mirror of https://gitee.com/openkylin/linux.git
pstore/blk: Use the normal block device I/O path
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@lst.de> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook
parent
2a03ddbde1
commit
7bb9557b48
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@ -227,8 +227,5 @@ For developer reference, here are all the important structures and APIs:
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.. kernel-doc:: include/linux/pstore_zone.h
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:internal:
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.. kernel-doc:: fs/pstore/blk.c
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:internal:
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.. kernel-doc:: include/linux/pstore_blk.h
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:internal:
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264
fs/pstore/blk.c
264
fs/pstore/blk.c
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@ -8,15 +8,16 @@
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include "../../block/blk.h"
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#include <linux/blkdev.h>
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#include <linux/string.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/platform_device.h>
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#include <linux/pstore_blk.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/init_syscalls.h>
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#include <linux/mount.h>
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#include <linux/uio.h>
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static long kmsg_size = CONFIG_PSTORE_BLK_KMSG_SIZE;
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module_param(kmsg_size, long, 0400);
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@ -60,23 +61,25 @@ MODULE_PARM_DESC(best_effort, "use best effort to write (i.e. do not require sto
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*
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* Usually, this will be a partition of a block device.
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*
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* blkdev accepts the following variants:
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* blkdev accepts the following variants, when built as a module:
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* 1) /dev/<disk_name> represents the device number of disk
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* 2) /dev/<disk_name><decimal> represents the device number
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* of partition - device number of disk plus the partition number
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* 3) /dev/<disk_name>p<decimal> - same as the above, that form is
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* used when disk name of partitioned disk ends on a digit.
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*
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* blkdev accepts the following variants when built into the kernel:
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* 1) <hex_major><hex_minor> device number in hexadecimal representation,
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* with no leading 0x, for example b302.
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* 2) /dev/<disk_name> represents the device number of disk
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* 3) /dev/<disk_name><decimal> represents the device number
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* of partition - device number of disk plus the partition number
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* 4) /dev/<disk_name>p<decimal> - same as the above, that form is
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* used when disk name of partitioned disk ends on a digit.
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* 5) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
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* 2) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
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* unique id of a partition if the partition table provides it.
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* The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
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* partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
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* filled hex representation of the 32-bit "NT disk signature", and PP
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* is a zero-filled hex representation of the 1-based partition number.
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* 6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
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* 3) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
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* a partition with a known unique id.
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* 7) <major>:<minor> major and minor number of the device separated by
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* 4) <major>:<minor> major and minor number of the device separated by
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* a colon.
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*/
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static char blkdev[80] = CONFIG_PSTORE_BLK_BLKDEV;
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@ -88,15 +91,9 @@ MODULE_PARM_DESC(blkdev, "block device for pstore storage");
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* during the register/unregister functions.
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*/
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static DEFINE_MUTEX(pstore_blk_lock);
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static struct block_device *psblk_bdev;
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static struct file *psblk_file;
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static struct pstore_zone_info *pstore_zone_info;
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struct bdev_info {
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dev_t devt;
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sector_t nr_sects;
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sector_t start_sect;
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};
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#define check_size(name, alignsize) ({ \
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long _##name_ = (name); \
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_##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \
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@ -219,203 +216,73 @@ void unregister_pstore_device(struct pstore_device_info *dev)
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}
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EXPORT_SYMBOL_GPL(unregister_pstore_device);
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/**
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* psblk_get_bdev() - open block device
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*
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* @holder: Exclusive holder identifier
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* @info: Information about bdev to fill in
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*
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* Return: pointer to block device on success and others on error.
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*
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* On success, the returned block_device has reference count of one.
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*/
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static struct block_device *psblk_get_bdev(void *holder,
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struct bdev_info *info)
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{
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struct block_device *bdev = ERR_PTR(-ENODEV);
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fmode_t mode = FMODE_READ | FMODE_WRITE;
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sector_t nr_sects;
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lockdep_assert_held(&pstore_blk_lock);
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if (pstore_zone_info)
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return ERR_PTR(-EBUSY);
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if (!blkdev[0])
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return ERR_PTR(-ENODEV);
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if (holder)
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mode |= FMODE_EXCL;
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bdev = blkdev_get_by_path(blkdev, mode, holder);
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if (IS_ERR(bdev)) {
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dev_t devt;
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devt = name_to_dev_t(blkdev);
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if (devt == 0)
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return ERR_PTR(-ENODEV);
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bdev = blkdev_get_by_dev(devt, mode, holder);
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if (IS_ERR(bdev))
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return bdev;
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}
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nr_sects = bdev_nr_sectors(bdev);
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if (!nr_sects) {
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pr_err("not enough space for '%s'\n", blkdev);
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blkdev_put(bdev, mode);
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return ERR_PTR(-ENOSPC);
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}
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if (info) {
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info->devt = bdev->bd_dev;
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info->nr_sects = nr_sects;
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info->start_sect = get_start_sect(bdev);
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}
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return bdev;
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}
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static void psblk_put_bdev(struct block_device *bdev, void *holder)
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{
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fmode_t mode = FMODE_READ | FMODE_WRITE;
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lockdep_assert_held(&pstore_blk_lock);
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if (!bdev)
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return;
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if (holder)
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mode |= FMODE_EXCL;
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blkdev_put(bdev, mode);
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}
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static ssize_t psblk_generic_blk_read(char *buf, size_t bytes, loff_t pos)
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{
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struct block_device *bdev = psblk_bdev;
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struct file file;
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struct kiocb kiocb;
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struct iov_iter iter;
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struct kvec iov = {.iov_base = buf, .iov_len = bytes};
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if (!bdev)
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return -ENODEV;
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memset(&file, 0, sizeof(struct file));
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file.f_mapping = bdev->bd_inode->i_mapping;
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file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
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file.f_inode = bdev->bd_inode;
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file_ra_state_init(&file.f_ra, file.f_mapping);
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init_sync_kiocb(&kiocb, &file);
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kiocb.ki_pos = pos;
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iov_iter_kvec(&iter, READ, &iov, 1, bytes);
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return generic_file_read_iter(&kiocb, &iter);
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return kernel_read(psblk_file, buf, bytes, &pos);
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}
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static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
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loff_t pos)
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{
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struct block_device *bdev = psblk_bdev;
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struct iov_iter iter;
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struct kiocb kiocb;
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struct file file;
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ssize_t ret;
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struct kvec iov = {.iov_base = (void *)buf, .iov_len = bytes};
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if (!bdev)
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return -ENODEV;
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/* Console/Ftrace backend may handle buffer until flush dirty zones */
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if (in_interrupt() || irqs_disabled())
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return -EBUSY;
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memset(&file, 0, sizeof(struct file));
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file.f_mapping = bdev->bd_inode->i_mapping;
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file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
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file.f_inode = bdev->bd_inode;
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init_sync_kiocb(&kiocb, &file);
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kiocb.ki_pos = pos;
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iov_iter_kvec(&iter, WRITE, &iov, 1, bytes);
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inode_lock(bdev->bd_inode);
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ret = generic_write_checks(&kiocb, &iter);
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if (ret > 0)
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ret = generic_perform_write(&file, &iter, pos);
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inode_unlock(bdev->bd_inode);
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if (likely(ret > 0)) {
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const struct file_operations f_op = {.fsync = blkdev_fsync};
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file.f_op = &f_op;
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kiocb.ki_pos += ret;
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ret = generic_write_sync(&kiocb, ret);
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}
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return ret;
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return kernel_write(psblk_file, buf, bytes, &pos);
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}
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/*
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* This takes its configuration only from the module parameters now.
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* See psblk_get_bdev() and blkdev.
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*/
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static int __register_pstore_blk(void)
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static int __register_pstore_blk(const char *devpath)
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{
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char bdev_name[BDEVNAME_SIZE];
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struct block_device *bdev;
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struct pstore_device_info dev;
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struct bdev_info binfo;
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void *holder = blkdev;
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struct pstore_device_info dev = {
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.read = psblk_generic_blk_read,
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.write = psblk_generic_blk_write,
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};
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struct inode *inode;
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int ret = -ENODEV;
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lockdep_assert_held(&pstore_blk_lock);
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/* hold bdev exclusively */
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memset(&binfo, 0, sizeof(binfo));
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bdev = psblk_get_bdev(holder, &binfo);
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if (IS_ERR(bdev)) {
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pr_err("failed to open '%s'!\n", blkdev);
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return PTR_ERR(bdev);
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psblk_file = filp_open(devpath, O_RDWR | O_DSYNC | O_NOATIME | O_EXCL, 0);
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if (IS_ERR(psblk_file)) {
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ret = PTR_ERR(psblk_file);
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pr_err("failed to open '%s': %d!\n", devpath, ret);
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goto err;
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}
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/* only allow driver matching the @blkdev */
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if (!binfo.devt) {
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pr_debug("no major\n");
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ret = -ENODEV;
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goto err_put_bdev;
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inode = file_inode(psblk_file);
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if (!S_ISBLK(inode->i_mode)) {
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pr_err("'%s' is not block device!\n", devpath);
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goto err_fput;
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}
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/* psblk_bdev must be assigned before register to pstore/blk */
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psblk_bdev = bdev;
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memset(&dev, 0, sizeof(dev));
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dev.total_size = binfo.nr_sects << SECTOR_SHIFT;
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dev.read = psblk_generic_blk_read;
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dev.write = psblk_generic_blk_write;
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inode = I_BDEV(psblk_file->f_mapping->host)->bd_inode;
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dev.total_size = i_size_read(inode);
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ret = __register_pstore_device(&dev);
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if (ret)
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goto err_put_bdev;
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goto err_fput;
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bdevname(bdev, bdev_name);
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pr_info("attached %s (no dedicated panic_write!)\n", bdev_name);
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return 0;
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err_put_bdev:
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psblk_bdev = NULL;
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psblk_put_bdev(bdev, holder);
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err_fput:
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fput(psblk_file);
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err:
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psblk_file = NULL;
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return ret;
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}
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static void __unregister_pstore_blk(unsigned int major)
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static void __unregister_pstore_blk(struct file *device)
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{
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struct pstore_device_info dev = { .read = psblk_generic_blk_read };
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void *holder = blkdev;
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lockdep_assert_held(&pstore_blk_lock);
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if (psblk_bdev && MAJOR(psblk_bdev->bd_dev) == major) {
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if (psblk_file && psblk_file == device) {
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__unregister_pstore_device(&dev);
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psblk_put_bdev(psblk_bdev, holder);
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psblk_bdev = NULL;
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fput(psblk_file);
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psblk_file = NULL;
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}
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}
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@ -433,13 +300,48 @@ int pstore_blk_get_config(struct pstore_blk_config *info)
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}
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EXPORT_SYMBOL_GPL(pstore_blk_get_config);
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#ifndef MODULE
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static const char devname[] = "/dev/pstore-blk";
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static __init const char *early_boot_devpath(const char *initial_devname)
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{
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/*
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* During early boot the real root file system hasn't been
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* mounted yet, and no device nodes are present yet. Use the
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* same scheme to find the device that we use for mounting
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* the root file system.
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*/
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dev_t dev = name_to_dev_t(initial_devname);
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if (!dev) {
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pr_err("failed to resolve '%s'!\n", initial_devname);
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return initial_devname;
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}
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init_unlink(devname);
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init_mknod(devname, S_IFBLK | 0600, new_encode_dev(dev));
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return devname;
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}
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#else
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static inline const char *early_boot_devpath(const char *initial_devname)
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{
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return initial_devname;
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}
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#endif
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static int __init pstore_blk_init(void)
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{
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int ret = 0;
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mutex_lock(&pstore_blk_lock);
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if (!pstore_zone_info && best_effort && blkdev[0])
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ret = __register_pstore_blk();
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if (!pstore_zone_info && best_effort && blkdev[0]) {
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ret = __register_pstore_blk(early_boot_devpath(blkdev));
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if (ret == 0 && pstore_zone_info)
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pr_info("attached %s:%s (%zu) (no dedicated panic_write!)\n",
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pstore_zone_info->name, blkdev,
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pstore_zone_info->total_size);
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}
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mutex_unlock(&pstore_blk_lock);
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return ret;
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@ -449,8 +351,8 @@ late_initcall(pstore_blk_init);
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static void __exit pstore_blk_exit(void)
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{
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mutex_lock(&pstore_blk_lock);
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if (psblk_bdev)
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__unregister_pstore_blk(MAJOR(psblk_bdev->bd_dev));
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if (psblk_file)
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__unregister_pstore_blk(psblk_file);
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else {
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struct pstore_device_info dev = { };
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