What's not to like about a log that uses the words "with aplomb"? :)
Minor related comment/question below.
On 2/2/2021 9:42 AM, Chuck Lever wrote:
Clean up.
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.
A related simplification removes an extra conditional branch from
the SGL set-up loop in frwr_map(): Instead of using either
sg_set_page() or sg_set_buf(), initialize the mr_page field properly
when rpcrdma_convert_kvec() converts the kvec to an SGL entry.
frwr_map() can then invoke sg_set_page() unconditionally.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/frwr_ops.c | 10 ++--------
net/sunrpc/xprtrdma/rpc_rdma.c | 21 +++++----------------
net/sunrpc/xprtrdma/xprt_rdma.h | 2 +-
3 files changed, 8 insertions(+), 25 deletions(-)
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index baca49fe83af..5eb044a5f0be 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -306,14 +306,8 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
if (nsegs > ep->re_max_fr_depth)
nsegs = ep->re_max_fr_depth;
for (i = 0; i < nsegs;) {
- if (seg->mr_page)
- sg_set_page(&mr->mr_sg[i],
- seg->mr_page,
- seg->mr_len,
- offset_in_page(seg->mr_offset));
- else
- sg_set_buf(&mr->mr_sg[i], seg->mr_offset,
- seg->mr_len);
+ sg_set_page(&mr->mr_sg[i], seg->mr_page,
+ seg->mr_len, offset_in_page(seg->mr_offset));
++seg;
++i;
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 8f5d0cb68360..529adb6ad4db 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) {
- 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;
+ if (vec->iov_len) {
+ seg->mr_page = virt_to_page(vec->iov_base);
+ seg->mr_offset = vec->iov_base;
+ seg->mr_len = vec->iov_len;
++seg;
++(*n);
- page_offset = 0;
}
return seg;
}
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 94b28657aeeb..4a9fe6592795 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -285,7 +285,7 @@ enum {
struct rpcrdma_mr_seg { /* chunk descriptors */
u32 mr_len; /* length of chunk or segment */
- struct page *mr_page; /* owning page, if any */
+ struct page *mr_page; /* underlying struct page */
char *mr_offset; /* kva if no page, else offset */
Is this comment ("kva if no page") actually correct? The hunk just
above is an example of a case where mr_page is set, yet mr_offset
is an iov_base. Is iov_base not a kva?
Tom.
};
