| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20121102170543.GA1853@konrad-lan.dumpdata.com>
Date: Fri, 2 Nov 2012 13:05:46 -0400
From: Konrad Rzeszutek Wilk <konrad@...nok.org>
To: Roger Pau Monne <roger.pau@...rix.com>
Cc: xen-devel@...ts.xen.org, konrad.wilk@...cle.com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] xen-blk: persistent-grants fixes
On Fri, Nov 02, 2012 at 04:43:04PM +0100, Roger Pau Monne wrote:
> 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.
Looks good.. but
>
> Signed-off-by: Roger Pau Monne <roger.pau@...rix.com>
> Cc: <konrad.wilk@...cle.com>
> Cc: <linux-kernel@...r.kernel.org>
> ---
> drivers/block/xen-blkback/blkback.c | 15 +++++++++------
> drivers/block/xen-blkback/xenbus.c | 2 +-
> drivers/block/xen-blkfront.c | 3 ++-
> 3 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
> index 663d42d..a059616 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -503,7 +503,7 @@ static int xen_blkbk_map(struct blkif_request *req,
> * We are using persistent grants and
> * the grant is already mapped
> */
> - new_map = 0;
> + new_map = false;
> } else if (use_persistent_gnts &&
> blkif->persistent_gnt_c <
> max_mapped_grant_pages(blkif->blk_protocol)) {
> @@ -511,8 +511,8 @@ static int xen_blkbk_map(struct blkif_request *req,
> * We are using persistent grants, the grant is
> * not mapped but we have room for it
> */
> - new_map = 1;
> - persistent_gnt = kzalloc(
> + new_map = true;
> + persistent_gnt = kmalloc(
Why do we want to use kmalloc instead of kzalloc?
> 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;
> @@ -547,7 +548,7 @@ static int xen_blkbk_map(struct blkif_request *req,
> pr_alert(DRV_PFX " domain %u, device %#x is using maximum number of persistent grants\n",
> blkif->domid, blkif->vbd.handle);
> }
> - new_map = 1;
> + new_map = true;
> pages[i] = blkbk->pending_page(pending_req, i);
> addr = vaddr(pending_req, i);
> pages_to_gnt[segs_to_map] =
> @@ -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 b225026..a03ecbb 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 911d733..f1de806 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");
> --
> 1.7.7.5 (Apple Git-26)
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists