From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/mtd/mtd_blkdevs.c | 542 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 542 insertions(+) create mode 100644 drivers/mtd/mtd_blkdevs.c (limited to 'drivers/mtd/mtd_blkdevs.c') diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c new file mode 100644 index 000000000..4d2e7b777 --- /dev/null +++ b/drivers/mtd/mtd_blkdevs.c @@ -0,0 +1,542 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Interface to Linux block layer for MTD 'translation layers'. + * + * Copyright © 2003-2010 David Woodhouse + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "mtdcore.h" + +static LIST_HEAD(blktrans_majors); + +static void blktrans_dev_release(struct kref *kref) +{ + struct mtd_blktrans_dev *dev = + container_of(kref, struct mtd_blktrans_dev, ref); + + put_disk(dev->disk); + blk_mq_free_tag_set(dev->tag_set); + kfree(dev->tag_set); + list_del(&dev->list); + kfree(dev); +} + +static void blktrans_dev_put(struct mtd_blktrans_dev *dev) +{ + kref_put(&dev->ref, blktrans_dev_release); +} + + +static blk_status_t do_blktrans_request(struct mtd_blktrans_ops *tr, + struct mtd_blktrans_dev *dev, + struct request *req) +{ + struct req_iterator iter; + struct bio_vec bvec; + unsigned long block, nsect; + char *buf; + + block = blk_rq_pos(req) << 9 >> tr->blkshift; + nsect = blk_rq_cur_bytes(req) >> tr->blkshift; + + switch (req_op(req)) { + case REQ_OP_FLUSH: + if (tr->flush(dev)) + return BLK_STS_IOERR; + return BLK_STS_OK; + case REQ_OP_DISCARD: + if (tr->discard(dev, block, nsect)) + return BLK_STS_IOERR; + return BLK_STS_OK; + case REQ_OP_READ: + buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); + for (; nsect > 0; nsect--, block++, buf += tr->blksize) { + if (tr->readsect(dev, block, buf)) { + kunmap(bio_page(req->bio)); + return BLK_STS_IOERR; + } + } + kunmap(bio_page(req->bio)); + + rq_for_each_segment(bvec, req, iter) + flush_dcache_page(bvec.bv_page); + return BLK_STS_OK; + case REQ_OP_WRITE: + if (!tr->writesect) + return BLK_STS_IOERR; + + rq_for_each_segment(bvec, req, iter) + flush_dcache_page(bvec.bv_page); + + buf = kmap(bio_page(req->bio)) + bio_offset(req->bio); + for (; nsect > 0; nsect--, block++, buf += tr->blksize) { + if (tr->writesect(dev, block, buf)) { + kunmap(bio_page(req->bio)); + return BLK_STS_IOERR; + } + } + kunmap(bio_page(req->bio)); + return BLK_STS_OK; + default: + return BLK_STS_IOERR; + } +} + +int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) +{ + return dev->bg_stop; +} +EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); + +static struct request *mtd_next_request(struct mtd_blktrans_dev *dev) +{ + struct request *rq; + + rq = list_first_entry_or_null(&dev->rq_list, struct request, queuelist); + if (rq) { + list_del_init(&rq->queuelist); + blk_mq_start_request(rq); + return rq; + } + + return NULL; +} + +static void mtd_blktrans_work(struct mtd_blktrans_dev *dev) + __releases(&dev->queue_lock) + __acquires(&dev->queue_lock) +{ + struct mtd_blktrans_ops *tr = dev->tr; + struct request *req = NULL; + int background_done = 0; + + while (1) { + blk_status_t res; + + dev->bg_stop = false; + if (!req && !(req = mtd_next_request(dev))) { + if (tr->background && !background_done) { + spin_unlock_irq(&dev->queue_lock); + mutex_lock(&dev->lock); + tr->background(dev); + mutex_unlock(&dev->lock); + spin_lock_irq(&dev->queue_lock); + /* + * Do background processing just once per idle + * period. + */ + background_done = !dev->bg_stop; + continue; + } + break; + } + + spin_unlock_irq(&dev->queue_lock); + + mutex_lock(&dev->lock); + res = do_blktrans_request(dev->tr, dev, req); + mutex_unlock(&dev->lock); + + if (!blk_update_request(req, res, blk_rq_cur_bytes(req))) { + __blk_mq_end_request(req, res); + req = NULL; + } + + background_done = 0; + cond_resched(); + spin_lock_irq(&dev->queue_lock); + } +} + +static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct mtd_blktrans_dev *dev; + + dev = hctx->queue->queuedata; + if (!dev) { + blk_mq_start_request(bd->rq); + return BLK_STS_IOERR; + } + + spin_lock_irq(&dev->queue_lock); + list_add_tail(&bd->rq->queuelist, &dev->rq_list); + mtd_blktrans_work(dev); + spin_unlock_irq(&dev->queue_lock); + + return BLK_STS_OK; +} + +static int blktrans_open(struct gendisk *disk, blk_mode_t mode) +{ + struct mtd_blktrans_dev *dev = disk->private_data; + int ret = 0; + + kref_get(&dev->ref); + + mutex_lock(&dev->lock); + + if (dev->open) + goto unlock; + + __module_get(dev->tr->owner); + + if (!dev->mtd) + goto unlock; + + if (dev->tr->open) { + ret = dev->tr->open(dev); + if (ret) + goto error_put; + } + + ret = __get_mtd_device(dev->mtd); + if (ret) + goto error_release; + dev->writable = mode & BLK_OPEN_WRITE; + +unlock: + dev->open++; + mutex_unlock(&dev->lock); + return ret; + +error_release: + if (dev->tr->release) + dev->tr->release(dev); +error_put: + module_put(dev->tr->owner); + mutex_unlock(&dev->lock); + blktrans_dev_put(dev); + return ret; +} + +static void blktrans_release(struct gendisk *disk) +{ + struct mtd_blktrans_dev *dev = disk->private_data; + + mutex_lock(&dev->lock); + + if (--dev->open) + goto unlock; + + module_put(dev->tr->owner); + + if (dev->mtd) { + if (dev->tr->release) + dev->tr->release(dev); + __put_mtd_device(dev->mtd); + } +unlock: + mutex_unlock(&dev->lock); + blktrans_dev_put(dev); +} + +static int blktrans_getgeo(struct gendisk *disk, struct hd_geometry *geo) +{ + struct mtd_blktrans_dev *dev = disk->private_data; + int ret = -ENXIO; + + mutex_lock(&dev->lock); + + if (!dev->mtd) + goto unlock; + + ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY; +unlock: + mutex_unlock(&dev->lock); + return ret; +} + +static const struct block_device_operations mtd_block_ops = { + .owner = THIS_MODULE, + .open = blktrans_open, + .release = blktrans_release, + .getgeo = blktrans_getgeo, +}; + +static const struct blk_mq_ops mtd_mq_ops = { + .queue_rq = mtd_queue_rq, +}; + +int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) +{ + struct mtd_blktrans_ops *tr = new->tr; + struct mtd_blktrans_dev *d; + struct queue_limits lim = { }; + int last_devnum = -1; + struct gendisk *gd; + int ret; + + lockdep_assert_held(&mtd_table_mutex); + + list_for_each_entry(d, &tr->devs, list) { + if (new->devnum == -1) { + /* Use first free number */ + if (d->devnum != last_devnum+1) { + /* Found a free devnum. Plug it in here */ + new->devnum = last_devnum+1; + list_add_tail(&new->list, &d->list); + goto added; + } + } else if (d->devnum == new->devnum) { + /* Required number taken */ + return -EBUSY; + } else if (d->devnum > new->devnum) { + /* Required number was free */ + list_add_tail(&new->list, &d->list); + goto added; + } + last_devnum = d->devnum; + } + + ret = -EBUSY; + if (new->devnum == -1) + new->devnum = last_devnum+1; + + /* Check that the device and any partitions will get valid + * minor numbers and that the disk naming code below can cope + * with this number. */ + if (new->devnum > (MINORMASK >> tr->part_bits) || + (tr->part_bits && new->devnum >= 27 * 26)) + return ret; + + list_add_tail(&new->list, &tr->devs); + added: + + mutex_init(&new->lock); + kref_init(&new->ref); + if (!tr->writesect) + new->readonly = 1; + + ret = -ENOMEM; + new->tag_set = kzalloc_obj(*new->tag_set); + if (!new->tag_set) + goto out_list_del; + + ret = blk_mq_alloc_sq_tag_set(new->tag_set, &mtd_mq_ops, 2, + BLK_MQ_F_BLOCKING); + if (ret) + goto out_kfree_tag_set; + + lim.logical_block_size = tr->blksize; + if (tr->discard) + lim.max_hw_discard_sectors = UINT_MAX; + if (tr->flush) + lim.features |= BLK_FEAT_WRITE_CACHE; + + /* Create gendisk */ + gd = blk_mq_alloc_disk(new->tag_set, &lim, new); + if (IS_ERR(gd)) { + ret = PTR_ERR(gd); + goto out_free_tag_set; + } + + new->disk = gd; + new->rq = new->disk->queue; + gd->private_data = new; + gd->major = tr->major; + gd->first_minor = (new->devnum) << tr->part_bits; + gd->minors = 1 << tr->part_bits; + gd->fops = &mtd_block_ops; + + if (tr->part_bits) { + if (new->devnum < 26) + snprintf(gd->disk_name, sizeof(gd->disk_name), + "%s%c", tr->name, 'a' + new->devnum); + else + snprintf(gd->disk_name, sizeof(gd->disk_name), + "%s%c%c", tr->name, + 'a' - 1 + new->devnum / 26, + 'a' + new->devnum % 26); + } else { + snprintf(gd->disk_name, sizeof(gd->disk_name), + "%s%d", tr->name, new->devnum); + gd->flags |= GENHD_FL_NO_PART; + } + + set_capacity(gd, ((u64)new->size * tr->blksize) >> 9); + + /* Create the request queue */ + spin_lock_init(&new->queue_lock); + INIT_LIST_HEAD(&new->rq_list); + gd->queue = new->rq; + + if (new->readonly) + set_disk_ro(gd, 1); + + ret = device_add_disk(&new->mtd->dev, gd, NULL); + if (ret) + goto out_cleanup_disk; + + if (new->disk_attributes) { + ret = sysfs_create_group(&disk_to_dev(gd)->kobj, + new->disk_attributes); + WARN_ON(ret); + } + return 0; + +out_cleanup_disk: + put_disk(new->disk); +out_free_tag_set: + blk_mq_free_tag_set(new->tag_set); +out_kfree_tag_set: + kfree(new->tag_set); +out_list_del: + list_del(&new->list); + return ret; +} + +int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) +{ + unsigned long flags; + unsigned int memflags; + + lockdep_assert_held(&mtd_table_mutex); + + if (old->disk_attributes) + sysfs_remove_group(&disk_to_dev(old->disk)->kobj, + old->disk_attributes); + + /* Stop new requests to arrive */ + del_gendisk(old->disk); + + /* Kill current requests */ + spin_lock_irqsave(&old->queue_lock, flags); + old->rq->queuedata = NULL; + spin_unlock_irqrestore(&old->queue_lock, flags); + + /* freeze+quiesce queue to ensure all requests are flushed */ + memflags = blk_mq_freeze_queue(old->rq); + blk_mq_quiesce_queue(old->rq); + blk_mq_unquiesce_queue(old->rq); + blk_mq_unfreeze_queue(old->rq, memflags); + + /* If the device is currently open, tell trans driver to close it, + then put mtd device, and don't touch it again */ + mutex_lock(&old->lock); + if (old->open) { + if (old->tr->release) + old->tr->release(old); + __put_mtd_device(old->mtd); + } + + old->mtd = NULL; + + mutex_unlock(&old->lock); + blktrans_dev_put(old); + return 0; +} + +static void blktrans_notify_remove(struct mtd_info *mtd) +{ + struct mtd_blktrans_ops *tr; + struct mtd_blktrans_dev *dev, *next; + + list_for_each_entry(tr, &blktrans_majors, list) + list_for_each_entry_safe(dev, next, &tr->devs, list) + if (dev->mtd == mtd) + tr->remove_dev(dev); +} + +static void blktrans_notify_add(struct mtd_info *mtd) +{ + struct mtd_blktrans_ops *tr; + + if (mtd->type == MTD_ABSENT || mtd->type == MTD_UBIVOLUME) + return; + + list_for_each_entry(tr, &blktrans_majors, list) + tr->add_mtd(tr, mtd); +} + +static struct mtd_notifier blktrans_notifier = { + .add = blktrans_notify_add, + .remove = blktrans_notify_remove, +}; + +int register_mtd_blktrans(struct mtd_blktrans_ops *tr) +{ + struct mtd_info *mtd; + int ret; + + /* Register the notifier if/when the first device type is + registered, to prevent the link/init ordering from fucking + us over. */ + if (!blktrans_notifier.list.next) + register_mtd_user(&blktrans_notifier); + + ret = register_blkdev(tr->major, tr->name); + if (ret < 0) { + printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", + tr->name, tr->major, ret); + return ret; + } + + if (ret) + tr->major = ret; + + tr->blkshift = ffs(tr->blksize) - 1; + + INIT_LIST_HEAD(&tr->devs); + + mutex_lock(&mtd_table_mutex); + list_add(&tr->list, &blktrans_majors); + mtd_for_each_device(mtd) + if (mtd->type != MTD_ABSENT && mtd->type != MTD_UBIVOLUME) + tr->add_mtd(tr, mtd); + mutex_unlock(&mtd_table_mutex); + return 0; +} + +int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) +{ + struct mtd_blktrans_dev *dev, *next; + + mutex_lock(&mtd_table_mutex); + + /* Remove it from the list of active majors */ + list_del(&tr->list); + + list_for_each_entry_safe(dev, next, &tr->devs, list) + tr->remove_dev(dev); + + mutex_unlock(&mtd_table_mutex); + unregister_blkdev(tr->major, tr->name); + + BUG_ON(!list_empty(&tr->devs)); + return 0; +} + +static void __exit mtd_blktrans_exit(void) +{ + /* No race here -- if someone's currently in register_mtd_blktrans + we're screwed anyway. */ + if (blktrans_notifier.list.next) + unregister_mtd_user(&blktrans_notifier); +} + +module_exit(mtd_blktrans_exit); + +EXPORT_SYMBOL_GPL(register_mtd_blktrans); +EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); +EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); +EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); + +MODULE_AUTHOR("David Woodhouse "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); 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