diff options
| -rw-r--r-- | Documentation/admin-guide/pstore-blk.rst | 14 | ||||
| -rw-r--r-- | drivers/mtd/mtdpstore.c | 10 | ||||
| -rw-r--r-- | fs/pstore/blk.c | 403 | ||||
| -rw-r--r-- | include/linux/pstore_blk.h | 27 |
4 files changed, 171 insertions, 283 deletions
diff --git a/Documentation/admin-guide/pstore-blk.rst b/Documentation/admin-guide/pstore-blk.rst index 49d8149f8d32..2d22ead9520e 100644 --- a/Documentation/admin-guide/pstore-blk.rst +++ b/Documentation/admin-guide/pstore-blk.rst @@ -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: diff --git a/drivers/mtd/mtdpstore.c b/drivers/mtd/mtdpstore.c index a3ae8778f6a9..e13d42c0acb0 100644 --- a/drivers/mtd/mtdpstore.c +++ b/drivers/mtd/mtdpstore.c @@ -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) { diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c index 4bb8a344957a..04ce58c939a0 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); @@ -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 - - 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; - - ret = register_pstore_zone(pstore_zone_info); - if (ret) { - kfree(pstore_zone_info); - pstore_zone_info = NULL; - } + dev->zone.max_reason = max_reason; + + /* 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; + 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; } } @@ -205,204 +185,59 @@ 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; - - 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->zone.total_size = i_size_read(inode); - 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); - return ret; -} - -static void __unregister_pstore_blk(unsigned int major) -{ - struct pstore_device_info dev = { .read = psblk_generic_blk_read }; - void *holder = blkdev; +err_fput: + fput(psblk_file); +err: + psblk_file = NULL; - 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; - } + return ret; } /* get information of pstore/blk */ @@ -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); diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h index 99564f93d774..924ca07aafbd 100644 --- a/include/linux/pstore_blk.h +++ b/include/linux/pstore_blk.h @@ -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); |