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xprtrdma: Byte-align FRWR registration

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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 <sagig@mellanox.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com>
Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com>
Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2015-03-30 14:34:02 -04:00 committed by Anna Schumaker
parent e23779451e
commit 805272406a
1 changed files with 4 additions and 8 deletions
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12
net/sunrpc/xprtrdma/verbs.c
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@ -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);