On 2/3/2021 11:23 AM, Chuck Lever wrote:
Support for FMR was removed by commit ba69cd122ece ("xprtrdma: Remove support for FMR memory registration") [Dec 2018]. That means the buffer-splitting behavior of rpcrdma_convert_kvec(), added by commit 821c791a0bde ("xprtrdma: Segment head and tail XDR buffers on page boundaries") [Mar 2016], is no longer necessary. FRWR memory registration handles this case with aplomb. Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- net/sunrpc/xprtrdma/rpc_rdma.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index 8f5d0cb68360..832765f3ebba 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -204,9 +204,7 @@ rpcrdma_alloc_sparse_pages(struct xdr_buf *buf) return 0; }-/* Split @vec on page boundaries into SGEs. FMR registers pages, not- * a byte range. Other modes coalesce these SGEs into a single MR - * when they can. +/* Convert @vec to a single SGL element. * * Returns pointer to next available SGE, and bumps the total number * of SGEs consumed. @@ -215,21 +213,12 @@ static struct rpcrdma_mr_seg * rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg, unsigned int *n) { - u32 remaining, page_offset; - char *base; - - base = vec->iov_base; - page_offset = offset_in_page(base); - remaining = vec->iov_len; - while (remaining) { + if (vec->iov_len) {
This is weird. Is it ever possible for a zero-length segment to be passed? If so, it's obviously wrong to return an uninitialized "seg" to the caller. I'd suggest simply asserting that iov_len is != 0. I guess this was an issue in the existing code, but there, it would only trigger if *all* the segs were zero.
seg->mr_page = NULL; - seg->mr_offset = base; - seg->mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining); - remaining -= seg->mr_len; - base += seg->mr_len; + seg->mr_offset = vec->iov_base;
I thought the previous discussion was that this should be offset_in_page not the (virtual) iov_base. Tom.
+ seg->mr_len = vec->iov_len; ++seg; ++(*n); - page_offset = 0; } return seg; }
