif->vbd;
+	int ret;
 
 	xen_blkif_get(blkif);
 
@@ -297,8 +298,12 @@ 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());
 
 		if (log_stats && time_after(jiffies, blkif->st_print))
 			print_stats(blkif);
@@ -539,6 +544,12 @@ __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))