block: move the code to do early boot lookup of block devices to block/
Create a new block/early-lookup.c to keep the early block device lookup code instead of having this code sit with the early mount code. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230531125535.676098-16-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig
Jens Axboe
parent
079caa35f7
commit
702f3189e4
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@ -5453,8 +5453,8 @@
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root= [KNL] Root filesystem
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Usually this a a block device specifier of some kind,
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see the early_lookup_bdev comment in init/do_mounts.c
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for details.
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see the early_lookup_bdev comment in
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block/early-lookup.c for details.
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Alternatively this can be "ram" for the legacy initial
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ramdisk, "nfs" and "cifs" for root on a network file
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system, or "mtd" and "ubi" for mounting from raw flash.
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@ -9,7 +9,7 @@ obj-y := bdev.o fops.o bio.o elevator.o blk-core.o blk-sysfs.o \
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blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \
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blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \
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genhd.o ioprio.o badblocks.o partitions/ blk-rq-qos.o \
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disk-events.o blk-ia-ranges.o
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disk-events.o blk-ia-ranges.o early-lookup.o
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obj-$(CONFIG_BOUNCE) += bounce.o
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obj-$(CONFIG_BLK_DEV_BSG_COMMON) += bsg.o
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@ -0,0 +1,224 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Code for looking up block devices in the early boot code before mounting the
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* root file system. Unfortunately currently also abused in a few other places.
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*/
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#include <linux/blkdev.h>
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#include <linux/ctype.h>
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struct uuidcmp {
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const char *uuid;
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int len;
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};
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/**
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* match_dev_by_uuid - callback for finding a partition using its uuid
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* @dev: device passed in by the caller
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* @data: opaque pointer to the desired struct uuidcmp to match
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*
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* Returns 1 if the device matches, and 0 otherwise.
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*/
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static int match_dev_by_uuid(struct device *dev, const void *data)
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{
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struct block_device *bdev = dev_to_bdev(dev);
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const struct uuidcmp *cmp = data;
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if (!bdev->bd_meta_info ||
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strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len))
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return 0;
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return 1;
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}
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/**
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* devt_from_partuuid - looks up the dev_t of a partition by its UUID
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* @uuid_str: char array containing ascii UUID
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*
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* The function will return the first partition which contains a matching
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* UUID value in its partition_meta_info struct. This does not search
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* by filesystem UUIDs.
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*
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* If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
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* extracted and used as an offset from the partition identified by the UUID.
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*
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* Returns the matching dev_t on success or 0 on failure.
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*/
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static int devt_from_partuuid(const char *uuid_str, dev_t *devt)
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{
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struct uuidcmp cmp;
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struct device *dev = NULL;
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int offset = 0;
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char *slash;
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cmp.uuid = uuid_str;
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slash = strchr(uuid_str, '/');
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/* Check for optional partition number offset attributes. */
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if (slash) {
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char c = 0;
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/* Explicitly fail on poor PARTUUID syntax. */
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if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
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goto out_invalid;
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cmp.len = slash - uuid_str;
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} else {
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cmp.len = strlen(uuid_str);
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}
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if (!cmp.len)
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goto out_invalid;
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dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
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if (!dev)
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return -ENODEV;
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if (offset) {
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/*
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* Attempt to find the requested partition by adding an offset
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* to the partition number found by UUID.
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*/
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*devt = part_devt(dev_to_disk(dev),
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dev_to_bdev(dev)->bd_partno + offset);
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} else {
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*devt = dev->devt;
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}
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put_device(dev);
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return 0;
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out_invalid:
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pr_err("VFS: PARTUUID= is invalid.\n"
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"Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
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return -EINVAL;
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}
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/**
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* match_dev_by_label - callback for finding a partition using its label
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* @dev: device passed in by the caller
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* @data: opaque pointer to the label to match
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*
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* Returns 1 if the device matches, and 0 otherwise.
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*/
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static int match_dev_by_label(struct device *dev, const void *data)
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{
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struct block_device *bdev = dev_to_bdev(dev);
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const char *label = data;
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if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname))
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return 0;
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return 1;
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}
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static int devt_from_partlabel(const char *label, dev_t *devt)
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{
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struct device *dev;
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dev = class_find_device(&block_class, NULL, label, &match_dev_by_label);
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if (!dev)
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return -ENODEV;
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*devt = dev->devt;
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put_device(dev);
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return 0;
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}
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static int devt_from_devname(const char *name, dev_t *devt)
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{
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int part;
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char s[32];
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char *p;
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if (strlen(name) > 31)
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return -EINVAL;
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strcpy(s, name);
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for (p = s; *p; p++) {
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if (*p == '/')
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*p = '!';
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}
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*devt = blk_lookup_devt(s, 0);
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if (*devt)
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return 0;
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/*
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* Try non-existent, but valid partition, which may only exist after
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* opening the device, like partitioned md devices.
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*/
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while (p > s && isdigit(p[-1]))
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p--;
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if (p == s || !*p || *p == '0')
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return -EINVAL;
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/* try disk name without <part number> */
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part = simple_strtoul(p, NULL, 10);
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*p = '\0';
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*devt = blk_lookup_devt(s, part);
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if (*devt)
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return 0;
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/* try disk name without p<part number> */
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if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
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return -EINVAL;
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p[-1] = '\0';
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*devt = blk_lookup_devt(s, part);
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if (*devt)
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return 0;
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return -EINVAL;
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}
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static int devt_from_devnum(const char *name, dev_t *devt)
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{
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unsigned maj, min, offset;
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char *p, dummy;
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if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
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sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) {
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*devt = MKDEV(maj, min);
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if (maj != MAJOR(*devt) || min != MINOR(*devt))
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return -EINVAL;
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} else {
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*devt = new_decode_dev(simple_strtoul(name, &p, 16));
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if (*p)
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return -EINVAL;
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}
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return 0;
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}
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/*
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* Convert a name into device number. We accept the following variants:
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*
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* 1) <hex_major><hex_minor> device number in hexadecimal represents itself
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* no leading 0x, for example b302.
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* 3) /dev/<disk_name> represents the device number of disk
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* 4) /dev/<disk_name><decimal> represents the device number
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* of partition - device number of disk plus the partition number
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* 5) /dev/<disk_name>p<decimal> - same as the above, that form is
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* used when disk name of partitioned disk ends on a digit.
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* 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
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* unique id of a partition if the partition table provides it.
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* The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
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* partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
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* filled hex representation of the 32-bit "NT disk signature", and PP
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* is a zero-filled hex representation of the 1-based partition number.
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* 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
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* a partition with a known unique id.
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* 8) <major>:<minor> major and minor number of the device separated by
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* a colon.
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* 9) PARTLABEL=<name> with name being the GPT partition label.
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* MSDOS partitions do not support labels!
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*
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* If name doesn't have fall into the categories above, we return (0,0).
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* block_class is used to check if something is a disk name. If the disk
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* name contains slashes, the device name has them replaced with
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* bangs.
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*/
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int early_lookup_bdev(const char *name, dev_t *devt)
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{
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if (strncmp(name, "PARTUUID=", 9) == 0)
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return devt_from_partuuid(name + 9, devt);
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if (strncmp(name, "PARTLABEL=", 10) == 0)
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return devt_from_partlabel(name + 10, devt);
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if (strncmp(name, "/dev/", 5) == 0)
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return devt_from_devname(name + 5, devt);
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return devt_from_devnum(name, devt);
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}
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EXPORT_SYMBOL_GPL(early_lookup_bdev);
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219
init/do_mounts.c
219
init/do_mounts.c
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@ -59,225 +59,6 @@ static int __init readwrite(char *str)
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__setup("ro", readonly);
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__setup("rw", readwrite);
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#ifdef CONFIG_BLOCK
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struct uuidcmp {
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const char *uuid;
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int len;
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};
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/**
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* match_dev_by_uuid - callback for finding a partition using its uuid
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* @dev: device passed in by the caller
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* @data: opaque pointer to the desired struct uuidcmp to match
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*
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* Returns 1 if the device matches, and 0 otherwise.
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*/
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static int match_dev_by_uuid(struct device *dev, const void *data)
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{
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struct block_device *bdev = dev_to_bdev(dev);
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const struct uuidcmp *cmp = data;
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if (!bdev->bd_meta_info ||
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strncasecmp(cmp->uuid, bdev->bd_meta_info->uuid, cmp->len))
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return 0;
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return 1;
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}
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/**
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* devt_from_partuuid - looks up the dev_t of a partition by its UUID
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* @uuid_str: char array containing ascii UUID
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*
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* The function will return the first partition which contains a matching
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* UUID value in its partition_meta_info struct. This does not search
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* by filesystem UUIDs.
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*
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* If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
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* extracted and used as an offset from the partition identified by the UUID.
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*
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* Returns the matching dev_t on success or 0 on failure.
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*/
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static int devt_from_partuuid(const char *uuid_str, dev_t *devt)
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{
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struct uuidcmp cmp;
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struct device *dev = NULL;
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int offset = 0;
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char *slash;
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cmp.uuid = uuid_str;
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slash = strchr(uuid_str, '/');
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/* Check for optional partition number offset attributes. */
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if (slash) {
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char c = 0;
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/* Explicitly fail on poor PARTUUID syntax. */
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if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1)
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goto out_invalid;
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cmp.len = slash - uuid_str;
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} else {
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cmp.len = strlen(uuid_str);
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}
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if (!cmp.len)
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goto out_invalid;
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dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid);
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if (!dev)
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return -ENODEV;
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if (offset) {
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/*
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* Attempt to find the requested partition by adding an offset
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* to the partition number found by UUID.
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*/
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*devt = part_devt(dev_to_disk(dev),
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dev_to_bdev(dev)->bd_partno + offset);
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} else {
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*devt = dev->devt;
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}
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put_device(dev);
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return 0;
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out_invalid:
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pr_err("VFS: PARTUUID= is invalid.\n"
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"Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
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return -EINVAL;
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}
|
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|
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/**
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* match_dev_by_label - callback for finding a partition using its label
|
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* @dev: device passed in by the caller
|
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* @data: opaque pointer to the label to match
|
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*
|
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* Returns 1 if the device matches, and 0 otherwise.
|
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*/
|
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static int match_dev_by_label(struct device *dev, const void *data)
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{
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struct block_device *bdev = dev_to_bdev(dev);
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const char *label = data;
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if (!bdev->bd_meta_info || strcmp(label, bdev->bd_meta_info->volname))
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return 0;
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return 1;
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}
|
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|
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static int devt_from_partlabel(const char *label, dev_t *devt)
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{
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struct device *dev;
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|
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dev = class_find_device(&block_class, NULL, label, &match_dev_by_label);
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if (!dev)
|
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return -ENODEV;
|
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*devt = dev->devt;
|
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put_device(dev);
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return 0;
|
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}
|
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|
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static int devt_from_devname(const char *name, dev_t *devt)
|
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{
|
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int part;
|
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char s[32];
|
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char *p;
|
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|
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if (strlen(name) > 31)
|
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return -EINVAL;
|
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strcpy(s, name);
|
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for (p = s; *p; p++) {
|
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if (*p == '/')
|
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*p = '!';
|
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}
|
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|
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*devt = blk_lookup_devt(s, 0);
|
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if (*devt)
|
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return 0;
|
||||
|
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/*
|
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* Try non-existent, but valid partition, which may only exist after
|
||||
* opening the device, like partitioned md devices.
|
||||
*/
|
||||
while (p > s && isdigit(p[-1]))
|
||||
p--;
|
||||
if (p == s || !*p || *p == '0')
|
||||
return -EINVAL;
|
||||
|
||||
/* try disk name without <part number> */
|
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part = simple_strtoul(p, NULL, 10);
|
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*p = '\0';
|
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*devt = blk_lookup_devt(s, part);
|
||||
if (*devt)
|
||||
return 0;
|
||||
|
||||
/* try disk name without p<part number> */
|
||||
if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
|
||||
return -EINVAL;
|
||||
p[-1] = '\0';
|
||||
*devt = blk_lookup_devt(s, part);
|
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if (*devt)
|
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return 0;
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
static int devt_from_devnum(const char *name, dev_t *devt)
|
||||
{
|
||||
unsigned maj, min, offset;
|
||||
char *p, dummy;
|
||||
|
||||
if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 ||
|
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sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) {
|
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*devt = MKDEV(maj, min);
|
||||
if (maj != MAJOR(*devt) || min != MINOR(*devt))
|
||||
return -EINVAL;
|
||||
} else {
|
||||
*devt = new_decode_dev(simple_strtoul(name, &p, 16));
|
||||
if (*p)
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Convert a name into device number. We accept the following variants:
|
||||
*
|
||||
* 1) <hex_major><hex_minor> device number in hexadecimal represents itself
|
||||
* no leading 0x, for example b302.
|
||||
* 3) /dev/<disk_name> represents the device number of disk
|
||||
* 4) /dev/<disk_name><decimal> represents the device number
|
||||
* of partition - device number of disk plus the partition number
|
||||
* 5) /dev/<disk_name>p<decimal> - same as the above, that form is
|
||||
* used when disk name of partitioned disk ends on a digit.
|
||||
* 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
|
||||
* unique id of a partition if the partition table provides it.
|
||||
* The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
|
||||
* partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
|
||||
* filled hex representation of the 32-bit "NT disk signature", and PP
|
||||
* is a zero-filled hex representation of the 1-based partition number.
|
||||
* 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
|
||||
* a partition with a known unique id.
|
||||
* 8) <major>:<minor> major and minor number of the device separated by
|
||||
* a colon.
|
||||
* 9) PARTLABEL=<name> with name being the GPT partition label.
|
||||
* MSDOS partitions do not support labels!
|
||||
*
|
||||
* If name doesn't have fall into the categories above, we return (0,0).
|
||||
* block_class is used to check if something is a disk name. If the disk
|
||||
* name contains slashes, the device name has them replaced with
|
||||
* bangs.
|
||||
*/
|
||||
int early_lookup_bdev(const char *name, dev_t *devt)
|
||||
{
|
||||
if (strncmp(name, "PARTUUID=", 9) == 0)
|
||||
return devt_from_partuuid(name + 9, devt);
|
||||
if (strncmp(name, "PARTLABEL=", 10) == 0)
|
||||
return devt_from_partlabel(name + 10, devt);
|
||||
if (strncmp(name, "/dev/", 5) == 0)
|
||||
return devt_from_devname(name + 5, devt);
|
||||
return devt_from_devnum(name, devt);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(early_lookup_bdev);
|
||||
#endif
|
||||
|
||||
static int __init root_dev_setup(char *line)
|
||||
{
|
||||
strscpy(saved_root_name, line, sizeof(saved_root_name));
|
||||
|
|
|
|||
Loading…
Reference in New Issue