From 1d1f6cc5818c750ac69473e4951e7165913fbf16 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 15 Jun 2021 10:19:13 -0700 Subject: [PATCH] pstore/blk: Include zone in pstore_device_info Information was redundant between struct pstore_zone_info and struct pstore_device_info. Use struct pstore_zone_info, with member name "zone". Additionally untangle the logic for the "best effort" block device instance. Signed-off-by: Kees Cook Fixed-by: Pu Lehui Link: https://lore.kernel.org/lkml/20210617005424.182305-1-pulehui@huawei.com --- drivers/mtd/mtdpstore.c | 10 +-- fs/pstore/blk.c | 141 ++++++++++++++++++++----------------- include/linux/pstore_blk.h | 27 +------ 3 files changed, 86 insertions(+), 92 deletions(-) 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 c373e0d73e6c..04ce58c939a0 100644 --- a/fs/pstore/blk.c +++ b/fs/pstore/blk.c @@ -70,7 +70,7 @@ MODULE_PARM_DESC(blkdev, "block device for pstore storage"); */ static DEFINE_MUTEX(pstore_blk_lock); static struct file *psblk_file; -static struct pstore_zone_info *pstore_zone_info; +static struct pstore_device_info *pstore_device_info; #define check_size(name, alignsize) ({ \ long _##name_ = (name); \ @@ -91,7 +91,7 @@ static struct pstore_zone_info *pstore_zone_info; _##name_ = 0; \ /* Synchronize module parameters with resuls. */ \ name = _##name_ / 1024; \ - pstore_zone_info->name = _##name_; \ + dev->zone.name = _##name_; \ } static int __register_pstore_device(struct pstore_device_info *dev) @@ -104,50 +104,42 @@ static int __register_pstore_device(struct pstore_device_info *dev) pr_err("NULL device info\n"); return -EINVAL; } - if (!dev->total_size) { + if (!dev->zone.total_size) { pr_err("zero sized device\n"); return -EINVAL; } - if (!dev->read) { + if (!dev->zone.read) { pr_err("no read handler for device\n"); return -EINVAL; } - if (!dev->write) { + 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; + /* 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); + dev->zone.max_reason = max_reason; - 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; + /* 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; - ret = register_pstore_zone(pstore_zone_info); - if (ret) { - kfree(pstore_zone_info); - pstore_zone_info = NULL; - } return ret; } /** @@ -174,10 +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; } } @@ -211,12 +202,9 @@ static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes, /* * This takes its configuration only from the module parameters now. */ -static int __register_pstore_blk(const char *devpath) +static int __register_pstore_blk(struct pstore_device_info *dev, + const char *devpath) { - struct pstore_device_info dev = { - .read = psblk_generic_blk_read, - .write = psblk_generic_blk_write, - }; struct inode *inode; int ret = -ENODEV; @@ -236,9 +224,9 @@ static int __register_pstore_blk(const char *devpath) } inode = I_BDEV(psblk_file->f_mapping->host)->bd_inode; - dev.total_size = i_size_read(inode); + dev->zone.total_size = i_size_read(inode); - ret = __register_pstore_device(&dev); + ret = __register_pstore_device(dev); if (ret) goto err_fput; @@ -252,18 +240,6 @@ static int __register_pstore_blk(const char *devpath) return ret; } -static void __unregister_pstore_blk(struct file *device) -{ - struct pstore_device_info dev = { .read = psblk_generic_blk_read }; - - lockdep_assert_held(&pstore_blk_lock); - if (psblk_file && psblk_file == device) { - __unregister_pstore_device(&dev); - fput(psblk_file); - psblk_file = NULL; - } -} - /* get information of pstore/blk */ int pstore_blk_get_config(struct pstore_blk_config *info) { @@ -308,18 +284,63 @@ static inline const char *early_boot_devpath(const char *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(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); - } + ret = __best_effort_init(); mutex_unlock(&pstore_blk_lock); return ret; @@ -329,15 +350,9 @@ late_initcall(pstore_blk_init); static void __exit pstore_blk_exit(void) { mutex_lock(&pstore_blk_lock); - if (psblk_file) - __unregister_pstore_blk(psblk_file); - 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);