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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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bad6663f24
This is a wrap-up of three patches pending upstream approval. I'm bundling them because they are interdependent, and it'll be easier to drop it on rebase later. 1. dm: allow a dm-fs-style device to be shared via dm-ioctl Integrates feedback from Alisdair, Mike, and Kiyoshi. Two main changes occur here: - One function is added which allows for a programmatically created mapped device to be inserted into the dm-ioctl hash table. This binds the device to a name and, optional, uuid which is needed by udev and allows for userspace management of the mapped device. - dm_table_complete() was extended to handle all of the final functional changes required for the table to be operational once called. 2. init: boot to device-mapper targets without an initr* Add a dm= kernel parameter modeled after the md= parameter from do_mounts_md. It allows for device-mapper targets to be configured at boot time for use early in the boot process (as the root device or otherwise). It also replaces /dev/XXX calls with major:minor opportunistically. The format is dm="name uuid ro,table line 1,table line 2,...". The parser expects the comma to be safe to use as a newline substitute but, otherwise, uses the normal separator of space. Some attempt has been made to make it forgiving of additional spaces (using skip_spaces()). A mapped device created during boot will be assigned a minor of 0 and may be access via /dev/dm-0. An example dm-linear root with no uuid may look like: root=/dev/dm-0 dm="lroot none ro, 0 4096 linear /dev/ubdb 0, 4096 4096 linear /dv/ubdc 0" Once udev is started, /dev/dm-0 will become /dev/mapper/lroot. Older upstream threads: http://marc.info/?l=dm-devel&m=127429492521964&w=2 http://marc.info/?l=dm-devel&m=127429499422096&w=2 http://marc.info/?l=dm-devel&m=127429493922000&w=2 Latest upstream threads: https://patchwork.kernel.org/patch/104859/ https://patchwork.kernel.org/patch/104860/ https://patchwork.kernel.org/patch/104861/ BUG: 27175947 Signed-off-by: Will Drewry <wad@chromium.org> Review URL: http://codereview.chromium.org/2020011 Change-Id: I92bd53432a11241228d2e5ac89a3b20d19b05a31
410 lines
9.8 KiB
C
410 lines
9.8 KiB
C
/* do_mounts_dm.c
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* Copyright (C) 2010 The Chromium OS Authors <chromium-os-dev@chromium.org>
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* All Rights Reserved.
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* Based on do_mounts_md.c
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*
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* This file is released under the GPL.
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*/
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#include <linux/device-mapper.h>
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#include <linux/fs.h>
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#include <linux/string.h>
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#include "do_mounts.h"
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#define DM_MAX_NAME 32
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#define DM_MAX_UUID 129
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#define DM_NO_UUID "none"
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#define DM_MSG_PREFIX "init"
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/* Separators used for parsing the dm= argument. */
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#define DM_FIELD_SEP ' '
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#define DM_LINE_SEP ','
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/*
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* When the device-mapper and any targets are compiled into the kernel
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* (not a module), one target may be created and used as the root device at
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* boot time with the parameters given with the boot line dm=...
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* The code for that is here.
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*/
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struct dm_setup_target {
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sector_t begin;
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sector_t length;
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char *type;
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char *params;
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/* simple singly linked list */
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struct dm_setup_target *next;
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};
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static struct {
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int minor;
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int ro;
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char name[DM_MAX_NAME];
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char uuid[DM_MAX_UUID];
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char *targets;
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struct dm_setup_target *target;
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int target_count;
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} dm_setup_args __initdata;
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static __initdata int dm_early_setup;
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static size_t __init get_dm_option(char *str, char **next, char sep)
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{
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size_t len = 0;
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char *endp = NULL;
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if (!str)
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return 0;
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endp = strchr(str, sep);
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if (!endp) { /* act like strchrnul */
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len = strlen(str);
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endp = str + len;
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} else {
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len = endp - str;
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}
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if (endp == str)
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return 0;
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if (!next)
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return len;
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if (*endp == 0) {
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/* Don't advance past the nul. */
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*next = endp;
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} else {
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*next = endp + 1;
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}
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return len;
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}
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static int __init dm_setup_args_init(void)
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{
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dm_setup_args.minor = 0;
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dm_setup_args.ro = 0;
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dm_setup_args.target = NULL;
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dm_setup_args.target_count = 0;
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return 0;
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}
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static int __init dm_setup_cleanup(void)
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{
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struct dm_setup_target *target = dm_setup_args.target;
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struct dm_setup_target *old_target = NULL;
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while (target) {
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kfree(target->type);
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kfree(target->params);
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old_target = target;
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target = target->next;
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kfree(old_target);
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dm_setup_args.target_count--;
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}
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BUG_ON(dm_setup_args.target_count);
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return 0;
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}
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static char * __init dm_setup_parse_device_args(char *str)
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{
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char *next = NULL;
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size_t len = 0;
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/* Grab the logical name of the device to be exported to udev */
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len = get_dm_option(str, &next, DM_FIELD_SEP);
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if (!len) {
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DMERR("failed to parse device name");
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goto parse_fail;
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}
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len = min(len + 1, sizeof(dm_setup_args.name));
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strlcpy(dm_setup_args.name, str, len); /* includes nul */
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str = skip_spaces(next);
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/* Grab the UUID value or "none" */
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len = get_dm_option(str, &next, DM_FIELD_SEP);
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if (!len) {
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DMERR("failed to parse device uuid");
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goto parse_fail;
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}
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len = min(len + 1, sizeof(dm_setup_args.uuid));
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strlcpy(dm_setup_args.uuid, str, len);
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str = skip_spaces(next);
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/* Determine if the table/device will be read only or read-write */
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if (!strncmp("ro,", str, 3)) {
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dm_setup_args.ro = 1;
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} else if (!strncmp("rw,", str, 3)) {
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dm_setup_args.ro = 0;
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} else {
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DMERR("failed to parse table mode");
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goto parse_fail;
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}
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str = skip_spaces(str + 3);
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return str;
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parse_fail:
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return NULL;
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}
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static void __init dm_substitute_devices(char *str, size_t str_len)
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{
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char *candidate = str;
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char *candidate_end = str;
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char old_char;
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size_t len = 0;
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dev_t dev;
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if (str_len < 3)
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return;
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while (str && *str) {
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candidate = strchr(str, '/');
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if (!candidate)
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break;
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/* Avoid embedded slashes */
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if (candidate != str && *(candidate - 1) != DM_FIELD_SEP) {
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str = strchr(candidate, DM_FIELD_SEP);
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continue;
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}
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len = get_dm_option(candidate, &candidate_end, DM_FIELD_SEP);
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str = skip_spaces(candidate_end);
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if (len < 3 || len > 37) /* name_to_dev_t max; maj:mix min */
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continue;
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/* Temporarily terminate with a nul */
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candidate_end--;
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old_char = *candidate_end;
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*candidate_end = '\0';
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DMDEBUG("converting candidate device '%s' to dev_t", candidate);
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/* Use the boot-time specific device naming */
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dev = name_to_dev_t(candidate);
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*candidate_end = old_char;
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DMDEBUG(" -> %u", dev);
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/* No suitable replacement found */
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if (!dev)
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continue;
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/* Rewrite the /dev/path as a major:minor */
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len = snprintf(candidate, len, "%u:%u", MAJOR(dev), MINOR(dev));
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if (!len) {
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DMERR("error substituting device major/minor.");
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break;
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}
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candidate += len;
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/* Pad out with spaces (fixing our nul) */
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while (candidate < candidate_end)
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*(candidate++) = DM_FIELD_SEP;
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}
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}
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static int __init dm_setup_parse_targets(char *str)
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{
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char *next = NULL;
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size_t len = 0;
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struct dm_setup_target **target = NULL;
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/* Targets are defined as per the table format but with a
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* comma as a newline separator. */
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target = &dm_setup_args.target;
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while (str && *str) {
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*target = kzalloc(sizeof(struct dm_setup_target), GFP_KERNEL);
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if (!*target) {
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DMERR("failed to allocate memory for target %d",
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dm_setup_args.target_count);
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goto parse_fail;
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}
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dm_setup_args.target_count++;
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(*target)->begin = simple_strtoull(str, &next, 10);
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if (!next || *next != DM_FIELD_SEP) {
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DMERR("failed to parse starting sector for target %d",
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dm_setup_args.target_count - 1);
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goto parse_fail;
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}
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str = skip_spaces(next + 1);
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(*target)->length = simple_strtoull(str, &next, 10);
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if (!next || *next != DM_FIELD_SEP) {
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DMERR("failed to parse length for target %d",
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dm_setup_args.target_count - 1);
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goto parse_fail;
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}
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str = skip_spaces(next + 1);
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len = get_dm_option(str, &next, DM_FIELD_SEP);
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if (!len ||
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!((*target)->type = kstrndup(str, len, GFP_KERNEL))) {
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DMERR("failed to parse type for target %d",
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dm_setup_args.target_count - 1);
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goto parse_fail;
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}
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str = skip_spaces(next);
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len = get_dm_option(str, &next, DM_LINE_SEP);
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if (!len ||
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!((*target)->params = kstrndup(str, len, GFP_KERNEL))) {
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DMERR("failed to parse params for target %d",
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dm_setup_args.target_count - 1);
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goto parse_fail;
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}
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str = skip_spaces(next);
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/* Before moving on, walk through the copied target and
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* attempt to replace all /dev/xxx with the major:minor number.
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* It may not be possible to resolve them traditionally at
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* boot-time. */
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dm_substitute_devices((*target)->params, len);
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target = &((*target)->next);
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}
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DMDEBUG("parsed %d targets", dm_setup_args.target_count);
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return 0;
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parse_fail:
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return 1;
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}
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/*
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* Parse the command-line parameters given our kernel, but do not
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* actually try to invoke the DM device now; that is handled by
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* dm_setup_drive after the low-level disk drivers have initialised.
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* dm format is as follows:
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* dm="name uuid fmode,[table line 1],[table line 2],..."
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* May be used with root=/dev/dm-0 as it always uses the first dm minor.
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*/
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static int __init dm_setup(char *str)
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{
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dm_setup_args_init();
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str = dm_setup_parse_device_args(str);
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if (!str) {
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DMDEBUG("str is NULL");
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goto parse_fail;
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}
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/* Target parsing is delayed until we have dynamic memory */
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dm_setup_args.targets = str;
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printk(KERN_INFO "dm: will configure '%s' on dm-%d\n",
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dm_setup_args.name, dm_setup_args.minor);
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dm_early_setup = 1;
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return 1;
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parse_fail:
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printk(KERN_WARNING "dm: Invalid arguments supplied to dm=.\n");
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return 0;
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}
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static void __init dm_setup_drive(void)
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{
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struct mapped_device *md = NULL;
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struct dm_table *table = NULL;
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struct dm_setup_target *target;
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char *uuid = dm_setup_args.uuid;
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fmode_t fmode = FMODE_READ;
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/* Finish parsing the targets. */
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if (dm_setup_parse_targets(dm_setup_args.targets))
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goto parse_fail;
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if (dm_create(dm_setup_args.minor, &md)) {
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DMDEBUG("failed to create the device");
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goto dm_create_fail;
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}
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DMDEBUG("created device '%s'", dm_device_name(md));
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/* In addition to flagging the table below, the disk must be
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* set explicitly ro/rw. */
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set_disk_ro(dm_disk(md), dm_setup_args.ro);
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if (!dm_setup_args.ro)
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fmode |= FMODE_WRITE;
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if (dm_table_create(&table, fmode, dm_setup_args.target_count, md)) {
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DMDEBUG("failed to create the table");
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goto dm_table_create_fail;
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}
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target = dm_setup_args.target;
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while (target) {
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DMINFO("adding target '%llu %llu %s %s'",
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(unsigned long long) target->begin,
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(unsigned long long) target->length, target->type,
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target->params);
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if (dm_table_add_target(table, target->type, target->begin,
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target->length, target->params)) {
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DMDEBUG("failed to add the target to the table");
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goto add_target_fail;
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}
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target = target->next;
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}
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if (dm_table_complete(table)) {
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DMDEBUG("failed to complete the table");
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goto table_complete_fail;
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}
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/* Suspend the device so that we can bind it to the table. */
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if (dm_suspend(md, 0)) {
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DMDEBUG("failed to suspend the device pre-bind");
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goto suspend_fail;
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}
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/* Bind the table to the device. This is the only way to associate
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* md->map with the table and set the disk capacity directly. */
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if (dm_swap_table(md, table)) { /* should return NULL. */
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DMDEBUG("failed to bind the device to the table");
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goto table_bind_fail;
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}
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/* Finally, resume and the device should be ready. */
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if (dm_resume(md)) {
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DMDEBUG("failed to resume the device");
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goto resume_fail;
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}
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/* Export the dm device via the ioctl interface */
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if (!strcmp(DM_NO_UUID, dm_setup_args.uuid))
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uuid = NULL;
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if (dm_ioctl_export(md, dm_setup_args.name, uuid)) {
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DMDEBUG("failed to export device with given name and uuid");
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goto export_fail;
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}
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printk(KERN_INFO "dm: dm-%d is ready\n", dm_setup_args.minor);
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dm_setup_cleanup();
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return;
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export_fail:
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resume_fail:
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table_bind_fail:
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suspend_fail:
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table_complete_fail:
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add_target_fail:
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dm_table_put(table);
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dm_table_create_fail:
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dm_put(md);
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dm_create_fail:
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dm_setup_cleanup();
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parse_fail:
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printk(KERN_WARNING "dm: starting dm-%d (%s) failed\n",
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dm_setup_args.minor, dm_setup_args.name);
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}
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__setup("dm=", dm_setup);
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void __init dm_run_setup(void)
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{
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if (!dm_early_setup)
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return;
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printk(KERN_INFO "dm: attempting early device configuration.\n");
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dm_setup_drive();
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}
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