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IB/ipath: fix null deref during rdma ops

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The problem was that node A's sending thread, which handles sending RDMA
read response data, would write the trigger word, the last packet would
be sent, node B would send a new RDMA read request, node A's interrupt
handler would initialize s_rdma_sge, then node A's sending thread would
update s_rdma_sge.  This didn't happen very often naturally but was more
frequent with 1 byte RDMA reads.  Rather than adding more locking or
increasing the QP structure size and copying sge data, I modified the
copy routine to update the pointers before writing the trigger word to
avoid the update race.

Signed-off-by: Ralph Campbell <ralphc@pathscale.com>
Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Bryan O'Sullivan 2006-05-23 11:32:37 -07:00 committed by Roland Dreier
parent 41c75a19bf
commit 3977026462
1 changed files with 7 additions and 5 deletions
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12
drivers/infiniband/hw/ipath/ipath_layer.c
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@ -872,12 +872,13 @@ static void copy_io(u32 __iomem *piobuf, struct ipath_sge_state *ss,
update_sge(ss, len);
length -= len;
}
/* Update address before sending packet. */
update_sge(ss, length);
/* must flush early everything before trigger word */
ipath_flush_wc();
__raw_writel(last, piobuf);
/* be sure trigger word is written */
ipath_flush_wc();
update_sge(ss, length);
}
/**
@ -943,17 +944,18 @@ int ipath_verbs_send(struct ipath_devdata *dd, u32 hdrwords,
if (likely(ss->num_sge == 1 && len <= ss->sge.length &&
!((unsigned long)ss->sge.vaddr & (sizeof(u32) - 1)))) {
u32 w;
u32 *addr = (u32 *) ss->sge.vaddr;
/* Update address before sending packet. */
update_sge(ss, len);
/* Need to round up for the last dword in the packet. */
w = (len + 3) >> 2;
__iowrite32_copy(piobuf, ss->sge.vaddr, w - 1);
__iowrite32_copy(piobuf, addr, w - 1);
/* must flush early everything before trigger word */
ipath_flush_wc();
__raw_writel(((u32 *) ss->sge.vaddr)[w - 1],
piobuf + w - 1);
__raw_writel(addr[w - 1], piobuf + w - 1);
/* be sure trigger word is written */
ipath_flush_wc();
update_sge(ss, len);
ret = 0;
goto bail;
}