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Date: Fri, 2 Nov 2012 16:43:04 +0100
From: Roger Pau Monne <roger.pau@...rix.com>
To: <xen-devel@...ts.xen.org>
CC: Roger Pau Monne <roger.pau@...rix.com>, <konrad.wilk@...cle.com>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH] xen-blk: 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.
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(
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)
--
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