--- /dev/null
+From cea27eb2a202959783f81254c48c250ddd80e129 Mon Sep 17 00:00:00 2001
+From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
+Date: Wed, 3 Jul 2013 15:02:40 -0700
+Subject: mm/memory-hotplug: fix lowmem count overflow when offline pages
+
+From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
+
+commit cea27eb2a202959783f81254c48c250ddd80e129 upstream.
+
+The logic for the memory-remove code fails to correctly account the
+Total High Memory when a memory block which contains High Memory is
+offlined as shown in the example below. The following patch fixes it.
+
+Before logic memory remove:
+
+MemTotal: 7603740 kB
+MemFree: 6329612 kB
+Buffers: 94352 kB
+Cached: 872008 kB
+SwapCached: 0 kB
+Active: 626932 kB
+Inactive: 519216 kB
+Active(anon): 180776 kB
+Inactive(anon): 222944 kB
+Active(file): 446156 kB
+Inactive(file): 296272 kB
+Unevictable: 0 kB
+Mlocked: 0 kB
+HighTotal: 7294672 kB
+HighFree: 5704696 kB
+LowTotal: 309068 kB
+LowFree: 624916 kB
+
+After logic memory remove:
+
+MemTotal: 7079452 kB
+MemFree: 5805976 kB
+Buffers: 94372 kB
+Cached: 872000 kB
+SwapCached: 0 kB
+Active: 626936 kB
+Inactive: 519236 kB
+Active(anon): 180780 kB
+Inactive(anon): 222944 kB
+Active(file): 446156 kB
+Inactive(file): 296292 kB
+Unevictable: 0 kB
+Mlocked: 0 kB
+HighTotal: 7294672 kB
+HighFree: 5181024 kB
+LowTotal: 4294752076 kB
+LowFree: 624952 kB
+
+[mhocko@suse.cz: fix CONFIG_HIGHMEM=n build]
+Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
+Reviewed-by: Michal Hocko <mhocko@suse.cz>
+Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
+Cc: David Rientjes <rientjes@google.com>
+Cc: <stable@vger.kernel.org> [2.6.24+]
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Zhouping Liu <zliu@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ mm/page_alloc.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -5737,6 +5737,10 @@ __offline_isolated_pages(unsigned long s
+ zone->free_area[order].nr_free--;
+ __mod_zone_page_state(zone, NR_FREE_PAGES,
+ - (1UL << order));
++#ifdef CONFIG_HIGHMEM
++ if (PageHighMem(page))
++ totalhigh_pages -= 1 << order;
++#endif
+ for (i = 0; i < (1 << order); i++)
+ SetPageReserved((page+i));
+ pfn += (1 << order);
usb-serial-ftdi_sio-add-more-rt-systems-ftdi-devices.patch
livelock-avoidance-in-sget.patch
xen-evtchn-avoid-a-deadlock-when-unbinding-an-event-channel.patch
+virtio-race-1of2.diff
+virtio-race-2of2.diff
+mm-memory-hotplug-fix-lowmem-count-overflow-when-offline-pages.patch
--- /dev/null
+From: Michael S. Tsirkin <mst@redhat.com>
+Subject: virtio: support unlocked queue poll
+
+From: Michael S. Tsirkin <mst@redhat.com>
+
+commit cc229884d3f77ec3b1240e467e0236c3e0647c0c upstream.
+
+This adds a way to check ring empty state after enable_cb outside any
+locks. Will be used by virtio_net.
+
+Note: there's room for more optimization: caller is likely to have a
+memory barrier already, which means we might be able to get rid of a
+barrier here. Deferring this optimization until we do some
+benchmarking.
+
+Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+[wg: Backported to 3.2]
+Signed-off-by: Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+---
+ drivers/virtio/virtio_ring.c | 59 +++++++++++++++++++++++++++++++++++++------
+ include/linux/virtio.h | 4 ++
+ 2 files changed, 55 insertions(+), 8 deletions(-)
+
+--- a/drivers/virtio/virtio_ring.c
++++ b/drivers/virtio/virtio_ring.c
+@@ -359,9 +359,22 @@ void virtqueue_disable_cb(struct virtque
+ }
+ EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
+
+-bool virtqueue_enable_cb(struct virtqueue *_vq)
++/**
++ * virtqueue_enable_cb_prepare - restart callbacks after disable_cb
++ * @vq: the struct virtqueue we're talking about.
++ *
++ * This re-enables callbacks; it returns current queue state
++ * in an opaque unsigned value. This value should be later tested by
++ * virtqueue_poll, to detect a possible race between the driver checking for
++ * more work, and enabling callbacks.
++ *
++ * Caller must ensure we don't call this with other virtqueue
++ * operations at the same time (except where noted).
++ */
++unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq)
+ {
+ struct vring_virtqueue *vq = to_vvq(_vq);
++ u16 last_used_idx;
+
+ START_USE(vq);
+
+@@ -371,15 +384,45 @@ bool virtqueue_enable_cb(struct virtqueu
+ * either clear the flags bit or point the event index at the next
+ * entry. Always do both to keep code simple. */
+ vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
+- vring_used_event(&vq->vring) = vq->last_used_idx;
++ vring_used_event(&vq->vring) = last_used_idx = vq->last_used_idx;
++ END_USE(vq);
++ return last_used_idx;
++}
++EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare);
++
++/**
++ * virtqueue_poll - query pending used buffers
++ * @vq: the struct virtqueue we're talking about.
++ * @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare).
++ *
++ * Returns "true" if there are pending used buffers in the queue.
++ *
++ * This does not need to be serialized.
++ */
++bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx)
++{
++ struct vring_virtqueue *vq = to_vvq(_vq);
++
+ virtio_mb();
+- if (unlikely(more_used(vq))) {
+- END_USE(vq);
+- return false;
+- }
++ return (u16)last_used_idx != vq->vring.used->idx;
++}
++EXPORT_SYMBOL_GPL(virtqueue_poll);
+
+- END_USE(vq);
+- return true;
++/**
++ * virtqueue_enable_cb - restart callbacks after disable_cb.
++ * @vq: the struct virtqueue we're talking about.
++ *
++ * This re-enables callbacks; it returns "false" if there are pending
++ * buffers in the queue, to detect a possible race between the driver
++ * checking for more work, and enabling callbacks.
++ *
++ * Caller must ensure we don't call this with other virtqueue
++ * operations at the same time (except where noted).
++ */
++bool virtqueue_enable_cb(struct virtqueue *_vq)
++{
++ unsigned last_used_idx = virtqueue_enable_cb_prepare(_vq);
++ return !virtqueue_poll(_vq, last_used_idx);
+ }
+ EXPORT_SYMBOL_GPL(virtqueue_enable_cb);
+
+--- a/include/linux/virtio.h
++++ b/include/linux/virtio.h
+@@ -93,6 +93,10 @@ void virtqueue_disable_cb(struct virtque
+
+ bool virtqueue_enable_cb(struct virtqueue *vq);
+
++unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
++
++bool virtqueue_poll(struct virtqueue *vq, unsigned);
++
+ bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
+
+ void *virtqueue_detach_unused_buf(struct virtqueue *vq);
--- /dev/null
+From: Michael S. Tsirkin <mst@redhat.com>
+Subject: virtio_net: fix race in RX VQ processing
+
+From: Michael S. Tsirkin <mst@redhat.com>
+
+commit cbdadbbf0c790f79350a8f36029208944c5487d0 upstream
+
+virtio net called virtqueue_enable_cq on RX path after napi_complete, so
+with NAPI_STATE_SCHED clear - outside the implicit napi lock.
+This violates the requirement to synchronize virtqueue_enable_cq wrt
+virtqueue_add_buf. In particular, used event can move backwards,
+causing us to lose interrupts.
+In a debug build, this can trigger panic within START_USE.
+
+Jason Wang reports that he can trigger the races artificially,
+by adding udelay() in virtqueue_enable_cb() after virtio_mb().
+
+However, we must call napi_complete to clear NAPI_STATE_SCHED before
+polling the virtqueue for used buffers, otherwise napi_schedule_prep in
+a callback will fail, causing us to lose RX events.
+
+To fix, call virtqueue_enable_cb_prepare with NAPI_STATE_SCHED
+set (under napi lock), later call virtqueue_poll with
+NAPI_STATE_SCHED clear (outside the lock).
+
+Reported-by: Jason Wang <jasowang@redhat.com>
+Tested-by: Jason Wang <jasowang@redhat.com>
+Acked-by: Jason Wang <jasowang@redhat.com>
+Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+[wg: Backported to 3.2]
+Signed-off-by: Wolfram Gloger <wmglo@dent.med.uni-muenchen.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+---
+ drivers/net/virtio_net.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+--- a/drivers/net/virtio_net.c
++++ b/drivers/net/virtio_net.c
+@@ -480,7 +480,7 @@ static int virtnet_poll(struct napi_stru
+ {
+ struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
+ void *buf;
+- unsigned int len, received = 0;
++ unsigned int r, len, received = 0;
+
+ again:
+ while (received < budget &&
+@@ -497,8 +497,9 @@ again:
+
+ /* Out of packets? */
+ if (received < budget) {
++ r = virtqueue_enable_cb_prepare(vi->rvq);
+ napi_complete(napi);
+- if (unlikely(!virtqueue_enable_cb(vi->rvq)) &&
++ if (unlikely(virtqueue_poll(vi->rvq, r)) &&
+ napi_schedule_prep(napi)) {
+ virtqueue_disable_cb(vi->rvq);
+ __napi_schedule(napi);
projects / thirdparty / kernel / stable-queue.git / commitdiff
