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 34895219A9B for ; Thu, 15 May 2025 15:45:10 +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=1747323912; cv=none; b=pbyI3jhPJmhGAu+jh9tBqcLYQVkAq0TjS4DXNq6lW1TsNoQHHOqber3hAGlRNJ8N/zS+78eGWNlTxOIMqKFJ0eZaA4oSn5LElkZ8QaN0Gk9IJi8xxdAIP51wuROxtskK9Uz2pp1VCUU3w/5eiWxpNoi92TVCRI8k7b2jbP5Y+sc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747323912; c=relaxed/simple; bh=HqSYIbVWSorsHyz/DrltHpTuebYlN3giiUuAAwXS1So=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Hu/O7UYU0RUUqOG8OmWgCWCQgMk//ufjorXapwzUp8xU2yx4mjlDuj7Dk1GEZ7Y+DmB3OyZnn0rCXMmlghFYS6u1FvAAfPrI8FNrpIjG7ifwoWGTHv1/uunj7IYMBJ05VT8uP4Hygb7+jBhzdG/Maa7dYqs3dUOkcFYcPRLoZrQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VYoQMd18; 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="VYoQMd18" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00697C4CEE7; Thu, 15 May 2025 15:45:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747323910; bh=HqSYIbVWSorsHyz/DrltHpTuebYlN3giiUuAAwXS1So=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=VYoQMd18OGn3lOLOfAiWwvxyjbBOaT+hfwKjyxMLPPj7OtE4FUEsk57VfBvYPOfEV UWJfKnWwQ5sKDYVXEr9ssCIBtYVwy/gLpGLJ8kAwproyL5Vjd70+uO6ukLp/eFEhi7 AuAq26S08av7flD96VXl1T67jwzgE9BC4ZTSjZcw6GYGF8vwpZ2OCIB0ppuwzMQUPK cnFP9GETheMpQlYt6/f7969e3UkZSVsGb7BlTHjVr13Syx45yBxU6R0pGdf7KLJCLV A2anSCNiEnItPxxFy37O6d5McXcNg/szc+Qvo+V8BDlo1OhM24R/LVpRWOIFRUYztJ o1l3G/cwCehzQ== Message-ID: <27cdbdee24f514060ac62da98262f08fc19fd24e.camel@kernel.org> Subject: Re: [PATCH 2/3] sunrpc: simplify xdr_partial_copy_from_skb From: Jeff Layton To: Christoph Hellwig , Chuck Lever , Trond Myklebust , Anna Schumaker Cc: NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org Date: Thu, 15 May 2025 11:45:08 -0400 In-Reply-To: <20250515114906.32559-3-hch@lst.de> References: <20250515114906.32559-1-hch@lst.de> <20250515114906.32559-3-hch@lst.de> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Thu, 2025-05-15 at 13:48 +0200, Christoph Hellwig wrote: > csum_partial_copy_to_xdr can handle a checksumming and non-checksumming > case and implements this using a callback, which leads to a lot of > boilerplate code and indirect calls in the fast path. >=20 > Switch to storing a need_checksum flag in struct xdr_skb_reader instead > to remove the indirect call and simplify the code. >=20 > Signed-off-by: Christoph Hellwig > --- > net/sunrpc/socklib.c | 163 ++++++++++++++++--------------------------- > 1 file changed, 59 insertions(+), 104 deletions(-) >=20 > diff --git a/net/sunrpc/socklib.c b/net/sunrpc/socklib.c > index 1b2b84feeec6..75e31e3a3ced 100644 > --- a/net/sunrpc/socklib.c > +++ b/net/sunrpc/socklib.c > @@ -27,97 +27,60 @@ > struct xdr_skb_reader { > struct sk_buff *skb; > unsigned int offset; > + bool need_checksum; > size_t count; > __wsum csum; > }; > =20 > -typedef size_t (*xdr_skb_read_actor)(struct xdr_skb_reader *desc, void *= to, > - size_t len); > - > /** > * xdr_skb_read_bits - copy some data bits from skb to internal buffer > * @desc: sk_buff copy helper > * @to: copy destination > * @len: number of bytes to copy > * > - * Possibly called several times to iterate over an sk_buff and copy > - * data out of it. > + * Possibly called several times to iterate over an sk_buff and copy dat= a out of > + * it. > */ > static size_t > xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len) > { > - if (len > desc->count) > - len =3D desc->count; > - if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len))) > - return 0; > - desc->count -=3D len; > - desc->offset +=3D len; > - return len; > -} > + len =3D min(len, desc->count); > + > + if (desc->need_checksum) { > + __wsum csum; > + > + csum =3D skb_copy_and_csum_bits(desc->skb, desc->offset, to, len); > + desc->csum =3D csum_block_add(desc->csum, csum, desc->offset); > + } else { > + if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len))) > + return 0; > + } > =20 > -/** > - * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer > - * @desc: sk_buff copy helper > - * @to: copy destination > - * @len: number of bytes to copy > - * > - * Same as skb_read_bits, but calculate a checksum at the same time. > - */ > -static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, vo= id *to, size_t len) > -{ > - unsigned int pos; > - __wsum csum2; > - > - if (len > desc->count) > - len =3D desc->count; > - pos =3D desc->offset; > - csum2 =3D skb_copy_and_csum_bits(desc->skb, pos, to, len); > - desc->csum =3D csum_block_add(desc->csum, csum2, pos); > desc->count -=3D len; > desc->offset +=3D len; > return len; > } > =20 > -/** > - * xdr_partial_copy_from_skb - copy data out of an skb > - * @xdr: target XDR buffer > - * @base: starting offset > - * @desc: sk_buff copy helper > - * @copy_actor: virtual method for copying data > - * > - */ > static ssize_t > -xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct= xdr_skb_reader *desc, xdr_skb_read_actor copy_actor) > +xdr_partial_copy_from_skb(struct xdr_buf *xdr, struct xdr_skb_reader *de= sc) > { > - struct page **ppage =3D xdr->pages; > - unsigned int len, pglen =3D xdr->page_len; > - ssize_t copied =3D 0; > - size_t ret; > - > - len =3D xdr->head[0].iov_len; > - if (base < len) { > - len -=3D base; > - ret =3D copy_actor(desc, (char *)xdr->head[0].iov_base + base, len); > - copied +=3D ret; > - if (ret !=3D len || !desc->count) > - goto out; > - base =3D 0; > - } else > - base -=3D len; > - > - if (unlikely(pglen =3D=3D 0)) > - goto copy_tail; > - if (unlikely(base >=3D pglen)) { > - base -=3D pglen; > - goto copy_tail; > - } > - if (base || xdr->page_base) { > - pglen -=3D base; > - base +=3D xdr->page_base; > - ppage +=3D base >> PAGE_SHIFT; > - base &=3D ~PAGE_MASK; > - } > - do { > + struct page **ppage =3D xdr->pages + (xdr->page_base >> PAGE_SHIFT); > + unsigned int poff =3D xdr->page_base & ~PAGE_MASK; > + unsigned int pglen =3D xdr->page_len; > + ssize_t copied =3D 0; > + size_t ret; > + > + if (xdr->head[0].iov_len =3D=3D 0) > + return 0; > + > + ret =3D xdr_skb_read_bits(desc, xdr->head[0].iov_base, > + xdr->head[0].iov_len); > + if (ret !=3D xdr->head[0].iov_len || !desc->count) > + return ret; > + copied +=3D ret; > + > + while (pglen) { > + unsigned int len =3D min(PAGE_SIZE - poff, pglen); > char *kaddr; > =20 > /* ACL likes to be lazy in allocating pages - ACLs > @@ -126,36 +89,29 @@ xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsig= ned int base, struct xdr_skb > *ppage =3D alloc_page(GFP_NOWAIT | __GFP_NOWARN); > if (unlikely(*ppage =3D=3D NULL)) { > if (copied =3D=3D 0) > - copied =3D -ENOMEM; > - goto out; > + return -ENOMEM; > + return copied; > } > } > =20 > - len =3D PAGE_SIZE; > kaddr =3D kmap_atomic(*ppage); > - if (base) { > - len -=3D base; > - if (pglen < len) > - len =3D pglen; > - ret =3D copy_actor(desc, kaddr + base, len); > - base =3D 0; > - } else { > - if (pglen < len) > - len =3D pglen; > - ret =3D copy_actor(desc, kaddr, len); > - } > + ret =3D xdr_skb_read_bits(desc, kaddr + poff, len); > flush_dcache_page(*ppage); > kunmap_atomic(kaddr); > + > copied +=3D ret; > if (ret !=3D len || !desc->count) > - goto out; > + return copied; > ppage++; > - } while ((pglen -=3D len) !=3D 0); > -copy_tail: > - len =3D xdr->tail[0].iov_len; > - if (base < len) > - copied +=3D copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len= - base); > -out: > + pglen -=3D len; > + poff =3D 0; > + } > + > + if (xdr->tail[0].iov_len) { > + copied +=3D xdr_skb_read_bits(desc, xdr->tail[0].iov_base, > + xdr->tail[0].iov_len); > + } > + > return copied; > } > =20 > @@ -169,17 +125,22 @@ xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsi= gned int base, struct xdr_skb > */ > int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb) > { > - struct xdr_skb_reader desc; > - > - desc.skb =3D skb; > - desc.offset =3D 0; > - desc.count =3D skb->len - desc.offset; > + struct xdr_skb_reader desc =3D { > + .skb =3D skb, > + .count =3D skb->len - desc.offset, > + }; > =20 > - if (skb_csum_unnecessary(skb)) > - goto no_checksum; > + if (skb_csum_unnecessary(skb)) { > + if (xdr_partial_copy_from_skb(xdr, &desc) < 0) > + return -1; > + if (desc.count) > + return -1; > + return 0; > + } > =20 > + desc.need_checksum =3D true; > desc.csum =3D csum_partial(skb->data, desc.offset, skb->csum); > - if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits= ) < 0) > + if (xdr_partial_copy_from_skb(xdr, &desc) < 0) > return -1; > if (desc.offset !=3D skb->len) { > __wsum csum2; > @@ -194,12 +155,6 @@ int csum_partial_copy_to_xdr(struct xdr_buf *xdr, st= ruct sk_buff *skb) > !skb->csum_complete_sw) > netdev_rx_csum_fault(skb->dev, skb); > return 0; > -no_checksum: > - if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0) > - return -1; > - if (desc.count) > - return -1; > - return 0; > } > EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr); > =20 Reviewed-by: Jeff Layton