Re: [PATCH v2] mac80211: LLVMLinux: Remove VLAIS usage from mac80211

[Joe Perches <joe-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org>]

On Fri, 2014-03-07 at 18:15 -0800, Behan Webster wrote:
> On 03/07/14 17:56, Joe Perches wrote:
> > On Fri, 2014-03-07 at 17:26 -0800, behanw-k/hB3zQhLwledRVtV/plodBPR1lH4CV8@public.gmane.org wrote:
> >> From: Jan-Simon Möller <dl9pf-Mmb7MZpHnFY@public.gmane.org>
> >>
> >> Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
> >> compliant equivalent. This is the original VLAIS struct.
> > []
> >> diff --git a/net/mac80211/aes_ccm.c b/net/mac80211/aes_ccm.c
> > []
> >> @@ -23,12 +23,14 @@ void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
> >>   			       u8 *data, size_t data_len, u8 *mic)
> >>   {
> >>   	struct scatterlist assoc, pt, ct[2];
> >> -	struct {
> >> -		struct aead_request	req;
> >> -		u8			priv[crypto_aead_reqsize(tfm)];
> >> -	} aead_req;
> >>   
> >> -	memset(&aead_req, 0, sizeof(aead_req));
> >> +	char aead_req_data[sizeof(struct aead_request) +
> >> +				crypto_aead_reqsize(tfm) +
> >> +				CRYPTO_MINALIGN] CRYPTO_MINALIGN_ATTR;
> > Can this be a too large amount of stack?
> >
> > Is crypto_aead_reqsize() limited to < ~1k?
> >
> > Perhaps it'd be better to use kzalloc for this
> > or another reserved pool
> No more stack being used than with the the original code. The stack 
> memory use is identical.

I do understand that, but that's not my question.

I appreciate you're getting this to compile for llvm.

Any idea of the max value of crypto_aead_reqsize?

include/linux/crypto.h:static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm)
include/linux/crypto.h-{
include/linux/crypto.h- return crypto_aead_crt(tfm)->reqsize;
include/linux/crypto.h-}

$ grep-2.5.4 -rP --include=*.[ch] "(?:->|\.)\s*\breqsize\s*=[^=][^;]+;" *
arch/x86/crypto/aesni-intel_glue.c:	tfm->crt_aead.reqsize = sizeof(struct aead_request)
		+ crypto_aead_reqsize(&cryptd_tfm->base);
crypto/chainiv.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
crypto/authenc.c:	tfm->crt_aead.reqsize = sizeof(struct authenc_request_ctx) +
				ctx->reqoff +
				max_t(unsigned int,
				crypto_ahash_reqsize(auth) +
				sizeof(struct ahash_request),
				sizeof(struct skcipher_givcrypt_request) +
				crypto_ablkcipher_reqsize(enc));
crypto/authencesn.c:	tfm->crt_aead.reqsize = sizeof(struct authenc_esn_request_ctx) +
				ctx->reqoff +
				max_t(unsigned int,
				crypto_ahash_reqsize(auth) +
				sizeof(struct ahash_request),
				sizeof(struct skcipher_givcrypt_request) +
				crypto_ablkcipher_reqsize(enc));
crypto/shash.c:	crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
crypto/cryptd.c:	tfm->crt_ablkcipher.reqsize =
		sizeof(struct cryptd_blkcipher_request_ctx);
crypto/cryptd.c:	tfm->crt_aead.reqsize = sizeof(struct cryptd_aead_request_ctx);
crypto/seqiv.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
crypto/seqiv.c:	tfm->crt_aead.reqsize = sizeof(struct aead_request);
crypto/ablk_helper.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request) +
		crypto_ablkcipher_reqsize(&cryptd_tfm->base);
crypto/ctr.c:	tfm->crt_ablkcipher.reqsize = align +
		sizeof(struct crypto_rfc3686_req_ctx) +
		crypto_ablkcipher_reqsize(cipher);
crypto/eseqiv.c:	tfm->crt_ablkcipher.reqsize = reqsize +
				      sizeof(struct ablkcipher_request);
crypto/ccm.c:	tfm->crt_aead.reqsize = align +
				sizeof(struct crypto_ccm_req_priv_ctx) +
				crypto_ablkcipher_reqsize(ctr);
crypto/ccm.c:	tfm->crt_aead.reqsize = sizeof(struct aead_request) +
				ALIGN(crypto_aead_reqsize(aead),
				      crypto_tfm_ctx_alignment()) +
				align + 16;
crypto/gcm.c:	tfm->crt_aead.reqsize = align +
		offsetof(struct crypto_gcm_req_priv_ctx, u) +
		max(sizeof(struct ablkcipher_request) +
		    crypto_ablkcipher_reqsize(ctr),
		    sizeof(struct ahash_request) +
		    crypto_ahash_reqsize(ghash));
crypto/gcm.c:	tfm->crt_aead.reqsize = sizeof(struct aead_request) +
				ALIGN(crypto_aead_reqsize(aead),
				      crypto_tfm_ctx_alignment()) +
				align + 16;
crypto/gcm.c:	tfm->crt_aead.reqsize = sizeof(struct crypto_rfc4543_req_ctx) +
				ALIGN(crypto_aead_reqsize(aead),
				      crypto_tfm_ctx_alignment()) +
				align + 16;
crypto/pcrypt.c:	tfm->crt_aead.reqsize = sizeof(struct pcrypt_request)
		+ sizeof(struct aead_givcrypt_request)
		+ crypto_aead_reqsize(cipher);
drivers/staging/sep/sep_crypto.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct this_task_ctx);
drivers/crypto/n2_core.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct n2_request_context);
drivers/crypto/mxs-dcp.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct dcp_aes_req_ctx);
drivers/crypto/sahara.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct sahara_aes_reqctx);
drivers/crypto/ccp/ccp-crypto-aes.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx);
drivers/crypto/ccp/ccp-crypto-aes.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx);
drivers/crypto/ccp/ccp-crypto-aes-xts.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx) +
				      fallback_tfm->base.crt_ablkcipher.reqsize;
drivers/crypto/s5p-sss.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct s5p_aes_reqctx);
drivers/crypto/atmel-aes.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct atmel_aes_reqctx);
drivers/crypto/ixp4xx_crypto.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct ablk_ctx);
drivers/crypto/ixp4xx_crypto.c:	tfm->crt_aead.reqsize = sizeof(struct aead_ctx);
drivers/crypto/omap-des.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct omap_des_reqctx);
drivers/crypto/mv_cesa.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct mv_req_ctx);
drivers/crypto/omap-aes.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct omap_aes_reqctx);
drivers/crypto/hifn_795x.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct hifn_request_context);
drivers/crypto/amcc/crypto4xx_core.c:		tfm->crt_ablkcipher.reqsize = sizeof(struct crypto4xx_ctx);
drivers/crypto/atmel-tdes.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct atmel_tdes_reqctx);
drivers/crypto/picoxcell_crypto.c:	tfm->crt_aead.reqsize = sizeof(struct spacc_req);
drivers/crypto/picoxcell_crypto.c:	tfm->crt_ablkcipher.reqsize = sizeof(struct spacc_req);
include/crypto/internal/hash.h:	tfm->reqsize = reqsize;


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