Hi Trond,
On Thu, Jan 3, 2019 at 7:14 AM Trond Myklebust <trondmy@xxxxxxxxx> wrote:
> After receiving data into the page cache, we need to call flush_dcache_page()
> for the architectures that define it.
>
> Fixes: 277e4ab7d530b ("SUNRPC: Simplify TCP receive code by switching...")
> Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # v4.20
Thanks for your patch!
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -48,6 +48,7 @@
> #include <net/udp.h>
> #include <net/tcp.h>
> #include <linux/bvec.h>
> +#include <linux/highmem.h>
> #include <linux/uio.h>
>
> #include <trace/events/sunrpc.h>
> @@ -380,6 +381,27 @@ xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
> return sock_recvmsg(sock, msg, flags);
> }
>
> +#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
> +static void
> +xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
> +{
> + struct bvec_iter bi, __start = {
As for_each_bvec() assigns __start to bi, and you don't need __start
afterwards, both variables can be merged into a single one.
But perhaps that would make too many assumptions about the
implementation of for_each_bvec()?
> + .bi_size = count,
> + };
> + struct bio_vec bv;
> +
> + bvec_iter_advance(bvec, &__start, seek & PAGE_MASK);
> +
> + for_each_bvec(bv, bvec, bi, __start)
> + flush_dcache_page(bv.bv_page);
> +}
> +#else
> +static inline void
> +xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
> +{
> +}
> +#endif
> +
> static ssize_t
> xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
> struct xdr_buf *buf, size_t count, size_t seek, size_t *read)
> @@ -413,6 +435,7 @@ xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
> seek + buf->page_base);
> if (ret <= 0)
> goto sock_err;
> + xs_flush_bvec(buf->bvec, ret, seek + buf->page_base);
> offset += ret - buf->page_base;
> if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
> goto out;
I don't understand the code well enough to see why the call to
xs_flush_bvec() is needed in this branch only, but it does fix TCP
NFS on RBTX4927, so
Tested-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
