From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6846923C516 for ; Mon, 4 Aug 2025 22:48:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754347733; cv=none; b=Og+ANdkmxzQ0Jca3F2afptzjB2hcExJfRKSg/vYoZwORQXBSOEGjwWBuoaPt4rrkTsecuJzazV4QW/waV1aXhoJQ36gqRXyyBRNcaF5elbavmjubYFSupINUAeuuYefaXWc7vyU/DSSPD+43KJCmgXHxnRJqKo6JzK3L21vHY/4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754347733; c=relaxed/simple; bh=VVtpc65EtJGuIRuhMvWB72DRG08Rh9U5IMrXpqzL8aE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iPI/Bv2kl6/NnrC9T5wfz2iiIzOM1bBMRw9LJEQjxiSyccWBGGE7PuNkjobzGHAK6VwDee23WfCss34THmbg4+4uKFnrJaIhrTROzLSEChfiO2XbSubGSpdL48y7Q61ZPQuEMj79KD8LKepXFi+eI201uwUa91Uam+1TOMsYUbI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ao/NtOdI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ao/NtOdI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96F52C4CEF8; Mon, 4 Aug 2025 22:48:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754347732; bh=VVtpc65EtJGuIRuhMvWB72DRG08Rh9U5IMrXpqzL8aE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ao/NtOdIkf9CBlUjux+uSQVMawmXqIHiKHepbEmPoDGS+RXrPfu7U7JXxMO2nmBa4 t8BZMTLmwsOYIyUCTDdzFzggnqdUDk1QI+b3bVtK4xJB6+oIsgSa/OQ/LC6iQIbq2R v4XONJywmbviE9DUGUP48G5GeuKSROhTk95wBKbisIEOouB+VAghI8mP7HSPAnAosn 71Sl7AHFmgzvshsnXrXs855Js3/Yn8IPqChd8YYMXiI12ySdDIO9Za4eoxja/HkiiY wdJrfX5kRieZCsphpbmLJ8rSHFvVEVFCZPlshbwj2xT5tRvVxnC6EXKobKuVQ7Plf5 I3qW3a7ejVNFA== From: Eric Biggers To: Chuck Lever , Jeff Layton , linux-nfs@vger.kernel.org Cc: NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Eric Biggers Subject: [PATCH v2 2/2] nfsd: Eliminate an allocation in nfs4_make_rec_clidname() Date: Mon, 4 Aug 2025 22:47:00 +0000 Message-ID: <20250804224701.2278773-3-ebiggers@kernel.org> X-Mailer: git-send-email 2.50.1.565.gc32cd1483b-goog In-Reply-To: <20250804224701.2278773-1-ebiggers@kernel.org> References: <20250804224701.2278773-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Since MD5 digests are fixed-size, make nfs4_make_rec_clidname() store the digest in a stack buffer instead of a dynamically allocated buffer. Use MD5_DIGEST_SIZE instead of a hard-coded value, both in nfs4_make_rec_clidname() and in the definition of HEXDIR_LEN. Signed-off-by: Eric Biggers --- fs/nfsd/nfs4recover.c | 15 ++++----------- fs/nfsd/state.h | 4 +++- 2 files changed, 7 insertions(+), 12 deletions(-) diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 54f5e5392ef9..e2b9472e5c78 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -93,11 +93,11 @@ nfs4_reset_creds(const struct cred *original) } static int nfs4_make_rec_clidname(char dname[HEXDIR_LEN], const struct xdr_netobj *clname) { - struct xdr_netobj cksum; + u8 digest[MD5_DIGEST_SIZE]; struct crypto_shash *tfm; int status; dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n", clname->len, clname->data); @@ -105,27 +105,20 @@ nfs4_make_rec_clidname(char dname[HEXDIR_LEN], const struct xdr_netobj *clname) if (IS_ERR(tfm)) { status = PTR_ERR(tfm); goto out_no_tfm; } - cksum.len = crypto_shash_digestsize(tfm); - cksum.data = kmalloc(cksum.len, GFP_KERNEL); - if (cksum.data == NULL) { - status = -ENOMEM; - goto out; - } - status = crypto_shash_tfm_digest(tfm, clname->data, clname->len, - cksum.data); + digest); if (status) goto out; - sprintf(dname, "%*phN", 16, cksum.data); + static_assert(HEXDIR_LEN == 2 * MD5_DIGEST_SIZE + 1); + sprintf(dname, "%*phN", MD5_DIGEST_SIZE, digest); status = 0; out: - kfree(cksum.data); crypto_free_shash(tfm); out_no_tfm: return status; } diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index 8adc2550129e..b7d4c6d6f3d4 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -33,10 +33,11 @@ */ #ifndef _NFSD4_STATE_H #define _NFSD4_STATE_H +#include #include #include #include #include "nfsfh.h" #include "nfsd.h" @@ -379,11 +380,12 @@ struct nfsd4_sessionid { clientid_t clientid; u32 sequence; u32 reserved; }; -#define HEXDIR_LEN 33 /* hex version of 16 byte md5 of cl_name plus '\0' */ +/* Length of MD5 digest as hex, plus terminating '\0' */ +#define HEXDIR_LEN (2 * MD5_DIGEST_SIZE + 1) /* * State Meaning Where set * -------------------------------------------------------------------------- * | NFSD4_ACTIVE | Confirmed, active | Default | -- 2.50.1.565.gc32cd1483b-goog