[PATCH 3/9] pstore/blk: remove {un,}register_pstore_blk

From: Christoph Hellwig
Date: Fri Oct 16 2020 - 09:29:43 EST


This interface is entirely unused, so remove them and various bits of
unreachable code.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
Documentation/admin-guide/pstore-blk.rst | 8 +--
fs/pstore/blk.c | 79 ++----------------------
include/linux/pstore_blk.h | 42 -------------
3 files changed, 7 insertions(+), 122 deletions(-)

diff --git a/Documentation/admin-guide/pstore-blk.rst b/Documentation/admin-guide/pstore-blk.rst
index d9ec8b0572d3b2..84477621384d85 100644
--- a/Documentation/admin-guide/pstore-blk.rst
+++ b/Documentation/admin-guide/pstore-blk.rst
@@ -151,13 +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.
-
-.. kernel-doc:: fs/pstore/blk.c
- :identifiers: register_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
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index fcd5563dde063c..7f8368e94b3604 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -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;
@@ -341,24 +340,7 @@ 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)
+static int __register_pstore_blk(void)
{
char bdev_name[BDEVNAME_SIZE];
struct block_device *bdev;
@@ -378,68 +360,34 @@ 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 };
@@ -449,24 +397,10 @@ 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)
{
@@ -483,12 +417,11 @@ 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;
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
index 61e914522b0193..99564f93d77488 100644
--- a/include/linux/pstore_blk.h
+++ b/include/linux/pstore_blk.h
@@ -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.
*
--
2.28.0