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pstore updates for v5.14-rc1

Browse Source 
Use normal block device I/O path for pstore/blk. (Christoph Hellwig,
 Kees Cook, Pu Lehui)
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Merge tag 'pstore-v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:
 "Use normal block device I/O path for pstore/blk. (Christoph Hellwig,
  Kees Cook, Pu Lehui)"

* tag 'pstore-v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/blk: Include zone in pstore_device_info
  pstore/blk: Fix kerndoc and redundancy on blkdev param
  pstore/blk: Use the normal block device I/O path
  pstore/blk: Move verify_size() macro out of function
  pstore/blk: Improve failure reporting
This commit is contained in:
Linus Torvalds 2021-06-28 19:57:00 -07:00
commit 07bdc0746a
4 changed files with 169 additions and 281 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
Documentation/admin-guide/pstore-blk.rst
View File

@ -45,15 +45,18 @@ blkdev
The block device to use. Most of the time, it is a partition of block device.
It's required for pstore/blk. It is also used for MTD device.
It accepts the following variants for block device:
When pstore/blk is built as a module, "blkdev" accepts the following variants:
1. <hex_major><hex_minor> device number in hexadecimal represents itself; no
leading 0x, for example b302.
#. /dev/<disk_name> represents the device number of disk
1. /dev/<disk_name> represents the device number of disk
#. /dev/<disk_name><decimal> represents the device number of partition - device
number of disk plus the partition number
#. /dev/<disk_name>p<decimal> - same as the above; this form is used when disk
name of partitioned disk ends with a digit.
When pstore/blk is built into the kernel, "blkdev" accepts the following variants:
#. <hex_major><hex_minor> device number in hexadecimal representation,
with no leading 0x, for example b302.
#. PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF represents 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,
@ -227,8 +230,5 @@ For developer reference, here are all the important structures and APIs:
.. kernel-doc:: include/linux/pstore_zone.h
:internal:
.. kernel-doc:: fs/pstore/blk.c
:internal:
.. kernel-doc:: include/linux/pstore_blk.h
:internal:

10
drivers/mtd/mtdpstore.c
View File

@ -423,13 +423,13 @@ static void mtdpstore_notify_add(struct mtd_info *mtd)
longcnt = BITS_TO_LONGS(div_u64(mtd->size, mtd->erasesize));
cxt->badmap = kcalloc(longcnt, sizeof(long), GFP_KERNEL);
cxt->dev.total_size = mtd->size;
/* just support dmesg right now */
cxt->dev.flags = PSTORE_FLAGS_DMESG;
cxt->dev.read = mtdpstore_read;
cxt->dev.write = mtdpstore_write;
cxt->dev.erase = mtdpstore_erase;
cxt->dev.panic_write = mtdpstore_panic_write;
cxt->dev.zone.read = mtdpstore_read;
cxt->dev.zone.write = mtdpstore_write;
cxt->dev.zone.erase = mtdpstore_erase;
cxt->dev.zone.panic_write = mtdpstore_panic_write;
cxt->dev.zone.total_size = mtd->size;
ret = register_pstore_device(&cxt->dev);
if (ret) {

399
fs/pstore/blk.c
View File

@ -8,15 +8,16 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include "../../block/blk.h"
#include <linux/blkdev.h>
#include <linux/string.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/pstore_blk.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/init_syscalls.h>
#include <linux/mount.h>
#include <linux/uio.h>
static long kmsg_size = CONFIG_PSTORE_BLK_KMSG_SIZE;
module_param(kmsg_size, long, 0400);
@ -57,27 +58,7 @@ MODULE_PARM_DESC(best_effort, "use best effort to write (i.e. do not require sto
/*
* blkdev - the block device to use for pstore storage
*
* Usually, this will be a partition of a block device.
*
* blkdev accepts the following variants:
* 1) <hex_major><hex_minor> device number in hexadecimal representation,
* with no leading 0x, for example b302.
* 2) /dev/<disk_name> represents the device number of disk
* 3) /dev/<disk_name><decimal> represents the device number
* of partition - device number of disk plus the partition number
* 4) /dev/<disk_name>p<decimal> - same as the above, that form is
* used when disk name of partitioned disk ends on a digit.
* 5) 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.
* 6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
* a partition with a known unique id.
* 7) <major>:<minor> major and minor number of the device separated by
* a colon.
* See Documentation/admin-guide/pstore-blk.rst for details.
*/
static char blkdev[80] = CONFIG_PSTORE_BLK_BLKDEV;
module_param_string(blkdev, blkdev, 80, 0400);
@ -88,14 +69,8 @@ MODULE_PARM_DESC(blkdev, "block device for pstore storage");
* during the register/unregister functions.
*/
static DEFINE_MUTEX(pstore_blk_lock);
static struct block_device *psblk_bdev;
static struct pstore_zone_info *pstore_zone_info;
struct bdev_info {
dev_t devt;
sector_t nr_sects;
sector_t start_sect;
};
static struct file *psblk_file;
static struct pstore_device_info *pstore_device_info;
#define check_size(name, alignsize) ({ \
long _##name_ = (name); \
@ -108,57 +83,63 @@ struct bdev_info {
_##name_; \
})
#define verify_size(name, alignsize, enabled) { \
long _##name_; \
if (enabled) \
_##name_ = check_size(name, alignsize); \
else \
_##name_ = 0; \
/* Synchronize module parameters with resuls. */ \
name = _##name_ / 1024; \
dev->zone.name = _##name_; \
}
static int __register_pstore_device(struct pstore_device_info *dev)
{
int ret;
lockdep_assert_held(&pstore_blk_lock);
if (!dev || !dev->total_size || !dev->read || !dev->write)
if (!dev) {
pr_err("NULL device info\n");
return -EINVAL;
}
if (!dev->zone.total_size) {
pr_err("zero sized device\n");
return -EINVAL;
}
if (!dev->zone.read) {
pr_err("no read handler for device\n");
return -EINVAL;
}
if (!dev->zone.write) {
pr_err("no write handler for device\n");
return -EINVAL;
}
/* someone already registered before */
if (pstore_zone_info)
if (pstore_device_info)
return -EBUSY;
pstore_zone_info = kzalloc(sizeof(struct pstore_zone_info), GFP_KERNEL);
if (!pstore_zone_info)
return -ENOMEM;
/* zero means not limit on which backends to attempt to store. */
if (!dev->flags)
dev->flags = UINT_MAX;
#define verify_size(name, alignsize, enabled) { \
long _##name_; \
if (enabled) \
_##name_ = check_size(name, alignsize); \
else \
_##name_ = 0; \
name = _##name_ / 1024; \
pstore_zone_info->name = _##name_; \
}
/* Copy in module parameters. */
verify_size(kmsg_size, 4096, dev->flags & PSTORE_FLAGS_DMESG);
verify_size(pmsg_size, 4096, dev->flags & PSTORE_FLAGS_PMSG);
verify_size(console_size, 4096, dev->flags & PSTORE_FLAGS_CONSOLE);
verify_size(ftrace_size, 4096, dev->flags & PSTORE_FLAGS_FTRACE);
#undef verify_size
dev->zone.max_reason = max_reason;
pstore_zone_info->total_size = dev->total_size;
pstore_zone_info->max_reason = max_reason;
pstore_zone_info->read = dev->read;
pstore_zone_info->write = dev->write;
pstore_zone_info->erase = dev->erase;
pstore_zone_info->panic_write = dev->panic_write;
pstore_zone_info->name = KBUILD_MODNAME;
pstore_zone_info->owner = THIS_MODULE;
/* Initialize required zone ownership details. */
dev->zone.name = KBUILD_MODNAME;
dev->zone.owner = THIS_MODULE;
ret = register_pstore_zone(&dev->zone);
if (ret == 0)
pstore_device_info = dev;
ret = register_pstore_zone(pstore_zone_info);
if (ret) {
kfree(pstore_zone_info);
pstore_zone_info = NULL;
}
return ret;
}
/**
@ -185,10 +166,9 @@ EXPORT_SYMBOL_GPL(register_pstore_device);
static void __unregister_pstore_device(struct pstore_device_info *dev)
{
lockdep_assert_held(&pstore_blk_lock);
if (pstore_zone_info && pstore_zone_info->read == dev->read) {
unregister_pstore_zone(pstore_zone_info);
kfree(pstore_zone_info);
pstore_zone_info = NULL;
if (pstore_device_info && pstore_device_info == dev) {
unregister_pstore_zone(&dev->zone);
pstore_device_info = NULL;
}
}
@ -205,206 +185,61 @@ void unregister_pstore_device(struct pstore_device_info *dev)
}
EXPORT_SYMBOL_GPL(unregister_pstore_device);
/**
* psblk_get_bdev() - open block device
*
* @holder: Exclusive holder identifier
* @info: Information about bdev to fill in
*
* Return: pointer to block device on success and others on error.
*
* On success, the returned block_device has reference count of one.
*/
static struct block_device *psblk_get_bdev(void *holder,
struct bdev_info *info)
{
struct block_device *bdev = ERR_PTR(-ENODEV);
fmode_t mode = FMODE_READ | FMODE_WRITE;
sector_t nr_sects;
lockdep_assert_held(&pstore_blk_lock);
if (pstore_zone_info)
return ERR_PTR(-EBUSY);
if (!blkdev[0])
return ERR_PTR(-ENODEV);
if (holder)
mode |= FMODE_EXCL;
bdev = blkdev_get_by_path(blkdev, mode, holder);
if (IS_ERR(bdev)) {
dev_t devt;
devt = name_to_dev_t(blkdev);
if (devt == 0)
return ERR_PTR(-ENODEV);
bdev = blkdev_get_by_dev(devt, mode, holder);
if (IS_ERR(bdev))
return bdev;
}
nr_sects = bdev_nr_sectors(bdev);
if (!nr_sects) {
pr_err("not enough space for '%s'\n", blkdev);
blkdev_put(bdev, mode);
return ERR_PTR(-ENOSPC);
}
if (info) {
info->devt = bdev->bd_dev;
info->nr_sects = nr_sects;
info->start_sect = get_start_sect(bdev);
}
return bdev;
}
static void psblk_put_bdev(struct block_device *bdev, void *holder)
{
fmode_t mode = FMODE_READ | FMODE_WRITE;
lockdep_assert_held(&pstore_blk_lock);
if (!bdev)
return;
if (holder)
mode |= FMODE_EXCL;
blkdev_put(bdev, mode);
}
static ssize_t psblk_generic_blk_read(char *buf, size_t bytes, loff_t pos)
{
struct block_device *bdev = psblk_bdev;
struct file file;
struct kiocb kiocb;
struct iov_iter iter;
struct kvec iov = {.iov_base = buf, .iov_len = bytes};
if (!bdev)
return -ENODEV;
memset(&file, 0, sizeof(struct file));
file.f_mapping = bdev->bd_inode->i_mapping;
file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
file.f_inode = bdev->bd_inode;
file_ra_state_init(&file.f_ra, file.f_mapping);
init_sync_kiocb(&kiocb, &file);
kiocb.ki_pos = pos;
iov_iter_kvec(&iter, READ, &iov, 1, bytes);
return generic_file_read_iter(&kiocb, &iter);
return kernel_read(psblk_file, buf, bytes, &pos);
}
static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
loff_t pos)
{
struct block_device *bdev = psblk_bdev;
struct iov_iter iter;
struct kiocb kiocb;
struct file file;
ssize_t ret;
struct kvec iov = {.iov_base = (void *)buf, .iov_len = bytes};
if (!bdev)
return -ENODEV;
/* Console/Ftrace backend may handle buffer until flush dirty zones */
if (in_interrupt() || irqs_disabled())
return -EBUSY;
memset(&file, 0, sizeof(struct file));
file.f_mapping = bdev->bd_inode->i_mapping;
file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
file.f_inode = bdev->bd_inode;
init_sync_kiocb(&kiocb, &file);
kiocb.ki_pos = pos;
iov_iter_kvec(&iter, WRITE, &iov, 1, bytes);
inode_lock(bdev->bd_inode);
ret = generic_write_checks(&kiocb, &iter);
if (ret > 0)
ret = generic_perform_write(&file, &iter, pos);
inode_unlock(bdev->bd_inode);
if (likely(ret > 0)) {
const struct file_operations f_op = {.fsync = blkdev_fsync};
file.f_op = &f_op;
kiocb.ki_pos += ret;
ret = generic_write_sync(&kiocb, ret);
}
return ret;
return kernel_write(psblk_file, buf, bytes, &pos);
}
/*
* This takes its configuration only from the module parameters now.
* See psblk_get_bdev() and blkdev.
*/
static int __register_pstore_blk(void)
static int __register_pstore_blk(struct pstore_device_info *dev,
const char *devpath)
{
char bdev_name[BDEVNAME_SIZE];
struct block_device *bdev;
struct pstore_device_info dev;
struct bdev_info binfo;
void *holder = blkdev;
struct inode *inode;
int ret = -ENODEV;
lockdep_assert_held(&pstore_blk_lock);
/* hold bdev exclusively */
memset(&binfo, 0, sizeof(binfo));
bdev = psblk_get_bdev(holder, &binfo);
if (IS_ERR(bdev)) {
pr_err("failed to open '%s'!\n", blkdev);
return PTR_ERR(bdev);
psblk_file = filp_open(devpath, O_RDWR | O_DSYNC | O_NOATIME | O_EXCL, 0);
if (IS_ERR(psblk_file)) {
ret = PTR_ERR(psblk_file);
pr_err("failed to open '%s': %d!\n", devpath, ret);
goto err;
}
/* only allow driver matching the @blkdev */
if (!binfo.devt) {
pr_debug("no major\n");
ret = -ENODEV;
goto err_put_bdev;
inode = file_inode(psblk_file);
if (!S_ISBLK(inode->i_mode)) {
pr_err("'%s' is not block device!\n", devpath);
goto err_fput;
}
/* psblk_bdev must be assigned before register to pstore/blk */
psblk_bdev = bdev;
inode = I_BDEV(psblk_file->f_mapping->host)->bd_inode;
dev->zone.total_size = i_size_read(inode);
memset(&dev, 0, sizeof(dev));
dev.total_size = binfo.nr_sects << SECTOR_SHIFT;
dev.read = psblk_generic_blk_read;
dev.write = psblk_generic_blk_write;
ret = __register_pstore_device(&dev);
ret = __register_pstore_device(dev);
if (ret)
goto err_put_bdev;
goto err_fput;
bdevname(bdev, bdev_name);
pr_info("attached %s (no dedicated panic_write!)\n", bdev_name);
return 0;
err_put_bdev:
psblk_bdev = NULL;
psblk_put_bdev(bdev, holder);
err_fput:
fput(psblk_file);
err:
psblk_file = NULL;
return ret;
}
static void __unregister_pstore_blk(unsigned int major)
{
struct pstore_device_info dev = { .read = psblk_generic_blk_read };
void *holder = blkdev;
lockdep_assert_held(&pstore_blk_lock);
if (psblk_bdev && MAJOR(psblk_bdev->bd_dev) == major) {
__unregister_pstore_device(&dev);
psblk_put_bdev(psblk_bdev, holder);
psblk_bdev = NULL;
}
}
/* get information of pstore/blk */
int pstore_blk_get_config(struct pstore_blk_config *info)
{
@ -419,13 +254,93 @@ int pstore_blk_get_config(struct pstore_blk_config *info)
}
EXPORT_SYMBOL_GPL(pstore_blk_get_config);
#ifndef MODULE
static const char devname[] = "/dev/pstore-blk";
static __init const char *early_boot_devpath(const char *initial_devname)
{
/*
* During early boot the real root file system hasn't been
* mounted yet, and no device nodes are present yet. Use the
* same scheme to find the device that we use for mounting
* the root file system.
*/
dev_t dev = name_to_dev_t(initial_devname);
if (!dev) {
pr_err("failed to resolve '%s'!\n", initial_devname);
return initial_devname;
}
init_unlink(devname);
init_mknod(devname, S_IFBLK | 0600, new_encode_dev(dev));
return devname;
}
#else
static inline const char *early_boot_devpath(const char *initial_devname)
{
return initial_devname;
}
#endif
static int __init __best_effort_init(void)
{
struct pstore_device_info *best_effort_dev;
int ret;
/* No best-effort mode requested. */
if (!best_effort)
return 0;
/* Reject an empty blkdev. */
if (!blkdev[0]) {
pr_err("blkdev empty with best_effort=Y\n");
return -EINVAL;
}
best_effort_dev = kzalloc(sizeof(*best_effort_dev), GFP_KERNEL);
if (!best_effort_dev)
return -ENOMEM;
best_effort_dev->zone.read = psblk_generic_blk_read;
best_effort_dev->zone.write = psblk_generic_blk_write;
ret = __register_pstore_blk(best_effort_dev,
early_boot_devpath(blkdev));
if (ret)
kfree(best_effort_dev);
else
pr_info("attached %s (%zu) (no dedicated panic_write!)\n",
blkdev, best_effort_dev->zone.total_size);
return ret;
}
static void __exit __best_effort_exit(void)
{
/*
* Currently, the only user of psblk_file is best_effort, so
* we can assume that pstore_device_info is associated with it.
* Once there are "real" blk devices, there will need to be a
* dedicated pstore_blk_info, etc.
*/
if (psblk_file) {
struct pstore_device_info *dev = pstore_device_info;
__unregister_pstore_device(dev);
kfree(dev);
fput(psblk_file);
psblk_file = NULL;
}
}
static int __init pstore_blk_init(void)
{
int ret = 0;
int ret;
mutex_lock(&pstore_blk_lock);
if (!pstore_zone_info && best_effort && blkdev[0])
ret = __register_pstore_blk();
ret = __best_effort_init();
mutex_unlock(&pstore_blk_lock);
return ret;
@ -435,15 +350,9 @@ late_initcall(pstore_blk_init);
static void __exit pstore_blk_exit(void)
{
mutex_lock(&pstore_blk_lock);
if (psblk_bdev)
__unregister_pstore_blk(MAJOR(psblk_bdev->bd_dev));
else {
struct pstore_device_info dev = { };
if (pstore_zone_info)
dev.read = pstore_zone_info->read;
__unregister_pstore_device(&dev);
}
__best_effort_exit();
/* If we've been asked to unload, unregister any remaining device. */
__unregister_pstore_device(pstore_device_info);
mutex_unlock(&pstore_blk_lock);
}
module_exit(pstore_blk_exit);

27
include/linux/pstore_blk.h
View File

@ -10,36 +10,15 @@
/**
* struct pstore_device_info - back-end pstore/blk driver structure.
*
* @total_size: The total size in bytes pstore/blk can use. It must be greater
* than 4096 and be multiple of 4096.
* @flags: Refer to macro starting with PSTORE_FLAGS defined in
* linux/pstore.h. It means what front-ends this device support.
* Zero means all backends for compatible.
* @read: The general read operation. Both of the function parameters
* @size and @offset are relative value to bock device (not the
* whole disk).
* On success, the number of bytes should be returned, others
* means error.
* @write: The same as @read, but the following error number:
* -EBUSY means try to write again later.
* -ENOMSG means to try next zone.
* @erase: The general erase operation for device with special removing
* job. Both of the function parameters @size and @offset are
* relative value to storage.
* Return 0 on success and others on failure.
* @panic_write:The write operation only used for panic case. It's optional
* if you do not care panic log. The parameters are relative
* value to storage.
* On success, the number of bytes should be returned, others
* excluding -ENOMSG mean error. -ENOMSG means to try next zone.
* @zone: The struct pstore_zone_info details.
*
*/
struct pstore_device_info {
unsigned long total_size;
unsigned int flags;
pstore_zone_read_op read;
pstore_zone_write_op write;
pstore_zone_erase_op erase;
pstore_zone_write_op panic_write;
struct pstore_zone_info zone;
};
int register_pstore_device(struct pstore_device_info *dev);