rds: re-entry of rds_ib_xmit/rds_iw_xmit
The BUG_ON at line 452/453 is triggered in function rds_send_xmit.
441 while (ret) {
442 tmp = min_t(int, ret, sg->length -
443 conn->c_xmit_data_off);
444 conn->c_xmit_data_off += tmp;
445 ret -= tmp;
446 if (conn->c_xmit_data_off == sg->length) {
447 conn->c_xmit_data_off = 0;
448 sg++;
449 conn->c_xmit_sg++;
450 if (ret != 0 && conn->c_xmit_sg == rm->data.op_nents)
451 printk(KERN_ERR "conn %p rm %p sg %p ret %d\n", conn, rm, sg, ret);
452 BUG_ON(ret != 0 &&
453 conn->c_xmit_sg == rm->data.op_nents);
454 }
455 }
it is complaining the total sent length is bigger that we want to send.
rds_ib_xmit() is wrong for the second entry for the same rds_message returning
wrong value.
the sg and off passed by rds_send_xmit to rds_ib_xmit is based on
scatterlist.offset/length, but the rds_ib_xmit action is based on
scatterlist.dma_address/dma_length. in case dma_length is larger than length
there is problem. for the 2nd and later entries of rds_ib_xmit for same
rds_message, at least one of the following two is wrong:
1) the scatterlist to start with, the choosen one can far beyond the correct
one.
2) the offset to start with within the scatterlist.
fix:
add op_dmasg and op_dmaoff to rm_data_op structure indicating the scatterlist
and offset within the it to start with for rds_ib_xmit respectively. op_dmasg
and op_dmaoff are initialized to zero when doing dma mapping for the first see
of the message and are changed when filling send slots.
the same applies to rds_iw_xmit too.
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/net/rds/iw_send.c b/net/rds/iw_send.c
index 1383478..334fe98 100644
--- a/net/rds/iw_send.c
+++ b/net/rds/iw_send.c
@@ -581,6 +581,8 @@
ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs;
ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes;
rds_message_addref(rm);
+ rm->data.op_dmasg = 0;
+ rm->data.op_dmaoff = 0;
ic->i_rm = rm;
/* Finalize the header */
@@ -622,7 +624,7 @@
send = &ic->i_sends[pos];
first = send;
prev = NULL;
- scat = &rm->data.op_sg[sg];
+ scat = &rm->data.op_sg[rm->data.op_dmasg];
sent = 0;
i = 0;
@@ -656,10 +658,11 @@
send = &ic->i_sends[pos];
- len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off);
+ len = min(RDS_FRAG_SIZE,
+ ib_sg_dma_len(dev, scat) - rm->data.op_dmaoff);
rds_iw_xmit_populate_wr(ic, send, pos,
- ib_sg_dma_address(dev, scat) + off, len,
- send_flags);
+ ib_sg_dma_address(dev, scat) + rm->data.op_dmaoff, len,
+ send_flags);
/*
* We want to delay signaling completions just enough to get
@@ -687,10 +690,11 @@
&send->s_wr, send->s_wr.num_sge, send->s_wr.next);
sent += len;
- off += len;
- if (off == ib_sg_dma_len(dev, scat)) {
+ rm->data.op_dmaoff += len;
+ if (rm->data.op_dmaoff == ib_sg_dma_len(dev, scat)) {
scat++;
- off = 0;
+ rm->data.op_dmaoff = 0;
+ rm->data.op_dmasg++;
}
add_header: