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Revert "cxgb3: Check and handle the dma mapping errors"
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This reverts commit f83331b.

As the tests PPC64 (powernv platform) show, IOMMU pages are leaking
when transferring big amount of small packets (<=64 bytes),
"ping -f" and waiting for 15 seconds is the simplest way to confirm the bug.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Santosh Rastapur <santosh@chelsio.com>
Cc: Jay Fenlason <fenlason@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Divy Le ray <divy@chelsio.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alexey Kardashevskiy authored and David S. Miller committed Aug 15, 2013
1 parent 3da988c commit 728e2cc
Showing 1 changed file with 24 additions and 83 deletions.
107 changes: 24 additions & 83 deletions drivers/net/ethernet/chelsio/cxgb3/sge.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -455,11 +455,6 @@ static int alloc_pg_chunk(struct adapter *adapter, struct sge_fl *q,
q->pg_chunk.offset = 0;
mapping = pci_map_page(adapter->pdev, q->pg_chunk.page,
0, q->alloc_size, PCI_DMA_FROMDEVICE);
if (unlikely(pci_dma_mapping_error(adapter->pdev, mapping))) {
__free_pages(q->pg_chunk.page, order);
q->pg_chunk.page = NULL;
return -EIO;
}
q->pg_chunk.mapping = mapping;
}
sd->pg_chunk = q->pg_chunk;
Expand Down Expand Up @@ -954,75 +949,40 @@ static inline unsigned int calc_tx_descs(const struct sk_buff *skb)
return flits_to_desc(flits);
}


/* map_skb - map a packet main body and its page fragments
* @pdev: the PCI device
* @skb: the packet
* @addr: placeholder to save the mapped addresses
*
* map the main body of an sk_buff and its page fragments, if any.
*/
static int map_skb(struct pci_dev *pdev, const struct sk_buff *skb,
dma_addr_t *addr)
{
const skb_frag_t *fp, *end;
const struct skb_shared_info *si;

*addr = pci_map_single(pdev, skb->data, skb_headlen(skb),
PCI_DMA_TODEVICE);
if (pci_dma_mapping_error(pdev, *addr))
goto out_err;

si = skb_shinfo(skb);
end = &si->frags[si->nr_frags];

for (fp = si->frags; fp < end; fp++) {
*++addr = skb_frag_dma_map(&pdev->dev, fp, 0, skb_frag_size(fp),
DMA_TO_DEVICE);
if (pci_dma_mapping_error(pdev, *addr))
goto unwind;
}
return 0;

unwind:
while (fp-- > si->frags)
dma_unmap_page(&pdev->dev, *--addr, skb_frag_size(fp),
DMA_TO_DEVICE);

pci_unmap_single(pdev, addr[-1], skb_headlen(skb), PCI_DMA_TODEVICE);
out_err:
return -ENOMEM;
}

/**
* write_sgl - populate a scatter/gather list for a packet
* make_sgl - populate a scatter/gather list for a packet
* @skb: the packet
* @sgp: the SGL to populate
* @start: start address of skb main body data to include in the SGL
* @len: length of skb main body data to include in the SGL
* @addr: the list of the mapped addresses
* @pdev: the PCI device
*
* Copies the scatter/gather list for the buffers that make up a packet
* Generates a scatter/gather list for the buffers that make up a packet
* and returns the SGL size in 8-byte words. The caller must size the SGL
* appropriately.
*/
static inline unsigned int write_sgl(const struct sk_buff *skb,
static inline unsigned int make_sgl(const struct sk_buff *skb,
struct sg_ent *sgp, unsigned char *start,
unsigned int len, const dma_addr_t *addr)
unsigned int len, struct pci_dev *pdev)
{
unsigned int i, j = 0, k = 0, nfrags;
dma_addr_t mapping;
unsigned int i, j = 0, nfrags;

if (len) {
mapping = pci_map_single(pdev, start, len, PCI_DMA_TODEVICE);
sgp->len[0] = cpu_to_be32(len);
sgp->addr[j++] = cpu_to_be64(addr[k++]);
sgp->addr[0] = cpu_to_be64(mapping);
j = 1;
}

nfrags = skb_shinfo(skb)->nr_frags;
for (i = 0; i < nfrags; i++) {
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

mapping = skb_frag_dma_map(&pdev->dev, frag, 0, skb_frag_size(frag),
DMA_TO_DEVICE);
sgp->len[j] = cpu_to_be32(skb_frag_size(frag));
sgp->addr[j] = cpu_to_be64(addr[k++]);
sgp->addr[j] = cpu_to_be64(mapping);
j ^= 1;
if (j == 0)
++sgp;
Expand Down Expand Up @@ -1178,7 +1138,7 @@ static void write_tx_pkt_wr(struct adapter *adap, struct sk_buff *skb,
const struct port_info *pi,
unsigned int pidx, unsigned int gen,
struct sge_txq *q, unsigned int ndesc,
unsigned int compl, const dma_addr_t *addr)
unsigned int compl)
{
unsigned int flits, sgl_flits, cntrl, tso_info;
struct sg_ent *sgp, sgl[MAX_SKB_FRAGS / 2 + 1];
Expand Down Expand Up @@ -1236,7 +1196,7 @@ static void write_tx_pkt_wr(struct adapter *adap, struct sk_buff *skb,
}

sgp = ndesc == 1 ? (struct sg_ent *)&d->flit[flits] : sgl;
sgl_flits = write_sgl(skb, sgp, skb->data, skb_headlen(skb), addr);
sgl_flits = make_sgl(skb, sgp, skb->data, skb_headlen(skb), adap->pdev);

write_wr_hdr_sgl(ndesc, skb, d, pidx, q, sgl, flits, sgl_flits, gen,
htonl(V_WR_OP(FW_WROPCODE_TUNNEL_TX_PKT) | compl),
Expand Down Expand Up @@ -1267,7 +1227,6 @@ netdev_tx_t t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
struct netdev_queue *txq;
struct sge_qset *qs;
struct sge_txq *q;
dma_addr_t addr[MAX_SKB_FRAGS + 1];

/*
* The chip min packet length is 9 octets but play safe and reject
Expand Down Expand Up @@ -1296,11 +1255,6 @@ netdev_tx_t t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
return NETDEV_TX_BUSY;
}

if (unlikely(map_skb(adap->pdev, skb, addr) < 0)) {
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}

q->in_use += ndesc;
if (unlikely(credits - ndesc < q->stop_thres)) {
t3_stop_tx_queue(txq, qs, q);
Expand Down Expand Up @@ -1358,7 +1312,7 @@ netdev_tx_t t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
if (likely(!skb_shared(skb)))
skb_orphan(skb);

write_tx_pkt_wr(adap, skb, pi, pidx, gen, q, ndesc, compl, addr);
write_tx_pkt_wr(adap, skb, pi, pidx, gen, q, ndesc, compl);
check_ring_tx_db(adap, q);
return NETDEV_TX_OK;
}
Expand Down Expand Up @@ -1623,8 +1577,7 @@ static void setup_deferred_unmapping(struct sk_buff *skb, struct pci_dev *pdev,
*/
static void write_ofld_wr(struct adapter *adap, struct sk_buff *skb,
struct sge_txq *q, unsigned int pidx,
unsigned int gen, unsigned int ndesc,
const dma_addr_t *addr)
unsigned int gen, unsigned int ndesc)
{
unsigned int sgl_flits, flits;
struct work_request_hdr *from;
Expand All @@ -1645,9 +1598,9 @@ static void write_ofld_wr(struct adapter *adap, struct sk_buff *skb,

flits = skb_transport_offset(skb) / 8;
sgp = ndesc == 1 ? (struct sg_ent *)&d->flit[flits] : sgl;
sgl_flits = write_sgl(skb, sgp, skb_transport_header(skb),
skb_tail_pointer(skb) -
skb_transport_header(skb), addr);
sgl_flits = make_sgl(skb, sgp, skb_transport_header(skb),
skb->tail - skb->transport_header,
adap->pdev);
if (need_skb_unmap()) {
setup_deferred_unmapping(skb, adap->pdev, sgp, sgl_flits);
skb->destructor = deferred_unmap_destructor;
Expand Down Expand Up @@ -1705,11 +1658,6 @@ again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
goto again;
}

if (map_skb(adap->pdev, skb, (dma_addr_t *)skb->head)) {
spin_unlock(&q->lock);
return NET_XMIT_SUCCESS;
}

gen = q->gen;
q->in_use += ndesc;
pidx = q->pidx;
Expand All @@ -1720,7 +1668,7 @@ again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
}
spin_unlock(&q->lock);

write_ofld_wr(adap, skb, q, pidx, gen, ndesc, (dma_addr_t *)skb->head);
write_ofld_wr(adap, skb, q, pidx, gen, ndesc);
check_ring_tx_db(adap, q);
return NET_XMIT_SUCCESS;
}
Expand All @@ -1738,7 +1686,6 @@ static void restart_offloadq(unsigned long data)
struct sge_txq *q = &qs->txq[TXQ_OFLD];
const struct port_info *pi = netdev_priv(qs->netdev);
struct adapter *adap = pi->adapter;
unsigned int written = 0;

spin_lock(&q->lock);
again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
Expand All @@ -1758,23 +1705,18 @@ again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
break;
}

if (map_skb(adap->pdev, skb, (dma_addr_t *)skb->head))
break;

gen = q->gen;
q->in_use += ndesc;
pidx = q->pidx;
q->pidx += ndesc;
written += ndesc;
if (q->pidx >= q->size) {
q->pidx -= q->size;
q->gen ^= 1;
}
__skb_unlink(skb, &q->sendq);
spin_unlock(&q->lock);

write_ofld_wr(adap, skb, q, pidx, gen, ndesc,
(dma_addr_t *)skb->head);
write_ofld_wr(adap, skb, q, pidx, gen, ndesc);
spin_lock(&q->lock);
}
spin_unlock(&q->lock);
Expand All @@ -1784,9 +1726,8 @@ again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
set_bit(TXQ_LAST_PKT_DB, &q->flags);
#endif
wmb();
if (likely(written))
t3_write_reg(adap, A_SG_KDOORBELL,
F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
t3_write_reg(adap, A_SG_KDOORBELL,
F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
}

/**
Expand Down

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