2009-10-27 02:17:04

by Patrick Mullaney

[permalink] [raw]
Subject: [PATCH] vbus-enet: fix l4ro pool non-atomic allocations in softirq context

The current code exhibits odd behavior in the guest when receiving L4RO
packets. This was tracked down to the improper allocation of
GFP_KERNEL memory from softirq context


Signed-off-by: Patrick Mullaney <[email protected]>
---

drivers/net/vbus-enet.c | 20 ++++++++++++--------
1 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/net/vbus-enet.c b/drivers/net/vbus-enet.c
index 228c366..6aaee1c 100644
--- a/drivers/net/vbus-enet.c
+++ b/drivers/net/vbus-enet.c
@@ -182,11 +182,11 @@ rxdesc_alloc(struct vbus_enet_priv *priv, struct ioq_ring_desc *desc, size_t len
}

static void
-rx_pageq_refill(struct vbus_enet_priv *priv)
+rx_pageq_refill(struct vbus_enet_priv *priv, gfp_t gfp_mask)
{
struct ioq *ioq = priv->l4ro.pageq.queue;
struct ioq_iterator iter;
- int ret;
+ int ret, added = 0;

if (ioq_full(ioq, ioq_idxtype_inuse))
/* nothing to do if the pageq is already fully populated */
@@ -202,11 +202,14 @@ rx_pageq_refill(struct vbus_enet_priv *priv)
* Now populate each descriptor with an empty page
*/
while (!iter.desc->sown) {
- struct page *page;
+ struct page *page = NULL;
+
+ page = alloc_page(gfp_mask);

- page = alloc_page(GFP_KERNEL);
- BUG_ON(!page);
+ if (!page)
+ break;

+ added = 1;
iter.desc->cookie = (u64)page;
iter.desc->ptr = (u64)__pa(page_address(page));
iter.desc->len = PAGE_SIZE;
@@ -215,7 +218,8 @@ rx_pageq_refill(struct vbus_enet_priv *priv)
BUG_ON(ret < 0);
}

- ioq_signal(ioq, 0);
+ if (added)
+ ioq_signal(ioq, 0);
}

static void
@@ -271,7 +275,7 @@ rx_setup(struct vbus_enet_priv *priv)
}

if (priv->l4ro.available)
- rx_pageq_refill(priv);
+ rx_pageq_refill(priv, GFP_KERNEL);
}

static void
@@ -602,7 +606,7 @@ vbus_enet_l4ro_import(struct vbus_enet_priv *priv, struct ioq_ring_desc *desc)
struct skb_shared_info *sinfo = skb_shinfo(skb);
int i;

- rx_pageq_refill(priv);
+ rx_pageq_refill(priv, GFP_ATOMIC);

if (!vsg->len)
/*


2009-10-27 21:37:19

by Gregory Haskins

[permalink] [raw]
Subject: Re: [Alacrityvm-devel] [PATCH] vbus-enet: fix l4ro pool non-atomic allocations in softirq context

Patrick Mullaney wrote:
> The current code exhibits odd behavior in the guest when receiving L4RO
> packets. This was tracked down to the improper allocation of
> GFP_KERNEL memory from softirq context
>

Applied, thanks!

-Greg



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