From c880a2b200e85b47f2e5f3dd085ab0ad28dc6f69 Mon Sep 17 00:00:00 2001
From: Dmitry Fleytman <dmitry@daynix.com>
Date: Thu, 15 May 2014 09:28:36 +0300
Subject: [PATCH] vmxnet3: Drop memory allocation error handling on RX path
Packet discard logic on RX path is incorrect because
it doesn't take into account that incoming packet may be spread
over a few rings.
At the same time discard logic is called in case of newbuf() failure
only and our newbuf() never fails since we have no memory allocation
errors, so discard logic may be safely dropped and this is an
excellent fix for the original problem.
Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
---
drivers/vmxnet3.cc | 48 +++++-----------------------------------------
drivers/vmxnet3.hh | 3 +--
2 files changed, 6 insertions(+), 45 deletions(-)
diff --git a/drivers/vmxnet3.cc b/drivers/vmxnet3.cc
index eab0679a7..97122603e 100644
--- a/drivers/vmxnet3.cc
+++ b/drivers/vmxnet3.cc
@@ -224,9 +224,7 @@ void vmxnet3_rxqueue::init()
rxr.clear_descs();
for (unsigned idx = 0; idx < rxr.get_desc_num(); idx++) {
- auto error = newbuf(i);
- if (error)
- throw std::runtime_error("buf allocation failed");
+ newbuf(i);
}
}
@@ -244,29 +242,7 @@ void vmxnet3_rxqueue::discard(int rid, int idx)
rxr.increment_fill();
}
-void vmxnet3_rxqueue::discard_chain(int rid)
-{
- while (1) {
- auto &rxc = comp_ring;
- auto rxcd = rxc.get_desc(rxc.next);
- if (rxcd->layout->gen != rxc.gen)
- break;
- rmb();
-
- if (++rxc.next == rxc.get_desc_num()) {
- rxc.next = 0;
- rxc.gen ^= 1;
- }
-
- auto idx = rxcd->layout->rxd_idx;
- auto eof = rxcd->layout->eop;
- discard(rid, idx);
- if (eof)
- break;
- }
-}
-
-int vmxnet3_rxqueue::newbuf(int rid)
+void vmxnet3_rxqueue::newbuf(int rid)
{
auto &rxr = cmd_rings[rid];
auto idx = rxr.fill;
@@ -285,7 +261,7 @@ int vmxnet3_rxqueue::newbuf(int rid)
auto m = m_getjcl(M_NOWAIT, MT_DATA, flags, clsize);
if (m == NULL) {
panic("mbuf allocation failed");
- return -1;
+ return;
}
if (btype == vmxnet3::VMXNET3_BTYPE_HEAD) {
m->m_hdr.mh_len = m->M_dat.MH.MH_pkthdr.len = clsize;
@@ -301,7 +277,6 @@ int vmxnet3_rxqueue::newbuf(int rid)
rxd->layout->gen = rxr.gen;
rxr.increment_fill();
- return 0;
}
@@ -780,12 +755,7 @@ void vmxnet3::rxq_eof(vmxnet3_rxqueue &rxq)
goto next;
}
- if (rxq.newbuf(rid) != 0) {
- rxq.discard(rid, idx);
- if (!rxcd->layout->eop)
- rxq.discard_chain(rid);
- goto next;
- }
+ rxq.newbuf(rid);
m->M_dat.MH.MH_pkthdr.len = length;
m->M_dat.MH.MH_pkthdr.rcvif = _ifn;
@@ -796,15 +766,7 @@ void vmxnet3::rxq_eof(vmxnet3_rxqueue &rxq)
assert(rxd->layout->btype == VMXNET3_BTYPE_BODY);
assert(rxq.m_currpkt_head != nullptr);
- if (rxq.newbuf(rid) != 0) {
- rxq.discard(rid, idx);
- if (!rxcd->layout->eop)
- rxq.discard_chain(rid);
- m_freem(rxq.m_currpkt_head);
- _rxq_stats.rx_drops++;
- rxq.m_currpkt_head = rxq.m_currpkt_tail = nullptr;
- goto next;
- }
+ rxq.newbuf(rid);
m->m_hdr.mh_len = length;
rxq.m_currpkt_head->M_dat.MH.MH_pkthdr.len += length;
diff --git a/drivers/vmxnet3.hh b/drivers/vmxnet3.hh
index e37b0f792..18a020b59 100644
--- a/drivers/vmxnet3.hh
+++ b/drivers/vmxnet3.hh
@@ -67,8 +67,7 @@ public:
void init();
void set_intr_idx(unsigned idx) { layout->intr_idx = static_cast<u8>(idx); }
void discard(int rid, int idx);
- void discard_chain(int rid);
- int newbuf(int rid);
+ void newbuf(int rid);
typedef vmxnet3_ring<vmxnet3_rx_desc, VMXNET3_MAX_RX_NDESC> cmdRingT;
typedef vmxnet3_ring<vmxnet3_rx_compdesc, VMXNET3_MAX_RX_NCOMPDESC> compRingT;
--
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