From nobody Sat Apr 4 06:05:57 2026 Received: from mail-dy1-f226.google.com (mail-dy1-f226.google.com [74.125.82.226]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 666D135A3A2 for ; Fri, 20 Mar 2026 20:33:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.226 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774038838; cv=none; b=D1GMkKfHhQwVrZYkzOQNV7VFF7++0Snm3wYbNo9aoSrj/euGilKvkcP9wcbqaaeA9K4LVW7Hj/Ylq0ejDmUFNBVsoZNXdfGUdachLzJl/ggBZkYqw1ohSIXM1efawXBjDv8HztK9mcyzwwicEEnpv9OvDAkB0LbMbd0TTyyYZD4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774038838; c=relaxed/simple; bh=7AmnG/UUYqW9PbgLMpQCGJh+iAZg56GN9U6BhFeGBjM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=BQRizPCC5mzwUP3FtO/wFwicGxoG4tnpfmjph43bX9xKINOFFUZToKXhMudUqkbGiyY/w0fjPh67b32XXxisTdPcGxa/cUTLjmmaKZEpckHwdBo58CfdWooEoEd4HKz4p4f7jns2NXzuK+STqgEU6aoBx+biyG6fbeQ62/DwVS0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com; spf=fail smtp.mailfrom=broadcom.com; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b=JahlS7dQ; arc=none smtp.client-ip=74.125.82.226 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=broadcom.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="JahlS7dQ" Received: by mail-dy1-f226.google.com with SMTP id 5a478bee46e88-2b6b0500e06so2665377eec.1 for ; Fri, 20 Mar 2026 13:33:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774038835; x=1774643635; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=2eHxZs/jSCBES4akkCBqfFi+qs+gICn2xClTm9J1Alg=; b=MkBASlCtUHVuRjbeECv9DUMjczs/WDVJZXrFW8rCZLft/6HOTg8jdtgiT1IOJTqnJ1 Pbl24TjTcJVz3ISy9Do6Pwhle8umqTJM3r71/entEWWhmWEUv19Ho4yUTLJ0cHHr038K Cwzh3hEIp1gu55VLJVAZe3Sbpy1FGNzoZrcBneEfz0ufMuEQr3XGKab1ePtSEePevvxS Q4C5aFg6+FeDBul6HRkhzbKE5mly1VKRH61dY9GFzHWv+ipKHSQBbaqKMFpfz4dNQPzJ /J2dmwcO57nGiO9tA38Qv/srmuMGribjgE7B/Ha6F7b+RtjzQecKWrjjRH2JStEQNuZ/ YuYQ== X-Forwarded-Encrypted: i=1; AJvYcCXE7vjeKlqMSFyLrgJMBlWW6gvO9T6rrFpKWELvDEz0vmRDT5TkIUUxmMK8v8BZkLiGqbX0tCBLJcuahfc=@vger.kernel.org X-Gm-Message-State: AOJu0YwbuxtM2hC3QFFQaN+MvHiMM3QhpK5bkjFhpJ1AireBSo3DJmuo rk18qw5AIMbkXAxf2i9aqrhIpuQcBx9xUBOF0ToVeaceGgNotXADRt4gZOkCL2bP5FPlKGG6qUJ Ko3CQPVzZwKTgaIQ+u/eoOqRz0noRbHUaIOEVbjQkcOS3n2glSqhs9p6CrMn25XQAlAvMed5rLc fCAvmpDKs9xxA8E2SJn2AgdOImKrm6PTGIueP+3sM+E14CVj2ewO/Lex8UH5a3NwglyDkNtnxYz lztAsrfLbdgiLVE X-Gm-Gg: ATEYQzynH8NqibLDBKWOn7/qfqQBy4lFRzRHVDulIw/A+Cd4Q7B/HPAUjQjnG7JFnxy XWJHOr8dRbsje9JB1bh0U2fBNMvfBkGd/vWeVEG3gsHOpXHrtR1XgeOMQHnPtGZwXjY8F+k9png QdWgcz6pCztH1OGkYssdeVKghV6gB6zHiRKnW9VWg1zHNPYCCYaBAT+BD1OhYyID4PMjKpXigUc DJSHKXr0MR+JHwdDgD3WrdBBWsmeU6TEpLYIamSGPUBMLVcfBF/NDecJcrZSTMHvdJGuhaZUMJr TW4r2Tkrh0sygp0W4OU9eCVGQ73CFbtyB8kpNZcvTVF50wVBox11T+FoxYQD48gsP5ws0Wt9kb+ n+xarge5U/OfgUmLC9EUesA0y+6CpmLFl5+6AL7UjszJ19F7ILgQiEKj3Wo0Sz7Qc3gcy8L49DA UAwrukQ2VPKT8HlINga0UYUW6NXzG8xIUuOwQlXRNecNa4IxSuYGTfv+VS X-Received: by 2002:a05:693c:2c0f:b0:2b8:26b8:3446 with SMTP id 5a478bee46e88-2c1095a75e9mr1826562eec.2.1774038835269; Fri, 20 Mar 2026 13:33:55 -0700 (PDT) Received: from smtp-us-east1-p01-i01-si01.dlp.protect.broadcom.com (address-144-49-247-117.dlp.protect.broadcom.com. [144.49.247.117]) by smtp-relay.gmail.com with ESMTPS id 5a478bee46e88-2c10b162b62sm282324eec.4.2026.03.20.13.33.55 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Mar 2026 13:33:55 -0700 (PDT) X-Relaying-Domain: broadcom.com X-CFilter-Loop: Reflected Received: by mail-qk1-f197.google.com with SMTP id af79cd13be357-8cd7f6ac239so1386508485a.2 for ; Fri, 20 Mar 2026 13:33:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1774038834; x=1774643634; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2eHxZs/jSCBES4akkCBqfFi+qs+gICn2xClTm9J1Alg=; b=JahlS7dQmL4FYrMG7cgqa8qH81d8VeQRG6ptcM6Cu6wKLLf7zECqyTNxuQWSZfacAp 3tUGx9BnwWAdGz3VUloJwPz1pWv0LiK8FGcJEpE5VhOftqYurnHkE1mU7RZrYrkd9u/B 4ZhOeq5ybz4LXtRtI15K13mif/wH1C69z4yXI= X-Forwarded-Encrypted: i=1; AJvYcCWY2TX0ce+aSdHMk7+1B1uX72KIQNohpUSl6eZ4t/r6GppWRAw6bANGjN+35G2hm2aUomXeGzxNO/E9uAI=@vger.kernel.org X-Received: by 2002:a05:620a:4487:b0:8cd:97de:bb52 with SMTP id af79cd13be357-8cfc7e71174mr640561185a.22.1774038828694; Fri, 20 Mar 2026 13:33:48 -0700 (PDT) X-Received: by 2002:a05:620a:4487:b0:8cd:97de:bb52 with SMTP id af79cd13be357-8cfc7e71174mr640556185a.22.1774038828133; Fri, 20 Mar 2026 13:33:48 -0700 (PDT) Received: from mail.broadcom.net ([192.19.144.250]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cfc8fb9c10sm280699985a.19.2026.03.20.13.33.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Mar 2026 13:33:47 -0700 (PDT) From: Kamal Dasu To: Ulf Hansson , Adrian Hunter , Kees Cook Cc: Tony Luck , "Guilherme G . Piccoli" , Florian Fainelli , Arend van Spriel , William Zhang , bcm-kernel-feedback-list@broadcom.com, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Kamal Dasu Subject: [PATCH v4 3/4] mmc: block: Add helper to look up mmc_card by device name Date: Fri, 20 Mar 2026 16:32:48 -0400 Message-Id: <20260320203249.1965044-4-kamal.dasu@broadcom.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260320203249.1965044-1-kamal.dasu@broadcom.com> References: <20260320203249.1965044-1-kamal.dasu@broadcom.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e Content-Type: text/plain; charset="utf-8" Add mmc_blk_get_card_by_name() which resolves an MMC block device name (e.g., "mmcblk1") to its associated struct mmc_card by opening the block device and traversing gendisk to the mmc_blk_data private data. This is needed by the mmcpstore backend driver to find the card associated with a given pstore_blk block device path. When mmcpstore is built as a module, the eMMC card is already probed by the time the module loads, so the helper can look it up directly. Signed-off-by: Kamal Dasu --- drivers/mmc/core/block.c | 54 ++++++++++++++++++++++++++++++++++++++++ drivers/mmc/core/block.h | 4 +++ 2 files changed, 58 insertions(+) diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 05ee76cb0a08..91e3a778d5b2 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -3441,6 +3441,60 @@ static void __exit mmc_blk_exit(void) bus_unregister(&mmc_rpmb_bus_type); } =20 +/** + * mmc_blk_get_card_by_name - Get mmc_card from device name + * @device_name: Name of the MMC device (e.g., "mmcblk1") + * + * Resolves an MMC block device name to its associated struct mmc_card. + * Used by the mmcpstore backend driver (when built as a module) to find + * the card associated with a given pstore_blk block device path. + * + * Returns: mmc_card pointer on success, NULL on failure + */ +struct mmc_card *mmc_blk_get_card_by_name(const char *device_name) +{ + struct file *bdev_file; + struct block_device *bdev; + struct gendisk *disk; + struct mmc_blk_data *md; + struct mmc_card *card =3D NULL; + char dev_path[32]; + + if (!device_name) + return NULL; + + snprintf(dev_path, sizeof(dev_path), "/dev/%s", device_name); + + bdev_file =3D bdev_file_open_by_path(dev_path, BLK_OPEN_READ, NULL, NULL); + if (IS_ERR(bdev_file)) { + pr_debug("mmc_blk: Failed to open block device %s: %ld\n", + dev_path, PTR_ERR(bdev_file)); + return NULL; + } + bdev =3D file_bdev(bdev_file); + + disk =3D bdev->bd_disk; + if (!disk) { + pr_err("mmc_blk: No gendisk found for %s\n", dev_path); + goto out_put_bdev; + } + + md =3D disk->private_data; + if (!md) { + pr_debug("mmc_blk: No mmc_blk_data found for %s\n", dev_path); + goto out_put_bdev; + } + + card =3D md->queue.card; + if (!card) + pr_err("mmc_blk: No mmc_card found for %s\n", dev_path); + +out_put_bdev: + fput(bdev_file); + return card; +} +EXPORT_SYMBOL_GPL(mmc_blk_get_card_by_name); + module_init(mmc_blk_init); module_exit(mmc_blk_exit); =20 diff --git a/drivers/mmc/core/block.h b/drivers/mmc/core/block.h index 31153f656f41..08798c56dcce 100644 --- a/drivers/mmc/core/block.h +++ b/drivers/mmc/core/block.h @@ -17,4 +17,8 @@ struct work_struct; =20 void mmc_blk_mq_complete_work(struct work_struct *work); =20 +/* MMC block device helper for mmcpstore */ +struct mmc_card; +struct mmc_card *mmc_blk_get_card_by_name(const char *device_name); + #endif --=20 2.34.1