From: "J. Bruce Fields" <bfields-uC3wQj2KruNg9hUCZPvPmw@public•gmane.org>
To: Tim Gardner <tim.gardner-Z7WLFzj8eWMS+FvcfC7Uqw@public•gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
Trond Myklebust
<Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public•gmane.org>,
"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>,
Tom Tucker <tom-/Yg/VP3ZvrM@public•gmane.org>,
Haggai Eran <haggaie-VPRAkNaXOzVWk0Htik3J/w@public•gmane.org>,
Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public•gmane.org>,
Shani Michaeli <shanim-VPRAkNaXOzVWk0Htik3J/w@public•gmane.org>,
linux-nfs-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org
Subject: Re: [PATCH linux-next v2] SUNRPC: rpcrdma_register_default_external: Dynamically allocate ib_phys_buf
Date: Mon, 11 Mar 2013 14:14:50 -0400 [thread overview]
Message-ID: <20130311181450.GC30618@fieldses.org> (raw)
In-Reply-To: <1363023447-22453-1-git-send-email-tim.gardner-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
On Mon, Mar 11, 2013 at 11:37:27AM -0600, Tim Gardner wrote:
> rpcrdma_register_default_external() is several frames into the call stack which
> goes deeper yet. You run the risk of stack corruption by declaring such a large
> automatic variable, so move the array of 'struct ib_phys_buf' objects into the
> requestor structure 'struct rpcrdma_req' (which is dynamically allocated) in
> order to silence the frame-larger-than warning.
>
> net/sunrpc/xprtrdma/verbs.c: In function 'rpcrdma_register_default_external':
> net/sunrpc/xprtrdma/verbs.c:1774:1: warning: the frame size of 1056 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>
> gcc version 4.6.3
>
> Cc: Trond Myklebust <Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public•gmane.org>
> Cc: "J. Bruce Fields" <bfields-uC3wQj2KruNg9hUCZPvPmw@public•gmane.org>
> Cc: "David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>
> Cc: Tom Tucker <tom-/Yg/VP3ZvrM@public•gmane.org>
> Cc: Haggai Eran <haggaie-VPRAkNaXOzVWk0Htik3J/w@public•gmane.org>
> Cc: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public•gmane.org>
> Cc: Shani Michaeli <shanim-VPRAkNaXOzVWk0Htik3J/w@public•gmane.org>
> Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public•gmane.org
> Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org
>
> Signed-off-by: Tim Gardner <tim.gardner-Z7WLFzj8eWMS+FvcfC7Uqw@public•gmane.org>
> ---
>
> v1 - Use kmalloc() to dynamically allocate and free the array of 'struct
> ib_phys_buf' objects
>
> v2 - Move the array of 'struct ib_phys_buf' objects into struct rpcrdma_req
> and pass this request down through rpcrdma_register_external() and
> rpcrdma_register_default_external(). This is less overhead then using
> kmalloc() and requires no extra error checking as the allocation burden is
> shifted to the transport client.
Oh good--so that works, and the req is the right place to put this? How
are you testing this?
(Just want to make it clear: I'm *not* an expert on the rdma code, so my
suggestion to put this in the rpcrdma_req was a suggestion for something
to look into, not a claim that it's correct.)
--b.
>
> net/sunrpc/xprtrdma/rpc_rdma.c | 2 +-
> net/sunrpc/xprtrdma/verbs.c | 11 ++++++-----
> net/sunrpc/xprtrdma/xprt_rdma.h | 3 ++-
> 3 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
> index e03725b..c89448b 100644
> --- a/net/sunrpc/xprtrdma/rpc_rdma.c
> +++ b/net/sunrpc/xprtrdma/rpc_rdma.c
> @@ -203,7 +203,7 @@ rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
>
> do {
> /* bind/register the memory, then build chunk from result. */
> - int n = rpcrdma_register_external(seg, nsegs,
> + int n = rpcrdma_register_external(req, seg, nsegs,
> cur_wchunk != NULL, r_xprt);
> if (n <= 0)
> goto out;
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 93726560..5b439ed 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -1730,13 +1730,14 @@ rpcrdma_deregister_memwin_external(struct rpcrdma_mr_seg *seg,
> }
>
> static int
> -rpcrdma_register_default_external(struct rpcrdma_mr_seg *seg,
> - int *nsegs, int writing, struct rpcrdma_ia *ia)
> +rpcrdma_register_default_external(struct rpcrdma_req *req,
> + struct rpcrdma_mr_seg *seg, int *nsegs, int writing,
> + struct rpcrdma_ia *ia)
> {
> int mem_priv = (writing ? IB_ACCESS_REMOTE_WRITE :
> IB_ACCESS_REMOTE_READ);
> struct rpcrdma_mr_seg *seg1 = seg;
> - struct ib_phys_buf ipb[RPCRDMA_MAX_DATA_SEGS];
> + struct ib_phys_buf *ipb = req->rl_ipb;
> int len, i, rc = 0;
>
> if (*nsegs > RPCRDMA_MAX_DATA_SEGS)
> @@ -1791,7 +1792,7 @@ rpcrdma_deregister_default_external(struct rpcrdma_mr_seg *seg,
> }
>
> int
> -rpcrdma_register_external(struct rpcrdma_mr_seg *seg,
> +rpcrdma_register_external(struct rpcrdma_req *req, struct rpcrdma_mr_seg *seg,
> int nsegs, int writing, struct rpcrdma_xprt *r_xprt)
> {
> struct rpcrdma_ia *ia = &r_xprt->rx_ia;
> @@ -1827,7 +1828,7 @@ rpcrdma_register_external(struct rpcrdma_mr_seg *seg,
>
> /* Default registration each time */
> default:
> - rc = rpcrdma_register_default_external(seg, &nsegs, writing, ia);
> + rc = rpcrdma_register_default_external(req, seg, &nsegs, writing, ia);
> break;
> }
> if (rc)
> diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
> index cc1445d..b10ed34 100644
> --- a/net/sunrpc/xprtrdma/xprt_rdma.h
> +++ b/net/sunrpc/xprtrdma/xprt_rdma.h
> @@ -192,6 +192,7 @@ struct rpcrdma_req {
> struct ib_sge rl_send_iov[4]; /* for active requests */
> struct ib_sge rl_iov; /* for posting */
> struct ib_mr *rl_handle; /* handle for mem in rl_iov */
> + struct ib_phys_buf rl_ipb[RPCRDMA_MAX_DATA_SEGS]; /* temp work array */
> char rl_base[MAX_RPCRDMAHDR]; /* start of actual buffer */
> __u32 rl_xdr_buf[0]; /* start of returned rpc rq_buffer */
> };
> @@ -327,7 +328,7 @@ int rpcrdma_register_internal(struct rpcrdma_ia *, void *, int,
> int rpcrdma_deregister_internal(struct rpcrdma_ia *,
> struct ib_mr *, struct ib_sge *);
>
> -int rpcrdma_register_external(struct rpcrdma_mr_seg *,
> +int rpcrdma_register_external(struct rpcrdma_req *, struct rpcrdma_mr_seg *,
> int, int, struct rpcrdma_xprt *);
> int rpcrdma_deregister_external(struct rpcrdma_mr_seg *,
> struct rpcrdma_xprt *, void *);
> --
> 1.7.9.5
>
> --
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next prev parent reply other threads:[~2013-03-11 18:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-10 15:39 [PATCH linux-next] SUNRPC: rpcrdma_register_default_external: Dynamically allocate ib_phys_buf Tim Gardner
[not found] ` <1362929953-63785-1-git-send-email-tim.gardner-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
2013-03-10 17:16 ` Tom Tucker
2013-03-10 18:20 ` Tim Gardner
2013-03-10 20:28 ` J. Bruce Fields
[not found] ` <20130310202838.GL31448-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2013-03-11 17:37 ` [PATCH linux-next v2] " Tim Gardner
[not found] ` <1363023447-22453-1-git-send-email-tim.gardner-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
2013-03-11 18:14 ` J. Bruce Fields [this message]
[not found] ` <20130311181450.GC30618-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2013-03-11 18:51 ` Tim Gardner
2013-03-11 19:15 ` J. Bruce Fields
[not found] ` <20130311191545.GA642-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2013-03-11 19:48 ` Myklebust, Trond
[not found] ` <4FA345DA4F4AE44899BD2B03EEEC2FA9286BA156-UCI0kNdgLrHLJmV3vhxcH3OR4cbS7gtM96Bgd4bDwmQ@public.gmane.org>
2013-03-11 20:00 ` J. Bruce Fields
2013-03-11 21:15 ` [PATCH linux-next v3] " Tim Gardner
[not found] ` <1363036508-24935-1-git-send-email-tim.gardner-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
2013-03-11 21:25 ` J. Bruce Fields
[not found] ` <20130311212535.GG642-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2013-03-11 23:02 ` Tom Tucker
2013-03-12 2:53 ` Tim Gardner
[not found] ` <513E989E.8060206-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
2013-03-12 3:40 ` Tom Tucker
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