The RPC/RDMA transport's FRWR registration logic registers whole pages. This means areas in the first and last pages that are not involved in the RDMA I/O are needlessly exposed to the server.
Buffered I/O is typically page-aligned, so not a problem there. But for direct I/O, which can be byte-aligned, and for reply chunks, which are nearly always smaller than a page, the transport could expose memory outside the I/O buffer. FRWR allows byte-aligned memory registration, so let's use it as it was intended. Reported-by: Sagi Grimberg <[email protected]> Signed-off-by: Chuck Lever <[email protected]> Tested-by: Devesh Sharma <[email protected]> Tested-by: Meghana Cheripady <[email protected]> Tested-by: Veeresh U. Kokatnur <[email protected]> --- net/sunrpc/xprtrdma/verbs.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 1aa55b7..60f3317 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1924,23 +1924,19 @@ rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg, offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len)) break; } - dprintk("RPC: %s: Using frmr %p to map %d segments\n", - __func__, mw, i); + dprintk("RPC: %s: Using frmr %p to map %d segments (%d bytes)\n", + __func__, mw, i, len); frmr->fr_state = FRMR_IS_VALID; memset(&fastreg_wr, 0, sizeof(fastreg_wr)); fastreg_wr.wr_id = (unsigned long)(void *)mw; fastreg_wr.opcode = IB_WR_FAST_REG_MR; - fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma; + fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma + pageoff; fastreg_wr.wr.fast_reg.page_list = frmr->fr_pgl; fastreg_wr.wr.fast_reg.page_list_len = page_no; fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT; - fastreg_wr.wr.fast_reg.length = page_no << PAGE_SHIFT; - if (fastreg_wr.wr.fast_reg.length < len) { - rc = -EIO; - goto out_err; - } + fastreg_wr.wr.fast_reg.length = len; /* Bump the key */ key = (u8)(mr->rkey & 0x000000FF); -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
