From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benny Halevy Subject: Re: [PATCH] nfs41: get rid of unused struct nfs41_exchange_id_res members Date: Tue, 05 May 2009 23:35:21 +0300 Message-ID: <4A00A309.8000305@panasas.com> References: <89c397150905010756h503498d4n9fd2f8bb3ce403c3@mail.gmail.com> <1241208886-5748-1-git-send-email-bhalevy@panasas.com> <1241552053.5174.44.camel@heimdal.trondhjem.org> <1241552374.5174.48.camel@heimdal.trondhjem.org> <1241552508.5174.50.camel@heimdal.trondhjem.org> <4A00A187.4040801@panasas.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from gw-ca.panasas.com ([209.116.51.66]:18806 "EHLO laguna.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753403AbZEEUfn (ORCPT ); Tue, 5 May 2009 16:35:43 -0400 In-Reply-To: <4A00A187.4040801@panasas.com> Sender: linux-next-owner@vger.kernel.org List-ID: To: Trond Myklebust Cc: Andy Adamson , pnfs@linux-nfs.org, Stephen Rothwell , linux-next@vger.kernel.org On 2009-05-05 23:28, Benny Halevy wrote: > On May. 05, 2009, 22:41 +0300, Trond Myklebust wrote: >> On Tue, 2009-05-05 at 15:39 -0400, Trond Myklebust wrote: >>> On Tue, 2009-05-05 at 15:34 -0400, Trond Myklebust wrote: >>>> On Fri, 2009-05-01 at 23:14 +0300, Benny Halevy wrote: >>>>> struct nfs41_exchange_id_res is currently allocated on the stack >>>>> insanely taking over 2K of stack space due to the NFS4_OPAQUE_LIMIT (1K( >>>>> byte arrays embedded in server_owner and server_scope. >>>>> Since these are not in use yet, this patch gets rid of them for the >>>>> time being. >>>>> >>>>> Signed-off-by: Benny Halevy >>>>> --- >>>>> fs/nfs/nfs4xdr.c | 27 ++++++++++++++------------- >>>>> include/linux/nfs_xdr.h | 3 --- >>>>> 2 files changed, 14 insertions(+), 16 deletions(-) >>>>> >>>>> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c >>>>> index 80af0ae..3350d19 100644 >>>>> --- a/fs/nfs/nfs4xdr.c >>>>> +++ b/fs/nfs/nfs4xdr.c >>>>> @@ -4185,8 +4185,8 @@ static int decode_delegreturn(struct xdr_stream *xdr) >>>>> static int decode_exchange_id(struct xdr_stream *xdr, >>>>> struct nfs41_exchange_id_res *res) >>>>> { >>>>> - uint32_t *p; >>>>> - int status, dummy; >>>>> + uint32_t *p, dummy; >> Oh, and 'p' _always_ has to be of type '__be32', otherwise the 'sparse' >> checker will yell at you. > > Thanks! I'll send a fixed version > of this patch and also look into the rest of the xdr code. > >>>>> + int status; >>>>> struct nfs_client *clp = res->client; >>>>> >>>>> status = decode_op_hdr(xdr, OP_EXCHANGE_ID); >>>>> @@ -4204,25 +4204,26 @@ static int decode_exchange_id(struct xdr_stream *xdr, >>>>> if (dummy != SP4_NONE) >>>>> return -EIO; >>>>> >>>>> - /* minor_id */ >>>>> + /* Throw away minor_id */ >>>>> READ_BUF(8); >>>>> - READ64(res->server_owner.minor_id); >>>>> + p += 8; >>>> ^^^^^^^^ Err... This isn't the same thing at all! > > Ouch, of course. What did I smoke that day? > >>>> You're suddenly skipping 10=words instead of the original 2. READ_BUF() >>>> will already take care of updating the 'p' pointer. > > Which p? > It takes care of argp->p, not the local 'p' variable, doesn't it. Grr, I meant "xdr->p" of course, via xdr_inline_decode (argp is the server's READ_BUF, sigh) > p += 2 has an equivalent side effect on 'p' as doing READ64. > I can do "p = argp;" instead though to reset 'p' onto p = xdr->p; ... Benny > the current xdr stream "head". > >>> BTW, this is exactly why the whole READ_BUF(), READ*(), WRITE*() macro >>> crap is so utterly broken. The magic that happens to the 'p' pointer is >>> completely opaque to someone unfamiliar with the code. > > I completely agree. We're dealing with bits and bytes (or 32 bit words > actually) at the wrong abstraction layer. > >>>>> >>>>> - /* Major id */ >>>>> + /* Throw away Major id */ >>>>> READ_BUF(4); >>>>> - READ32(res->server_owner.major_id_sz); >>>>> - READ_BUF(res->server_owner.major_id_sz); >>>>> - COPYMEM(res->server_owner.major_id, res->server_owner.major_id_sz); >>>>> + READ32(dummy); >>>>> + READ_BUF(dummy); >>>>> + p += XDR_QUADLEN(dummy); >>>> ^^^^^^^^^^^^^^^^^^^^^^^^^ Ditto. You're skipping 2*dummy words. > > Why? > READ_BUF increments argp->p in XDR_QUADLEN(dummy) words > and the local p should be adjusted correspondingly. > This used to happen as the side effect of COPY_MEM. > >>>>> >>>>> - /* server_scope */ >>>>> + /* Throw away server_scope */ >>>>> READ_BUF(4); >>>>> - READ32(res->server_scope.server_scope_sz); >>>>> - READ_BUF(res->server_scope.server_scope_sz); >>>>> - COPYMEM(res->server_scope.server_scope, >>>>> - res->server_scope.server_scope_sz); >>>>> + READ32(dummy); >>>>> + READ_BUF(dummy); >>>>> + p += XDR_QUADLEN(dummy); >>>> ^^^^^^^^^^^^^^^^^^^^^^^^ Ditto > > Ditto > >>>>> + >>>>> /* Throw away Implementation id array */ >>>>> READ_BUF(4); >>>>> READ32(dummy); >>>>> + READ_BUF(dummy); >>>>> p += XDR_QUADLEN(dummy); >>>> ^^^^^^^^^^^^^^^^^^^^^^^^ Ditto >>>> > > and here too... > > BTW, Calling READ_BUF here was missing before, so this could be put > in a patch of its own, and adjusting p is not really necessary since > we're about to exit the function... > > In any case, are we going to squash these fixes into the respective > queued patch, or would like to start accumulating the patches for > 2.6.31 without rebasing? > > Benny > >>>>> >>>>> return 0; >>>>> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h >>>>> index 071a6d1..62f63fb 100644 >>>>> --- a/include/linux/nfs_xdr.h >>>>> +++ b/include/linux/nfs_xdr.h >>>>> @@ -925,9 +925,6 @@ struct server_scope { >>>>> struct nfs41_exchange_id_res { >>>>> struct nfs_client *client; >>>>> u32 flags; >>>>> - struct server_owner server_owner; >>>>> - struct server_scope server_scope; >>>>> - struct nfs_impl_id4 impl_id; >>>>> }; >>>>> >>>>> struct nfs41_create_session_args { >>