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[144.49.247.102]) by smtp-relay.gmail.com with ESMTPS id 6a1803df08f44-89c852f31e5sm286256d6.24.2026.03.19.11.59.57 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Mar 2026 11:59:57 -0700 (PDT) X-Relaying-Domain: broadcom.com X-CFilter-Loop: Reflected Received: by mail-dy1-f198.google.com with SMTP id 5a478bee46e88-2bdc1b30ac8so23455039eec.1 for ; Thu, 19 Mar 2026 11:59:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1773946796; x=1774551596; 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=DuAwCXcI6dN/8lLmN22NPMdicBkDgCb3cStVa8sCCf3r1RmsXfEkjWtFPXR+qwUYl1 1bEcF2+fQkMB8jadTGfQmy9YPRN24oDsWruQep+KJH+4TJbh9c/Y5W+oRk/RHLsOkgAQ hholXVPyD04cksw+34IIb9a7cN+WmYTuS3LfQ= X-Forwarded-Encrypted: i=1; AJvYcCUgOgHD6EzraBUiZ8wXeydbA9d0CLe5TktMpOcLGMO7gFkYoldETK34f8xp/yVpN86CfioNue7KxGFMEUg=@vger.kernel.org X-Received: by 2002:a05:693c:2c13:b0:2ba:7875:10c9 with SMTP id 5a478bee46e88-2c109760e2dmr255819eec.26.1773946796133; Thu, 19 Mar 2026 11:59:56 -0700 (PDT) X-Received: by 2002:a05:693c:2c13:b0:2ba:7875:10c9 with SMTP id 5a478bee46e88-2c109760e2dmr255795eec.26.1773946795468; Thu, 19 Mar 2026 11:59:55 -0700 (PDT) Received: from mail.broadcom.net ([192.19.144.250]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2c0e55834a0sm9607220eec.14.2026.03.19.11.59.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Mar 2026 11:59:55 -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 v3 3/4] mmc: block: Add helper to look up mmc_card by device name Date: Thu, 19 Mar 2026 14:57:04 -0400 Message-Id: <20260319185705.1516950-4-kamal.dasu@broadcom.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260319185705.1516950-1-kamal.dasu@broadcom.com> References: <20260319185705.1516950-1-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