From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=MPiIN9k3; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTPS id 83E525A0262 for ; Thu, 12 Mar 2026 09:20:21 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773303620; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=l1XSxzY8qhJgsVfiK89j0cNv2UQVgMUBTHeurEMMoh8=; b=MPiIN9k3Bpq5P0zgFd5J2QjaOABqgupWwR23Ca6h+pXaZ4/WP8q262Qkswedp3Kg5AbSey xU/wBD8hK9fXf6TgB/RYa1skYaKbg3rYPnJRdeBDfC7TLaNa5huflkZ+F8ExUvEv/ACube WGGzwUgD+ojPaqtBC279txHeGUV9P+Y= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-664-W9iI1wrAOVu4B5zCaSMdzA-1; Thu, 12 Mar 2026 04:20:19 -0400 X-MC-Unique: W9iI1wrAOVu4B5zCaSMdzA-1 X-Mimecast-MFC-AGG-ID: W9iI1wrAOVu4B5zCaSMdzA_1773303618 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-439ca4b3d0bso491170f8f.3 for ; Thu, 12 Mar 2026 01:20:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773303617; x=1773908417; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=l1XSxzY8qhJgsVfiK89j0cNv2UQVgMUBTHeurEMMoh8=; b=dViEHH6Bvm/bFHNGAn9t9d3SEPn+BBvCxjiWmzpDE70JKtZs02M4fIptXR/jSWDcHp 89yKOEUhyNPFxnabJcO2AQqrOLKWL7Ykqjsa2pgkAIxha2qhkTXOYz20IEqCAQecfFss 7KCoZ/+z8A6dslnR7v1X4sXE1+mABsKIBtWLih0/JbQ4bJvXhZXzFBJWOBDDdMszuUKc qCFoGKzzCIx06uZYSoN+VTdMK1FzY+sfdUzXFoyMIlpjbgYAhgidkiugu4ZWDpuPTD3E 9git2UZ0mHs18ihuPobKD5TYM4DEX4nyuT/3es4F0ISlLSxBYNplwqm0+DhuxJLTyAUi XfcA== X-Gm-Message-State: AOJu0YymdmdiUguvFPE0K3IiJFivGfXaiX/PFCtbpS0K4NsEbGcE4S4Y alKWdGP1yUpdS6mwhke3kMZiUXyB2ixnoxDS5N/i3d7PohhGxpKV+fUbZ9/p8MpNd9IAsyOLr+I VdX2G7FGMjUgH7kZpCu+DPIFmnAyrY92GzpUYtHbik7TmMjJkLiL4Npo9WLASIg== X-Gm-Gg: ATEYQzwmbGWJj+rTOGvyqOD2gTYhPsfwhVg7VpJdb0G96ChEL2G+5PT5MWXUyGGe+If /bba8FAMpbFw5ZIeiZYLpw3YOFrfDcyLKAOwZFujnwkX1ehLys0hKpy8sK6A9o/IJXCvDMJvY9F 9/A2ntpVPjRIzShOreTITQEamsv8KAoeLHCWebrgqvOeOmRc9y2v2vkC5bUaRtHi5qgEPMT5Fho 74ldTfoLomaWBXbydpLwZs9cgeg9ypd9+dyLh+NmcxzPC+sNcxc1O/IpaybF+FI08Ag8+3/VxXF LfN2fpMcrVzS762AnZwXMCrTytQyGa/jusmMFic50UUDjy9A3OOv4HLG9bDw7h5Su657bh1Mtka Tv0LZFa2kOM/L4aJ07LSarnZmeXAy1SnBILAcmZQzwDbGDvIW3DnSTM2WzLJDyDCAEg== X-Received: by 2002:a5d:5604:0:b0:439:fe98:20f9 with SMTP id ffacd0b85a97d-439fe982138mr2483354f8f.27.1773303617538; Thu, 12 Mar 2026 01:20:17 -0700 (PDT) X-Received: by 2002:a5d:5604:0:b0:439:fe98:20f9 with SMTP id ffacd0b85a97d-439fe982138mr2483330f8f.27.1773303617006; Thu, 12 Mar 2026 01:20:17 -0700 (PDT) Received: from ?IPV6:2a01:e0a:e10:ef90:4326:a36e:a7cb:624b? ([2a01:e0a:e10:ef90:4326:a36e:a7cb:624b]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-439fe1a737csm5606977f8f.10.2026.03.12.01.20.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Mar 2026 01:20:16 -0700 (PDT) Message-ID: <3c6851e3-247c-46fb-81f4-dcb2a39a5df8@redhat.com> Date: Thu, 12 Mar 2026 09:20:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 06/13] iov: Add IOV_PUT_HEADER() to write header data back to iov_tail To: David Gibson References: <20260309094744.1907754-1-lvivier@redhat.com> <20260309094744.1907754-7-lvivier@redhat.com> From: Laurent Vivier Autocrypt: addr=lvivier@redhat.com; keydata= xsFNBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABzSNMYXVyZW50IFZp dmllciA8bHZpdmllckByZWRoYXQuY29tPsLBeAQTAQIAIgUCVgVQgAIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQ8ww4vT8vvjwpgg//fSGy0Rs/t8cPFuzoY1cex4limJQfReLr SJXCANg9NOWy/bFK5wunj+h/RCFxIFhZcyXveurkBwYikDPUrBoBRoOJY/BHK0iZo7/WQkur 6H5losVZtrotmKOGnP/lJYZ3H6OWvXzdz8LL5hb3TvGOP68K8Bn8UsIaZJoeiKhaNR0sOJyI YYbgFQPWMHfVwHD/U+/gqRhD7apVysxv5by/pKDln1I5v0cRRH6hd8M8oXgKhF2+rAOL7gvh jEHSSWKUlMjC7YwwjSZmUkL+TQyE18e2XBk85X8Da3FznrLiHZFHQ/NzETYxRjnOzD7/kOVy gKD/o7asyWQVU65mh/ECrtjfhtCBSYmIIVkopoLaVJ/kEbVJQegT2P6NgERC/31kmTF69vn8 uQyW11Hk8tyubicByL3/XVBrq4jZdJW3cePNJbTNaT0d/bjMg5zCWHbMErUib2Nellnbg6bc 2HLDe0NLVPuRZhHUHM9hO/JNnHfvgiRQDh6loNOUnm9Iw2YiVgZNnT4soUehMZ7au8PwSl4I KYE4ulJ8RRiydN7fES3IZWmOPlyskp1QMQBD/w16o+lEtY6HSFEzsK3o0vuBRBVp2WKnssVH qeeV01ZHw0bvWKjxVNOksP98eJfWLfV9l9e7s6TaAeySKRRubtJ+21PRuYAxKsaueBfUE7ZT 7zfOwU0EVgUmGQEQALxSQRbl/QOnmssVDxWhHM5TGxl7oLNJms2zmBpcmlrIsn8nNz0rRyxT 460k2niaTwowSRK8KWVDeAW6ZAaWiYjLlTunoKwvF8vP3JyWpBz0diTxL5o+xpvy/Q6YU3BN efdq8Vy3rFsxgW7mMSrI/CxJ667y8ot5DVugeS2NyHfmZlPGE0Nsy7hlebS4liisXOrN3jFz asKyUws3VXek4V65lHwB23BVzsnFMn/bw/rPliqXGcwl8CoJu8dSyrCcd1Ibs0/Inq9S9+t0 VmWiQWfQkz4rvEeTQkp/VfgZ6z98JRW7S6l6eophoWs0/ZyRfOm+QVSqRfFZdxdP2PlGeIFM C3fXJgygXJkFPyWkVElr76JTbtSHsGWbt6xUlYHKXWo+xf9WgtLeby3cfSkEchACrxDrQpj+ Jt/JFP+q997dybkyZ5IoHWuPkn7uZGBrKIHmBunTco1+cKSuRiSCYpBIXZMHCzPgVDjk4viP brV9NwRkmaOxVvye0vctJeWvJ6KA7NoAURplIGCqkCRwg0MmLrfoZnK/gRqVJ/f6adhU1oo6 z4p2/z3PemA0C0ANatgHgBb90cd16AUxpdEQmOCmdNnNJF/3Zt3inzF+NFzHoM5Vwq6rc1JP jfC3oqRLJzqAEHBDjQFlqNR3IFCIAo4SYQRBdAHBCzkM4rWyRhuVABEBAAHCwV8EGAECAAkF AlYFJhkCGwwACgkQ8ww4vT8vvjwg9w//VQrcnVg3TsjEybxDEUBm8dBmnKqcnTBFmxN5FFtI WlEuY8+YMiWRykd8Ln9RJ/98/ghABHz9TN8TRo2b6WimV64FmlVn17Ri6FgFU3xNt9TTEChq AcNg88eYryKsYpFwegGpwUlaUaaGh1m9OrTzcQy+klVfZWaVJ9Nw0keoGRGb8j4XjVpL8+2x OhXKrM1fzzb8JtAuSbuzZSQPDwQEI5CKKxp7zf76J21YeRrEW4WDznPyVcDTa+tz++q2S/Bp P4W98bXCBIuQgs2m+OflERv5c3Ojldp04/S4NEjXEYRWdiCxN7ca5iPml5gLtuvhJMSy36gl U6IW9kn30IWuSoBpTkgV7rLUEhh9Ms82VWW/h2TxL8enfx40PrfbDtWwqRID3WY8jLrjKfTd R3LW8BnUDNkG+c4FzvvGUs8AvuqxxyHbXAfDx9o/jXfPHVRmJVhSmd+hC3mcQ+4iX5bBPBPM oDqSoLt5w9GoQQ6gDVP2ZjTWqwSRMLzNr37rJjZ1pt0DCMMTbiYIUcrhX8eveCJtY7NGWNyx FCRkhxRuGcpwPmRVDwOl39MB3iTsRighiMnijkbLXiKoJ5CDVvX5yicNqYJPKh5MFXN1bvsB kmYiStMRbrD0HoY1kx5/VozBtc70OU0EB8Wrv9hZD+Ofp0T3KOr1RUHvCZoLURfFhSQ= In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 6cJLsJC2jAxYzuFcSKtmqLTEoTrOSXrwkTliwqjK2zE_1773303618 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Message-ID-Hash: IC3ORPGD6XOABISDU66RRISUPUHYSYGQ X-Message-ID-Hash: IC3ORPGD6XOABISDU66RRISUPUHYSYGQ X-MailFrom: lvivier@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 3/12/26 05:12, David Gibson wrote: > On Mon, Mar 09, 2026 at 10:47:37AM +0100, Laurent Vivier wrote: >> Add a counterpart to IOV_PEEK_HEADER() that writes header data back >> to an iov_tail after modification. If the header pointer matches the >> original iov buffer location, it only advances the offset. Otherwise, >> it copies the data using iov_from_buf(). >> >> Signed-off-by: Laurent Vivier > > Reviewed-by: David Gibson > > Although a couple of thoughts on possible improvements below. > >> --- >> iov.c | 24 ++++++++++++++++++++++++ >> iov.h | 14 +++++++++++++- >> 2 files changed, 37 insertions(+), 1 deletion(-) >> >> diff --git a/iov.c b/iov.c >> index cd48667226f3..296f24b61067 100644 >> --- a/iov.c >> +++ b/iov.c >> @@ -305,6 +305,30 @@ void *iov_peek_header_(struct iov_tail *tail, void *v, size_t len, size_t align) >> return v; >> } >> >> +/** >> + * iov_put_header_() - Write header back to an IOV tail >> + * @tail: IOV tail to write header to >> + * @v: Pointer to header data to write >> + * @len: Length of header to write, in bytes >> + * >> + * Return: number of bytes written >> + */ >> +/* cppcheck-suppress unusedFunction */ >> +size_t iov_put_header_(struct iov_tail *tail, const void *v, size_t len) >> +{ >> + size_t l = len; >> + >> + /* iov_peek_header_() already called iov_check_header() */ >> + if ((char *)tail->iov[0].iov_base + tail->off != v) >> + l = iov_from_buf(tail->iov, tail->cnt, tail->off, v, len); > > This assumes the tail is already pruned. That will be the case > assuming this has a matching iov_peek_header_(), but it might be > better to explicitly document that assumption. > > Better yet, is there a way we could enforce these come in pairs. > Something like: > > struct some_header *hdr; > > with_header(hdr, tail) { > hdr->a = 123; > hdr->b = hdr->c - 7; > } > > Where, > #define with_header(hdr, tail) > for ((typeof *(hdr)) store, hdr = IOV_PEEK_HEADER(tail, store); > hdr; > IOV_PUT_HEADER(tail, hdr), hdr = NULL) > I really like the idea. Thanks, Laurent