From d655a9fbc8a51ac8d92db7ff5a599aab17dce3ca Mon Sep 17 00:00:00 2001 From: Wengang Wang Date: Thu, 21 May 2015 13:11:40 +0800 Subject: 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 Signed-off-by: Doug Ledford --- net/rds/rds.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/rds/rds.h') diff --git a/net/rds/rds.h b/net/rds/rds.h index 0d41155a2258..d2c60097ddeb 100644 --- a/net/rds/rds.h +++ b/net/rds/rds.h @@ -363,6 +363,8 @@ struct rds_message { unsigned int op_active:1; unsigned int op_nents; unsigned int op_count; + unsigned int op_dmasg; + unsigned int op_dmaoff; struct scatterlist *op_sg; } data; }; -- cgit v1.2.3