Stop poking into block layer internals and just open the block device
file an use kernel_read and kernel_write on it. Note that this means
the transformation from name_to_dev_t can't be used anymore when
pstore_blk is loaded as a module: a full filesystem device path name
must be used instead. Additionally removes ":internal:" kerndoc link,
since no such documentation remains.
Co-developed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
Documentation/admin-guide/pstore-blk.rst | 3 -
fs/pstore/blk.c | 264 +++++++----------------
2 files changed, 83 insertions(+), 184 deletions(-)
diff --git a/Documentation/admin-guide/pstore-blk.rst b/Documentation/admin-guide/pstore-blk.rst
index 49d8149f8d32..79f6d23e8cda 100644
--- a/Documentation/admin-guide/pstore-blk.rst
+++ b/Documentation/admin-guide/pstore-blk.rst
@@ -227,8 +227,5 @@ 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:
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 7d8e5a1ddd5b..dc5ff763d414 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -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);
@@ -60,23 +61,25 @@ MODULE_PARM_DESC(best_effort, "use best effort to write (i.e. do not require sto
*
* 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
+ * blkdev accepts the following variants, when built as a module:
+ * 1) /dev/<disk_name> represents the device number of disk
+ * 2) /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
+ * 3) /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
+ *
+ * blkdev accepts the following variants when built into the kernel:
+ * 1) <hex_major><hex_minor> device number in hexadecimal representation,
+ * with no leading 0x, for example b302.
+ * 2) 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
+ * 3) 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
+ * 4) <major>:<minor> major and minor number of the device separated by
* a colon.
*/
static char blkdev[80] = CONFIG_PSTORE_BLK_BLKDEV;
@@ -88,15 +91,9 @@ 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 file *psblk_file;
static struct pstore_zone_info *pstore_zone_info;
-struct bdev_info {
- dev_t devt;
- sector_t nr_sects;
- sector_t start_sect;
-};
-
#define check_size(name, alignsize) ({ \
long _##name_ = (name); \
_##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \
@@ -219,203 +216,73 @@ 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(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 pstore_device_info dev = {
+ .read = psblk_generic_blk_read,
+ .write = psblk_generic_blk_write,
+ };
+ 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;
-
- 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;
+ inode = I_BDEV(psblk_file->f_mapping->host)->bd_inode;
+ dev.total_size = i_size_read(inode);
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)
+static void __unregister_pstore_blk(struct file *device)
{
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) {
+ if (psblk_file && psblk_file == device) {
__unregister_pstore_device(&dev);
- psblk_put_bdev(psblk_bdev, holder);
- psblk_bdev = NULL;
+ fput(psblk_file);
+ psblk_file = NULL;
}
}
@@ -433,13 +300,48 @@ 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 pstore_blk_init(void)
{
int ret = 0;
mutex_lock(&pstore_blk_lock);
- if (!pstore_zone_info && best_effort && blkdev[0])
- ret = __register_pstore_blk();
+ if (!pstore_zone_info && best_effort && blkdev[0]) {
+ ret = __register_pstore_blk(early_boot_devpath(blkdev));
+ if (ret == 0 && pstore_zone_info)
+ pr_info("attached %s:%s (%zu) (no dedicated panic_write!)\n",
+ pstore_zone_info->name, blkdev,
+ pstore_zone_info->total_size);
+ }
mutex_unlock(&pstore_blk_lock);
return ret;
@@ -449,8 +351,8 @@ 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));
+ if (psblk_file)
+ __unregister_pstore_blk(psblk_file);
else {
struct pstore_device_info dev = { };
--
2.25.1
