| Message ID | 20230130092157.1759539-21-hch@lst.de (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [01/23] block: factor out a bvec_set_page helper | expand |
Christoph Hellwig <hch@lst.de> wrote:
> + bvec_set_page(&bv, ZERO_PAGE(0), len, 0);
Maybe bvec_set_zero_page()?
David
On Mon, Jan 30, 2023 at 10:31:23AM +0000, David Howells wrote: > Christoph Hellwig <hch@lst.de> wrote: > > > + bvec_set_page(&bv, ZERO_PAGE(0), len, 0); > > Maybe bvec_set_zero_page()? Why?
Christoph Hellwig <hch@lst.de> wrote: > On Mon, Jan 30, 2023 at 10:31:23AM +0000, David Howells wrote: > > Christoph Hellwig <hch@lst.de> wrote: > > > > > + bvec_set_page(&bv, ZERO_PAGE(0), len, 0); > > > > Maybe bvec_set_zero_page()? > > Why? Seems to be something people want to do quite a lot and don't know about. I've seen places where someone allocates a buffer and clears it just to use as a source of zeros. There's at least one place in cifs, for example. I know about it from wrangling arch code, but most people working on Linux haven't done that. David
On Mon, Jan 30, 2023 at 11:24:15AM +0000, David Howells wrote: > Seems to be something people want to do quite a lot and don't know about. Hmm. Right now there is one case where it would be used, and there's about three that are and should be using bio_add_page. > I've seen places where someone allocates a buffer and clears it just to use as > a source of zeros. There's at least one place in cifs, for example. I know > about it from wrangling arch code, but most people working on Linux haven't > done that. But we don't really need a helper for every possible page use for that. People just need to learn about ZERO_PAGE.
Christoph Hellwig <hch@lst.de> wrote: > Use the bvec_set_page helper to initialize a bvec. > > Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: David Howells <dhowells@redhat.com>
diff --git a/net/rxrpc/rxperf.c b/net/rxrpc/rxperf.c index 16dcabb71ebe16..4a2e90015ca72c 100644 --- a/net/rxrpc/rxperf.c +++ b/net/rxrpc/rxperf.c @@ -493,7 +493,7 @@ static int rxperf_deliver_request(struct rxperf_call *call) static int rxperf_process_call(struct rxperf_call *call) { struct msghdr msg = {}; - struct bio_vec bv[1]; + struct bio_vec bv; struct kvec iov[1]; ssize_t n; size_t reply_len = call->reply_len, len; @@ -503,10 +503,8 @@ static int rxperf_process_call(struct rxperf_call *call) while (reply_len > 0) { len = min_t(size_t, reply_len, PAGE_SIZE); - bv[0].bv_page = ZERO_PAGE(0); - bv[0].bv_offset = 0; - bv[0].bv_len = len; - iov_iter_bvec(&msg.msg_iter, WRITE, bv, 1, len); + bvec_set_page(&bv, ZERO_PAGE(0), len, 0); + iov_iter_bvec(&msg.msg_iter, WRITE, &bv, 1, len); msg.msg_flags = MSG_MORE; n = rxrpc_kernel_send_data(rxperf_socket, call->rxcall, &msg, len, rxperf_notify_end_reply_tx);
Use the bvec_set_page helper to initialize a bvec. Signed-off-by: Christoph Hellwig <hch@lst.de> --- net/rxrpc/rxperf.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)