On Wed, Oct 15, 2008 at 05:00:24PM -0400, andros@xxxxxxxxxx wrote:
> From: Andy Adamson <andros@xxxxxxxxxx>
>
> For EOS, NFSD compound RPC deferred processing should restart operation which
> caused the deferral.
>
> Add a callback and a defer_data pointer in svc_rqst to enable svc_defer to
> save partial result state in the deferral request.
>
> Add page pointer storage to svc_deferred_req to cache the pages holding the
> partially processed request.
>
> Add callbacks and a defer_data pointer in svc_deferred_request to enable
> svc_deferred_recv to restore and release the partial result state.
>
> Signed-off-by: Andy Adamson<andros@xxxxxxxxx>
Could you fix the missing space there?
> ---
> include/linux/sunrpc/svc.h | 10 ++++++++++
> net/sunrpc/svc_xprt.c | 20 +++++++++++++++-----
> 2 files changed, 25 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
> index dc69068..46a4097 100644
> --- a/include/linux/sunrpc/svc.h
> +++ b/include/linux/sunrpc/svc.h
> @@ -215,6 +215,9 @@ struct svc_rqst {
> struct svc_cred rq_cred; /* auth info */
> void * rq_xprt_ctxt; /* transport specific context ptr */
> struct svc_deferred_req*rq_deferred; /* deferred request we are replaying */
> + /* callback to save deferred request state */
> + void (*rq_save_state)(struct svc_rqst *, struct svc_deferred_req *);
> + void *rq_defer_data; /* defer state data to save */
>
> size_t rq_xprt_hlen; /* xprt header len */
> struct xdr_buf rq_arg;
> @@ -323,6 +326,13 @@ struct svc_deferred_req {
> union svc_addr_u daddr; /* where reply must come from */
> struct cache_deferred_req handle;
> size_t xprt_hlen;
> + /* callbacks to restore and release deferred request state
> + * set in rq_save_state */
> + void (*restore_state)(struct svc_rqst *, struct svc_deferred_req *);
> + void (*release_state)(struct svc_deferred_req *);
> + void *defer_data; /* defer state data */
> + struct page *respages[RPCSVC_MAXPAGES];
> + short resused;
> int argslen;
> __be32 args[0];
> };
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index e46c825..531b325 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -876,6 +876,8 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
> struct svc_xprt *xprt = dr->xprt;
>
> if (too_many) {
> + if (dr->release_state)
> + dr->release_state(dr);
> svc_xprt_put(xprt);
> kfree(dr);
> return;
> @@ -902,10 +904,10 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
> static struct cache_deferred_req *svc_defer(struct cache_req *req)
> {
> struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
> - struct svc_deferred_req *dr;
> + struct svc_deferred_req *dr = NULL;
>
> if (rqstp->rq_arg.page_len)
> - return NULL; /* if more than a page, give up FIXME */
> + goto out; /* if more than a page, give up FIXME */
> if (rqstp->rq_deferred) {
> dr = rqstp->rq_deferred;
> rqstp->rq_deferred = NULL;
> @@ -914,9 +916,9 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req)
> size_t size;
> /* FIXME maybe discard if size too large */
> size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
> - dr = kmalloc(size, GFP_KERNEL);
> + dr = kzalloc(size, GFP_KERNEL);
> if (dr == NULL)
> - return NULL;
> + goto out;
>
> dr->handle.owner = rqstp->rq_server;
> dr->prot = rqstp->rq_prot;
> @@ -935,7 +937,13 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req)
> dr->xprt = rqstp->rq_xprt;
>
> dr->handle.revisit = svc_revisit;
> - return &dr->handle;
> + if (rqstp->rq_save_state)
> + rqstp->rq_save_state(rqstp, dr);
> +out:
> + rqstp->rq_defer_data = NULL;
> + rqstp->rq_save_state = NULL;
> +
> + return dr ? &dr->handle: NULL;
I may not be thinking this through clearly, but: I think the correct
place to initialize rq_defer_data and rq_save_state is not here but at
the very start of request processing (in svc_recv or at the top of
svc_process). We shouldn't depend on svc_defer()--it may never get
called.
--b.
> }
>
> /*
> @@ -959,6 +967,8 @@ static int svc_deferred_recv(struct svc_rqst *rqstp)
> rqstp->rq_xprt_hlen = dr->xprt_hlen;
> rqstp->rq_daddr = dr->daddr;
> rqstp->rq_respages = rqstp->rq_pages;
> + if (dr->restore_state)
> + dr->restore_state(rqstp, dr);
> return (dr->argslen<<2) - dr->xprt_hlen;
> }
>
> --
> 1.5.4.3
>
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