| Message ID | 1488830488-18506-2-git-send-email-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> +struct xen_9pfs_header { > + uint32_t size; > + uint8_t id; > + uint16_t tag; I realize that this is in the spec now and it's probably too late to ask this question but wouldn't it be better if id and tag were swapped? No need to pack and potentially faster access to tag. -boris > +} __attribute__((packed)); > + > +#define XEN_9PFS_RING_ORDER 6 > +#define XEN_9PFS_RING_SIZE XEN_FLEX_RING_SIZE(XEN_9PFS_RING_ORDER) > +DEFINE_XEN_FLEX_RING_AND_INTF(xen_9pfs); > + > +#endif
On Mon, 6 Mar 2017, Boris Ostrovsky wrote: > > + uint32_t size; > > + uint8_t id; > > + uint16_t tag; > > I realize that this is in the spec now and it's probably too late to ask > this question but wouldn't it be better if id and tag were swapped? No > need to pack and potentially faster access to tag. I cannot do anything about it: that struct is defined by the 9pfs specification (not the Xen spec, the general 9pfs spec). See: https://www.usenix.org/legacy/event/usenix05/tech/freenix/full_papers/hensbergen/hensbergen.pdf > > +} __attribute__((packed)); > > + > > +#define XEN_9PFS_RING_ORDER 6 > > +#define XEN_9PFS_RING_SIZE XEN_FLEX_RING_SIZE(XEN_9PFS_RING_ORDER) > > +DEFINE_XEN_FLEX_RING_AND_INTF(xen_9pfs); > > + > > +#endif >
On 03/06/2017 04:36 PM, Stefano Stabellini wrote: > On Mon, 6 Mar 2017, Boris Ostrovsky wrote: >>> + uint32_t size; >>> + uint8_t id; >>> + uint16_t tag; >> I realize that this is in the spec now and it's probably too late to ask >> this question but wouldn't it be better if id and tag were swapped? No >> need to pack and potentially faster access to tag. > I cannot do anything about it: that struct is defined by the 9pfs > specification (not the Xen spec, the general 9pfs spec). See: Oh, I thought it was Xen-specific (because it's described in 9pfs.markdown). Nevermind then. -boris > > https://www.usenix.org/legacy/event/usenix05/tech/freenix/full_papers/hensbergen/hensbergen.pdf > >>> +} __attribute__((packed)); >>> + >>> +#define XEN_9PFS_RING_ORDER 6 >>> +#define XEN_9PFS_RING_SIZE XEN_FLEX_RING_SIZE(XEN_9PFS_RING_ORDER) >>> +DEFINE_XEN_FLEX_RING_AND_INTF(xen_9pfs); >>> + >>> +#endif
diff --git a/include/xen/interface/io/9pfs.h b/include/xen/interface/io/9pfs.h new file mode 100644 index 0000000..276eda4 --- /dev/null +++ b/include/xen/interface/io/9pfs.h @@ -0,0 +1,40 @@ +/* + * 9pfs.h -- Xen 9PFS transport + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to + * deal in the Software without restriction, including without limitation the + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + * + * Copyright (C) 2017 Stefano Stabellini <stefano@aporeto.com> + */ + +#ifndef __XEN_PUBLIC_IO_9PFS_H__ +#define __XEN_PUBLIC_IO_9PFS_H__ + +#include "xen/interface/io/ring.h" + +struct xen_9pfs_header { + uint32_t size; + uint8_t id; + uint16_t tag; +} __attribute__((packed)); + +#define XEN_9PFS_RING_ORDER 6 +#define XEN_9PFS_RING_SIZE XEN_FLEX_RING_SIZE(XEN_9PFS_RING_ORDER) +DEFINE_XEN_FLEX_RING_AND_INTF(xen_9pfs); + +#endif
It uses the new ring.h macros to declare rings and interfaces. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> CC: konrad.wilk@oracle.com CC: boris.ostrovsky@oracle.com CC: jgross@suse.com --- include/xen/interface/io/9pfs.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 include/xen/interface/io/9pfs.h