From nobody Mon Feb 9 16:51:54 2026 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) (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 56180363C5F for ; Fri, 16 Jan 2026 11:01:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.168.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768561293; cv=none; b=CTBLPvXOETcsgCyMg0OJIdmYooyOh0aYkSEb1s2e6NStxzMi45V1OUh1eDQViYIx1sQTunu9o/Z6V5W096bGIBfHx+anwvcEtFgCMLQe6K/jj7dEdwxUzA6NDPE3u+YYO2lOS2ifEh2r56F9qNbtkBctGollsTkZdSi4o35lSc0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768561293; c=relaxed/simple; bh=d1cx1Jd/4DHrpoEbJF7oXxqIncKb9FPyclX3wr8K1fE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=JlPpWtwlXcuk7PFrgUx9DXDAo3JHh5zybrkkJaTlIkMmIzZbPYeOE3j2D4hZl3JuA2IFn4KuFTxqgP8zkdITlnr6tLxxn8ZGaiEbRhP8HKx8tjB41gR+N6t4+eoVt8rUzXPaBXdhWKWDZwdldGCEqgZpmuj+3IZdZShxKr6scqA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b=ERsjYknw; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b=asnCi+EG; arc=none smtp.client-ip=205.220.168.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b="ERsjYknw"; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b="asnCi+EG" Received: from pps.filterd (m0279867.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 60G86lWK3714357 for ; Fri, 16 Jan 2026 11:01:29 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=qcppdkim1; bh= CqdVwr7PjUV4mNOUzpcKLYJ1BwcKqgtV63blFChTZOs=; b=ERsjYknw+yyGTyvo Y2AiTPOJYIEGDpuc9QLcT201nuzTJiNJok8TN23CeZdLcuzfNhQvy+ZsXkqJUV6W LRQ4cW9EvoQ9gHFJfz9D10W4FNYkwE5ETbY+EdIkKHplCYwrHELZM1e1/b+kXqKD qM6XV2ThN+vzUSvrrqAeZGm2Smooimy04yfaIl41pAXSgFBh521IEoah1FDo7o8f K4Oqzo5daA3OWg4pcA7QcwDUEgIx4GffO2TdvkoalEjTczhX1/b3CJyQewmZrzE0 75oQPiVfL5u71C3TzRW2cFC4iMPtX7b0CQJKJf5QFmzxyaKWiRwjNirdCUG2p0sh JTtT9A== Received: from mail-qv1-f70.google.com (mail-qv1-f70.google.com [209.85.219.70]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4bq96p9vsm-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Fri, 16 Jan 2026 11:01:29 +0000 (GMT) Received: by mail-qv1-f70.google.com with SMTP id 6a1803df08f44-88fcbe2e351so74008316d6.1 for ; Fri, 16 Jan 2026 03:01:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1768561288; x=1769166088; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=CqdVwr7PjUV4mNOUzpcKLYJ1BwcKqgtV63blFChTZOs=; b=asnCi+EGxJOeENHCULDt1+Er48reU+QBakTL67Fm/EyYlRLXKQzjnPUhJabHdST952 5dJnmUd2Qn2WK1ltGWT6Bl31oxce0MQHmql7nmFWqt0YiAINK6DRN2fIArvWHqNpb3os WYwvRgg2H5O8/Ys8Brk0JfoSndS12GrtG+z4fGbuGAm6XL+LExmLmZm2zpvakmNz995K +BGnFpTGSWV/NhVq8cks2pd7+mg6SV5tGAzBRT2TDDJnwY4u43Dbn1/dge44KZjjzLob 7Vql3aZMGhXTGAHiuTvcs0rJRJ3KnBxMRJstWSopTdIX0QgZUdn7Dy2YMnoYizxu6Nwn Yx8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768561288; x=1769166088; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=CqdVwr7PjUV4mNOUzpcKLYJ1BwcKqgtV63blFChTZOs=; b=gDxiZ8M5c/MF96Ooocts8nxJWVCTMJfoIly2wK6iYghuQ78NgXAO30J8jAO26/Ytdi pDEACzzvujtXTe61cYkbel3x8OvFGnqxzDf8tFjkGi2xQ5wy/nvjzd1jap88hLw9A98L Houu1rjHSU3/PGXDffRy2+dhdDZte/QZsi4Ezw9WR8yYj+P/+Wj455A9WoBNqSLZy/UM ABOU0rwcs3XExCloBs1E7PqF6psiiDojHiAhfyUi6d3qNmNxw4X4VIEjiYWPOO6jGRlv 0x2freGy5tEPEFsg1G5uyVs98t5tQgflRi2zpMn3zXwrZsFqEWzPqzmcEJZHHAAvOJ+5 tpGw== X-Gm-Message-State: AOJu0YwyPx3tk3foBoqMtT8sH3NRSVgDoEEUvh11gnhp6FXMLIaI9Hjp q7PilDSbK7N5hks4v4BvEQvwFaEqTPAX1+faX29iMurWwLlmpDDCXIZEmlDwXT6g4Fvg3tK/PRQ JEbR0PDPT9J5ghbAWlxmEUPYm98ddsHlQlbxOWw4wfX4Kk9phCU7nWOdk+OLZuKDMq3s= X-Gm-Gg: AY/fxX7PK35JQN8KOYJGy4eHX+nYfN5YgEQlHKgtI5Fp5rFpSULtYnSv9BRRD15ZRuD Qnz1LNVbJWP56Az0DqBcEavOQAdgKU/3Z6Umfmnxg3XoS8j6oLdEhWsgtdbGcX4Iy+9+uJ030r2 xgI7lRyxz2UOUnBh533mczpZLO57d2POxyWvv7lngoI0VS/sxhEQ0XYiaztdAeE41uT5VspAlca IK1IUeOR5YDE+QH8sx9g2/L2lWHIZEfLLUSI7SSUhrMlL3FhDhDyIcrJ360F07HSjlexvMhLtRj 8XJkIo//eAZwoZK+rK1jWkGJMtlNlYLE5zRyf+XPYChT4FqahqaWJWazQniQ81osDVyTAm+TxtW aJ8Yk6ZaWYkThwRaLevdUiJPYYj9kTmgzsd1i+EY= X-Received: by 2002:a05:620a:254d:b0:8b2:63ae:6343 with SMTP id af79cd13be357-8c5919e232fmr843688185a.28.1768561287877; Fri, 16 Jan 2026 03:01:27 -0800 (PST) X-Received: by 2002:a05:620a:254d:b0:8b2:63ae:6343 with SMTP id af79cd13be357-8c5919e232fmr843680485a.28.1768561287263; Fri, 16 Jan 2026 03:01:27 -0800 (PST) Received: from brgl-qcom.local ([2a01:cb1d:dc:7e00:d1c:5bb0:db13:fc7d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47f4289b789sm93512975e9.1.2026.01.16.03.01.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Jan 2026 03:01:26 -0800 (PST) From: Bartosz Golaszewski Date: Fri, 16 Jan 2026 12:01:09 +0100 Subject: [PATCH 2/7] nvmem: return -EOPNOTSUPP to in-kernel users on missing callbacks Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260116-nvmem-unbind-v1-2-7bb401ab19a8@oss.qualcomm.com> References: <20260116-nvmem-unbind-v1-0-7bb401ab19a8@oss.qualcomm.com> In-Reply-To: <20260116-nvmem-unbind-v1-0-7bb401ab19a8@oss.qualcomm.com> To: Srinivas Kandagatla , Bartosz Golaszewski Cc: linux-kernel@vger.kernel.org, Bartosz Golaszewski X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=2920; i=bartosz.golaszewski@oss.qualcomm.com; h=from:subject:message-id; bh=d1cx1Jd/4DHrpoEbJF7oXxqIncKb9FPyclX3wr8K1fE=; b=owEBbQKS/ZANAwAKAQWdLsv/NoTDAcsmYgBpahp9RfFX2HQ+p0cu8IUBx3E8y81DQdNDGnkj8 5IOUhkd5HiJAjMEAAEKAB0WIQSR5RMt5bVGHXuiZfwFnS7L/zaEwwUCaWoafQAKCRAFnS7L/zaE w33oEACK2JwBfzKxUditM2zqg/b8UYy+l/Jg4RHjjE5D8Ys/TGl3pxNMPHmkmuxYTNsrAtVbdbg K2Gnc+5BsQpNeJb5mVuUE2qjQ1lVVNR1jCnMJcbv2EiEEnS+6u8BuhjW4dS9qWeDBDon+fS8Z3C 0qfQATooWDD49y5jNriWh/VE4Ke1WOKGucz+79VM7b/kyE4a8bb4j2I71auog3c9U3hgDKwxXD0 HPNdjSap0sQjO4APSdobI1+7K42FBr7+k3eCHwO0l6DLowOxDhm1RSya6dHMj5STCWASANu36rr y5k7V8sgjyOjmjqTRjdMMvKQEfsqSMFMYDZIW35HFTXDMlr8YUvxgOwcSNDi7tMlRRgzZ1Nws7K K5jJ1Vw75QHSoRTHql/f8xe3y9bHTAzVjJSBo32FDIla7dV/HkBwoKcvbcSiTyrVsiL5CkZPmYw lgNtNwB2P67I01QYIxMPS8Jy14Lgl79ShU8vCXsX/V5RATPEbkEMElnwzYT7mGqgj9pHXSJMgkl YFAGJrDn6jzZJfpmM1CD/A/xgKWGcXAtYuabmxwHbJcU0yDTY0YBFLukZIAoTRA6XEk1W+pG1C1 cpctEOhcP4WOJaSeAAPpbDSTcVT3UK8kFjjBj6X3Q/t2M9Zc5JK3h/Ohxwmoec0G3JeUxqjp1GN BQ6qb7dzde55xuw== X-Developer-Key: i=bartosz.golaszewski@oss.qualcomm.com; a=openpgp; fpr=169DEB6C0BC3C46013D2C79F11A72EA01471D772 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTE2MDA4MCBTYWx0ZWRfXwz53aELl+QtR SyUG6bwVzig6mXx1kNORpEKc5AGXOLHMRdwJJfmk9yhZQ0g3pXgu9f+tz96fBOqZ7VjP7SC2mug dhVVKzdu5bCH+bZTuscI3Ei8BBH/6DLARNSGzLGn1jcfkLZwpgn+GTeFK1/m72fwPQMnIOdm2h9 qDpMz2GTOBA00a24xu8BCifwSg3im7WVU8bC2Y2KzMufFVbmpD7HtHpCQPZsldQxqvvfQA8EqcX jmP36oIkiY+pE7nF6dEnfWqule1loHdVGHOwX8C27E5AIwlTdPXOhLgrpPtyY2d2r0vchnmz33l jIJs55SSI8zjo6ckw00KPHcxlKMD4Um0gGjRROKr638HRbm77iXf6oLoayxiVoF5+YS/BXve+3r QyzKy8JXgH68qk3DUU4V8puQKCJWLhkS6IlSmzxhNm4vGw7gm9GFojp9id+dlZ+k3Go/I20+VQP DN7qN3mtWZX4fgpwnvQ== X-Authority-Analysis: v=2.4 cv=M7ZA6iws c=1 sm=1 tr=0 ts=696a1a89 cx=c_pps a=oc9J++0uMp73DTRD5QyR2A==:117 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=vUbySO9Y5rIA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=EUspDBNiAAAA:8 a=fMUuWMZ6TpuTS4Z4e9kA:9 a=QEXdDO2ut3YA:10 a=iYH6xdkBrDN1Jqds4HTS:22 X-Proofpoint-GUID: YnBjtdRAU6T0llrwT3js9djbViH5gppP X-Proofpoint-ORIG-GUID: YnBjtdRAU6T0llrwT3js9djbViH5gppP X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2026-01-16_03,2026-01-15_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 malwarescore=0 suspectscore=0 adultscore=0 spamscore=0 phishscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2512120000 definitions=main-2601160080 __nvmem_reg_read/write() currently return -EINVAL if the relevant callback is not present. User-space helpers again check the presence of the callbacks to see if they should return -EPERM. Ahead of adding SRCU synchronization: change the error code returned to in-kernel users to -EOPNOTSUPP which is more indicative of the actual reason for the failure as well as allows us to translate it easily to -EPERM in sysfs callbacks without having to dereference the callback pointers. This will allow us to limit the number of SRCU critical sections in the follow-up commits. Signed-off-by: Bartosz Golaszewski --- drivers/nvmem/core.c | 37 +++++++++++++++++++------------------ 1 file changed, 19 insertions(+), 18 deletions(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 387c88c55259541446901f0e539bbb0dd8c4c3de..c4a5f8ef65164ef6994343e6d26= d3d302c9b00c3 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -55,10 +55,10 @@ static BLOCKING_NOTIFIER_HEAD(nvmem_notifier); static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offse= t, void *val, size_t bytes) { - if (nvmem->reg_read) - return nvmem->reg_read(nvmem->priv, offset, val, bytes); + if (!nvmem->reg_read) + return -EOPNOTSUPP; =20 - return -EINVAL; + return nvmem->reg_read(nvmem->priv, offset, val, bytes); } =20 static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offs= et, @@ -66,14 +66,14 @@ static int __nvmem_reg_write(struct nvmem_device *nvmem= , unsigned int offset, { int ret; =20 - if (nvmem->reg_write) { - gpiod_set_value_cansleep(nvmem->wp_gpio, 0); - ret =3D nvmem->reg_write(nvmem->priv, offset, val, bytes); - gpiod_set_value_cansleep(nvmem->wp_gpio, 1); - return ret; - } + if (!nvmem->reg_write) + return -EOPNOTSUPP; + + gpiod_set_value_cansleep(nvmem->wp_gpio, 0); + ret =3D nvmem->reg_write(nvmem->priv, offset, val, bytes); + gpiod_set_value_cansleep(nvmem->wp_gpio, 1); =20 - return -EINVAL; + return ret; } =20 static int nvmem_access_with_keepouts(struct nvmem_device *nvmem, @@ -231,13 +231,12 @@ static ssize_t bin_attr_nvmem_read(struct file *filp,= struct kobject *kobj, =20 count =3D round_down(count, nvmem->word_size); =20 - if (!nvmem->reg_read) - return -EPERM; - rc =3D nvmem_reg_read(nvmem, pos, buf, count); - - if (rc) + if (rc) { + if (rc =3D=3D -EOPNOTSUPP) + rc =3D -EPERM; return rc; + } =20 return count; } @@ -264,13 +263,15 @@ static ssize_t bin_attr_nvmem_write(struct file *filp= , struct kobject *kobj, =20 count =3D round_down(count, nvmem->word_size); =20 - if (!nvmem->reg_write || nvmem->read_only) + if (nvmem->read_only) return -EPERM; =20 rc =3D nvmem_reg_write(nvmem, pos, buf, count); - - if (rc) + if (rc) { + if (rc =3D=3D -EOPNOTSUPP) + rc =3D -EPERM; return rc; + } =20 return count; } --=20 2.47.3