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Re: [PATCH v8 3/7] 9pfs: split out fs driver core of v9fs_co_readdir()
From: |
Greg Kurz |
Subject: |
Re: [PATCH v8 3/7] 9pfs: split out fs driver core of v9fs_co_readdir() |
Date: |
Wed, 29 Jul 2020 18:02:56 +0200 |
On Wed, 29 Jul 2020 10:11:54 +0200
Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:
> The implementation of v9fs_co_readdir() has two parts: the outer
> part is executed by main I/O thread, whereas the inner part is
> executed by fs driver on a background I/O thread.
>
> Move the inner part to its own new, private function do_readdir(),
> so it can be shared by another upcoming new function.
>
> This is just a preparatory patch for the subsequent patch, with the
> purpose to avoid the next patch to clutter the overall diff.
>
> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> ---
> hw/9pfs/codir.c | 37 +++++++++++++++++++++++--------------
> 1 file changed, 23 insertions(+), 14 deletions(-)
>
> diff --git a/hw/9pfs/codir.c b/hw/9pfs/codir.c
> index 73f9a751e1..ff57fb8619 100644
> --- a/hw/9pfs/codir.c
> +++ b/hw/9pfs/codir.c
> @@ -18,28 +18,37 @@
> #include "qemu/main-loop.h"
> #include "coth.h"
>
> +/*
> + * This must solely be executed on a background IO thread.
> + */
Well, technically this function could be called from any context
but of course calling it from the main I/O thread when handling
T_readdir would make the request synchronous, which is certainly
not what we want. So I'm not sure this comment brings much.
Anyway, the code change is okay so:
Reviewed-by: Greg Kurz <groug@kaod.org>
> +static int do_readdir(V9fsPDU *pdu, V9fsFidState *fidp, struct dirent **dent)
> +{
> + int err = 0;
> + V9fsState *s = pdu->s;
> + struct dirent *entry;
> +
> + errno = 0;
> + entry = s->ops->readdir(&s->ctx, &fidp->fs);
> + if (!entry && errno) {
> + *dent = NULL;
> + err = -errno;
> + } else {
> + *dent = entry;
> + }
> + return err;
> +}
> +
> int coroutine_fn v9fs_co_readdir(V9fsPDU *pdu, V9fsFidState *fidp,
> struct dirent **dent)
> {
> int err;
> - V9fsState *s = pdu->s;
>
> if (v9fs_request_cancelled(pdu)) {
> return -EINTR;
> }
> - v9fs_co_run_in_worker(
> - {
> - struct dirent *entry;
> -
> - errno = 0;
> - entry = s->ops->readdir(&s->ctx, &fidp->fs);
> - if (!entry && errno) {
> - err = -errno;
> - } else {
> - *dent = entry;
> - err = 0;
> - }
> - });
> + v9fs_co_run_in_worker({
> + err = do_readdir(pdu, fidp, dent);
> + });
> return err;
> }
>
- [PATCH v8 0/7] 9pfs: readdir optimization, Christian Schoenebeck, 2020/07/29
- [PATCH v8 2/7] 9pfs: make v9fs_readdir_response_size() public, Christian Schoenebeck, 2020/07/29
- [PATCH v8 5/7] 9pfs: T_readdir latency optimization, Christian Schoenebeck, 2020/07/29
- [PATCH v8 6/7] 9pfs: differentiate readdir lock between 9P2000.u vs. 9P2000.L, Christian Schoenebeck, 2020/07/29
- [PATCH v8 1/7] tests/virtio-9p: added split readdir tests, Christian Schoenebeck, 2020/07/29
- [PATCH v8 4/7] 9pfs: add new function v9fs_co_readdir_many(), Christian Schoenebeck, 2020/07/29
- [PATCH v8 3/7] 9pfs: split out fs driver core of v9fs_co_readdir(), Christian Schoenebeck, 2020/07/29
- Re: [PATCH v8 3/7] 9pfs: split out fs driver core of v9fs_co_readdir(),
Greg Kurz <=
- [PATCH v8 7/7] 9pfs: clarify latency of v9fs_co_run_in_worker(), Christian Schoenebeck, 2020/07/29