From cb5bd4d19b46c220b1ac8462a3da01767dd99488 Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Fri, 2 Nov 2012 16:43:04 +0100 Subject: [PATCH] xen/blkback: persistent-grants fixes This patch contains fixes for persistent grants implementation v2: * handle == 0 is a valid handle, so initialize grants in blkback setting the handle to BLKBACK_INVALID_HANDLE instead of 0. Reported by Konrad Rzeszutek Wilk. * new_map is a boolean, use "true" or "false" instead of 1 and 0. Reported by Konrad Rzeszutek Wilk. * blkfront announces the persistent-grants feature as feature-persistent-grants, use feature-persistent instead which is consistent with blkback and the public Xen headers. * Add a consistency check in blkfront to make sure we don't try to access segments that have not been set. Reported-by: Konrad Rzeszutek Wilk Signed-off-by: Roger Pau Monne [v1: The new_map int->bool had already been changed] Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkback/blkback.c | 9 ++++++--- drivers/block/xen-blkback/xenbus.c | 2 +- drivers/block/xen-blkfront.c | 3 ++- 3 files changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index d7dd5cbdac5f..a05961683efa 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -512,7 +512,7 @@ static int xen_blkbk_map(struct blkif_request *req, * not mapped but we have room for it */ new_map = true; - persistent_gnt = kzalloc( + persistent_gnt = kmalloc( sizeof(struct persistent_gnt), GFP_KERNEL); if (!persistent_gnt) @@ -523,6 +523,7 @@ static int xen_blkbk_map(struct blkif_request *req, return -ENOMEM; } persistent_gnt->gnt = req->u.rw.seg[i].gref; + persistent_gnt->handle = BLKBACK_INVALID_HANDLE; pages_to_gnt[segs_to_map] = persistent_gnt->page; @@ -584,7 +585,8 @@ static int xen_blkbk_map(struct blkif_request *req, */ bitmap_zero(pending_req->unmap_seg, BLKIF_MAX_SEGMENTS_PER_REQUEST); for (i = 0, j = 0; i < nseg; i++) { - if (!persistent_gnts[i] || !persistent_gnts[i]->handle) { + if (!persistent_gnts[i] || + persistent_gnts[i]->handle == BLKBACK_INVALID_HANDLE) { /* This is a newly mapped grant */ BUG_ON(j >= segs_to_map); if (unlikely(map[j].status != 0)) { @@ -601,7 +603,8 @@ static int xen_blkbk_map(struct blkif_request *req, } } if (persistent_gnts[i]) { - if (!persistent_gnts[i]->handle) { + if (persistent_gnts[i]->handle == + BLKBACK_INVALID_HANDLE) { /* * If this is a new persistent grant * save the handler diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index b2250265308a..a03ecbb0044c 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -760,7 +760,7 @@ static int connect_ring(struct backend_info *be) return -1; } err = xenbus_gather(XBT_NIL, dev->otherend, - "feature-persistent-grants", "%u", + "feature-persistent", "%u", &pers_grants, NULL); if (err) pers_grants = 0; diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 911d733d21b6..f1de806b0a63 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -852,6 +852,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, rq_for_each_segment(bvec, s->request, iter) { BUG_ON((bvec->bv_offset + bvec->bv_len) > PAGE_SIZE); i = offset >> PAGE_SHIFT; + BUG_ON(i >= s->req.u.rw.nr_segments); shared_data = kmap_atomic( pfn_to_page(s->grants_used[i]->pfn)); bvec_data = bvec_kmap_irq(bvec, &flags); @@ -1069,7 +1070,7 @@ again: goto abort_transaction; } err = xenbus_printf(xbt, dev->nodename, - "feature-persistent-grants", "%u", 1); + "feature-persistent", "%u", 1); if (err) dev_warn(&dev->dev, "writing persistent grants feature to xenbus"); -- 2.39.5