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@citrix.com>
Cc: <konrad.wilk@oracle.com>
Cc: <linux-kernel@vger.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)
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@citrix.com> > Cc: <konrad.wilk@oracle.com> > Cc: <linux-kernel@vger.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@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
On 02/11/12 18:05, Konrad Rzeszutek Wilk wrote:> 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@citrix.com> >> Cc: <konrad.wilk@oracle.com> >> Cc: <linux-kernel@vger.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?In the previous patch I relied on handle being 0 when not set (that''s why I was using kzalloc), but this was wrong (0 is a valid handle), so now I explicitly initialize it to BLKBACK_INVALID_HANDLE. I replaced the kzalloc with kmalloc because it should be faster, and there''s no need to zero it anymore.> >> 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@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ >>
Possibly Parallel Threads
- [PATCH] Persistent grant maps for xen blk drivers
- [PATCH RFC 09/12] xen-blkback: move pending handles list from blkbk to pending_req
- [RFC v1 3/5] VBD: enlarge max segment per request in blkfront
- [PATCH v3 1/2] xen: enter/exit lazy_mmu_mode around m2p_override calls
- [RFC v1 5/5] VBD: enlarge max segment per request in blkfront