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pstore/blk: remove {un,}register_pstore_blk
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This interface is entirely unused, so remove them and various bits of
unreachable code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201016132047.3068029-4-hch@lst.de
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Christoph Hellwig authored and Kees Cook committed Dec 1, 2020
1 parent 45a8af4 commit b6f8ed3
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Showing 3 changed files with 11 additions and 119 deletions.
5 changes: 1 addition & 4 deletions Documentation/admin-guide/pstore-blk.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -151,10 +151,7 @@ otherwise KMSG_DUMP_MAX.
Configurations for driver
-------------------------

Only a block device driver cares about these configurations. A block device
driver uses ``register_pstore_blk`` to register to pstore/blk.

A non-block device driver uses ``register_pstore_device`` with
A device driver uses ``register_pstore_device`` with
``struct pstore_device_info`` to register to pstore/blk.

.. kernel-doc:: fs/pstore/blk.c
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83 changes: 10 additions & 73 deletions fs/pstore/blk.c
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Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,6 @@ MODULE_PARM_DESC(blkdev, "block device for pstore storage");
static DEFINE_MUTEX(pstore_blk_lock);
static struct block_device *psblk_bdev;
static struct pstore_zone_info *pstore_zone_info;
static pstore_blk_panic_write_op blkdev_panic_write;

struct bdev_info {
dev_t devt;
Expand Down Expand Up @@ -341,24 +340,11 @@ static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
return ret;
}

static ssize_t psblk_blk_panic_write(const char *buf, size_t size,
loff_t off)
{
int ret;

if (!blkdev_panic_write)
return -EOPNOTSUPP;

/* size and off must align to SECTOR_SIZE for block device */
ret = blkdev_panic_write(buf, off >> SECTOR_SHIFT,
size >> SECTOR_SHIFT);
/* try next zone */
if (ret == -ENOMSG)
return ret;
return ret ? -EIO : size;
}

static int __register_pstore_blk(struct pstore_blk_info *info)
/*
* This takes its configuration only from the module parameters now.
* See psblk_get_bdev() and blkdev.
*/
static int __register_pstore_blk(void)
{
char bdev_name[BDEVNAME_SIZE];
struct block_device *bdev;
Expand All @@ -378,68 +364,34 @@ static int __register_pstore_blk(struct pstore_blk_info *info)
}

/* only allow driver matching the @blkdev */
if (!binfo.devt || (!best_effort &&
MAJOR(binfo.devt) != info->major)) {
pr_debug("invalid major %u (expect %u)\n",
info->major, MAJOR(binfo.devt));
if (!binfo.devt) {
pr_debug("no major\n");
ret = -ENODEV;
goto err_put_bdev;
}

/* psblk_bdev must be assigned before register to pstore/blk */
psblk_bdev = bdev;
blkdev_panic_write = info->panic_write;

/* Copy back block device details. */
info->devt = binfo.devt;
info->nr_sects = binfo.nr_sects;
info->start_sect = binfo.start_sect;

memset(&dev, 0, sizeof(dev));
dev.total_size = info->nr_sects << SECTOR_SHIFT;
dev.flags = info->flags;
dev.total_size = binfo.nr_sects << SECTOR_SHIFT;
dev.read = psblk_generic_blk_read;
dev.write = psblk_generic_blk_write;
dev.erase = NULL;
dev.panic_write = info->panic_write ? psblk_blk_panic_write : NULL;

ret = __register_pstore_device(&dev);
if (ret)
goto err_put_bdev;

bdevname(bdev, bdev_name);
pr_info("attached %s%s\n", bdev_name,
info->panic_write ? "" : " (no dedicated panic_write!)");
pr_info("attached %s (no dedicated panic_write!)\n", bdev_name);
return 0;

err_put_bdev:
psblk_bdev = NULL;
blkdev_panic_write = NULL;
psblk_put_bdev(bdev, holder);
return ret;
}

/**
* register_pstore_blk() - register block device to pstore/blk
*
* @info: details on the desired block device interface
*
* Return:
* * 0 - OK
* * Others - something error.
*/
int register_pstore_blk(struct pstore_blk_info *info)
{
int ret;

mutex_lock(&pstore_blk_lock);
ret = __register_pstore_blk(info);
mutex_unlock(&pstore_blk_lock);

return ret;
}
EXPORT_SYMBOL_GPL(register_pstore_blk);

static void __unregister_pstore_blk(unsigned int major)
{
struct pstore_device_info dev = { .read = psblk_generic_blk_read };
Expand All @@ -449,24 +401,10 @@ static void __unregister_pstore_blk(unsigned int major)
if (psblk_bdev && MAJOR(psblk_bdev->bd_dev) == major) {
__unregister_pstore_device(&dev);
psblk_put_bdev(psblk_bdev, holder);
blkdev_panic_write = NULL;
psblk_bdev = NULL;
}
}

/**
* unregister_pstore_blk() - unregister block device from pstore/blk
*
* @major: the major device number of device
*/
void unregister_pstore_blk(unsigned int major)
{
mutex_lock(&pstore_blk_lock);
__unregister_pstore_blk(major);
mutex_unlock(&pstore_blk_lock);
}
EXPORT_SYMBOL_GPL(unregister_pstore_blk);

/* get information of pstore/blk */
int pstore_blk_get_config(struct pstore_blk_config *info)
{
Expand All @@ -483,12 +421,11 @@ EXPORT_SYMBOL_GPL(pstore_blk_get_config);

static int __init pstore_blk_init(void)
{
struct pstore_blk_info info = { };
int ret = 0;

mutex_lock(&pstore_blk_lock);
if (!pstore_zone_info && best_effort && blkdev[0])
ret = __register_pstore_blk(&info);
ret = __register_pstore_blk();
mutex_unlock(&pstore_blk_lock);

return ret;
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42 changes: 0 additions & 42 deletions include/linux/pstore_blk.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,48 +7,6 @@
#include <linux/pstore.h>
#include <linux/pstore_zone.h>

/**
* typedef pstore_blk_panic_write_op - panic write operation to block device
*
* @buf: the data to write
* @start_sect: start sector to block device
* @sects: sectors count on buf
*
* Return: On success, zero should be returned. Others excluding -ENOMSG
* mean error. -ENOMSG means to try next zone.
*
* Panic write to block device must be aligned to SECTOR_SIZE.
*/
typedef int (*pstore_blk_panic_write_op)(const char *buf, sector_t start_sect,
sector_t sects);

/**
* struct pstore_blk_info - pstore/blk registration details
*
* @major: Which major device number to support with pstore/blk
* @flags: The supported PSTORE_FLAGS_* from linux/pstore.h.
* @panic_write:The write operation only used for the panic case.
* This can be NULL, but is recommended to avoid losing
* crash data if the kernel's IO path or work queues are
* broken during a panic.
* @devt: The dev_t that pstore/blk has attached to.
* @nr_sects: Number of sectors on @devt.
* @start_sect: Starting sector on @devt.
*/
struct pstore_blk_info {
unsigned int major;
unsigned int flags;
pstore_blk_panic_write_op panic_write;

/* Filled in by pstore/blk after registration. */
dev_t devt;
sector_t nr_sects;
sector_t start_sect;
};

int register_pstore_blk(struct pstore_blk_info *info);
void unregister_pstore_blk(unsigned int major);

/**
* struct pstore_device_info - back-end pstore/blk driver structure.
*
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