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Date: Fri, 16 Nov 2007 11:22:05 -0800
From: Divy Le Ray <divy@...lsio.com>
To: jeff@...zik.org
Cc: davem@...emloft.net, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, swise@...ngridcomputing.com,
wenxiong@...ibm.com
Subject: [PATCH 6/9] cxgb3 - fix interaction with pktgen
From: Divy Le Ray <divy@...lsio.com>
Do not use skb->cb to stash unmap info,
save the info to the descriptor state.
Signed-off-by: Divy Le Ray <divy@...lsio.com>
---
drivers/net/cxgb3/sge.c | 82 +++++++++++++++++++++++------------------------
1 files changed, 40 insertions(+), 42 deletions(-)
diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index c15e43a..7b13d8a 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -91,6 +91,10 @@ struct rx_desc {
struct tx_sw_desc { /* SW state per Tx descriptor */
struct sk_buff *skb;
+ u8 eop; /* set if last descriptor for packet */
+ u8 addr_idx; /* buffer index of first SGL entry in descriptor */
+ u8 fragidx; /* first page fragment associated with descriptor */
+ s8 sflit; /* start flit of first SGL entry in descriptor */
};
struct rx_sw_desc { /* SW state per Rx descriptor */
@@ -109,13 +113,6 @@ struct rsp_desc { /* response queue descriptor */
u8 intr_gen;
};
-struct unmap_info { /* packet unmapping info, overlays skb->cb */
- int sflit; /* start flit of first SGL entry in Tx descriptor */
- u16 fragidx; /* first page fragment in current Tx descriptor */
- u16 addr_idx; /* buffer index of first SGL entry in descriptor */
- u32 len; /* mapped length of skb main body */
-};
-
/*
* Holds unmapping information for Tx packets that need deferred unmapping.
* This structure lives at skb->head and must be allocated by callers.
@@ -209,32 +206,36 @@ static inline int need_skb_unmap(void)
*
* Unmap the main body of an sk_buff and its page fragments, if any.
* Because of the fairly complicated structure of our SGLs and the desire
- * to conserve space for metadata, we keep the information necessary to
- * unmap an sk_buff partly in the sk_buff itself (in its cb), and partly
- * in the Tx descriptors (the physical addresses of the various data
- * buffers). The send functions initialize the state in skb->cb so we
- * can unmap the buffers held in the first Tx descriptor here, and we
- * have enough information at this point to update the state for the next
- * Tx descriptor.
+ * to conserve space for metadata, the information necessary to unmap an
+ * sk_buff is spread across the sk_buff itself (buffer lengths), the HW Tx
+ * descriptors (the physical addresses of the various data buffers), and
+ * the SW descriptor state (assorted indices). The send functions
+ * initialize the indices for the first packet descriptor so we can unmap
+ * the buffers held in the first Tx descriptor here, and we have enough
+ * information at this point to set the state for the next Tx descriptor.
+ *
+ * Note that it is possible to clean up the first descriptor of a packet
+ * before the send routines have written the next descriptors, but this
+ * race does not cause any problem. We just end up writing the unmapping
+ * info for the descriptor first.
*/
static inline void unmap_skb(struct sk_buff *skb, struct sge_txq *q,
unsigned int cidx, struct pci_dev *pdev)
{
const struct sg_ent *sgp;
- struct unmap_info *ui = (struct unmap_info *)skb->cb;
- int nfrags, frag_idx, curflit, j = ui->addr_idx;
+ struct tx_sw_desc *d = &q->sdesc[cidx];
+ int nfrags, frag_idx, curflit, j = d->addr_idx;
- sgp = (struct sg_ent *)&q->desc[cidx].flit[ui->sflit];
+ sgp = (struct sg_ent *)&q->desc[cidx].flit[d->sflit];
+ frag_idx = d->fragidx;
- if (ui->len) {
- pci_unmap_single(pdev, be64_to_cpu(sgp->addr[0]), ui->len,
- PCI_DMA_TODEVICE);
- ui->len = 0; /* so we know for next descriptor for this skb */
+ if (frag_idx == 0 && skb_headlen(skb)) {
+ pci_unmap_single(pdev, be64_to_cpu(sgp->addr[0]),
+ skb_headlen(skb), PCI_DMA_TODEVICE);
j = 1;
}
- frag_idx = ui->fragidx;
- curflit = ui->sflit + 1 + j;
+ curflit = d->sflit + 1 + j;
nfrags = skb_shinfo(skb)->nr_frags;
while (frag_idx < nfrags && curflit < WR_FLITS) {
@@ -250,10 +251,11 @@ static inline void unmap_skb(struct sk_buff *skb, struct sge_txq *q,
frag_idx++;
}
- if (frag_idx < nfrags) { /* SGL continues into next Tx descriptor */
- ui->fragidx = frag_idx;
- ui->addr_idx = j;
- ui->sflit = curflit - WR_FLITS - j; /* sflit can be -1 */
+ if (frag_idx < nfrags) { /* SGL continues into next Tx descriptor */
+ d = cidx + 1 == q->size ? q->sdesc : d + 1;
+ d->fragidx = frag_idx;
+ d->addr_idx = j;
+ d->sflit = curflit - WR_FLITS - j; /* sflit can be -1 */
}
}
@@ -281,7 +283,7 @@ static void free_tx_desc(struct adapter *adapter, struct sge_txq *q,
if (d->skb) { /* an SGL is present */
if (need_unmap)
unmap_skb(d->skb, q, cidx, pdev);
- if (d->skb->priority == cidx)
+ if (d->eop)
kfree_skb(d->skb);
}
++d;
@@ -912,15 +914,13 @@ static void write_wr_hdr_sgl(unsigned int ndesc, struct sk_buff *skb,
sd->skb = skb;
if (need_skb_unmap()) {
- struct unmap_info *ui = (struct unmap_info *)skb->cb;
-
- ui->fragidx = 0;
- ui->addr_idx = 0;
- ui->sflit = flits;
+ sd->fragidx = 0;
+ sd->addr_idx = 0;
+ sd->sflit = flits;
}
if (likely(ndesc == 1)) {
- skb->priority = pidx;
+ sd->eop = 1;
wrp->wr_hi = htonl(F_WR_SOP | F_WR_EOP | V_WR_DATATYPE(1) |
V_WR_SGLSFLT(flits)) | wr_hi;
wmb();
@@ -948,6 +948,7 @@ static void write_wr_hdr_sgl(unsigned int ndesc, struct sk_buff *skb,
fp += avail;
d++;
+ sd->eop = 0;
sd++;
if (++pidx == q->size) {
pidx = 0;
@@ -966,7 +967,7 @@ static void write_wr_hdr_sgl(unsigned int ndesc, struct sk_buff *skb,
wr_gen2(d, gen);
flits = 1;
}
- skb->priority = pidx;
+ sd->eop = 1;
wrp->wr_hi |= htonl(F_WR_EOP);
wmb();
wp->wr_lo = htonl(V_WR_LEN(WR_FLITS) | V_WR_GEN(ogen)) | wr_lo;
@@ -1051,8 +1052,6 @@ 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 = make_sgl(skb, sgp, skb->data, skb_headlen(skb), adap->pdev);
- if (need_skb_unmap())
- ((struct unmap_info *)skb->cb)->len = skb_headlen(skb);
write_wr_hdr_sgl(ndesc, skb, d, pidx, q, sgl, flits, sgl_flits, gen,
htonl(V_WR_OP(FW_WROPCODE_TUNNEL_TX_PKT) | compl),
@@ -1380,13 +1379,14 @@ static void deferred_unmap_destructor(struct sk_buff *skb)
const dma_addr_t *p;
const struct skb_shared_info *si;
const struct deferred_unmap_info *dui;
- const struct unmap_info *ui = (struct unmap_info *)skb->cb;
dui = (struct deferred_unmap_info *)skb->head;
p = dui->addr;
- if (ui->len)
- pci_unmap_single(dui->pdev, *p++, ui->len, PCI_DMA_TODEVICE);
+ if (skb->tail - skb->transport_header)
+ pci_unmap_single(dui->pdev, *p++,
+ skb->tail - skb->transport_header,
+ PCI_DMA_TODEVICE);
si = skb_shinfo(skb);
for (i = 0; i < si->nr_frags; i++)
@@ -1451,8 +1451,6 @@ static void write_ofld_wr(struct adapter *adap, struct sk_buff *skb,
if (need_skb_unmap()) {
setup_deferred_unmapping(skb, adap->pdev, sgp, sgl_flits);
skb->destructor = deferred_unmap_destructor;
- ((struct unmap_info *)skb->cb)->len = (skb->tail -
- skb->transport_header);
}
write_wr_hdr_sgl(ndesc, skb, d, pidx, q, sgl, flits, sgl_flits,
-
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