kernel/linux.git/drivers/mtd/ubi/ubi.h, branch v6.2

ubi: fastmap: Add fastmap control support for 'UBI_IOCATT' ioctl

2022-09-21T16:29:18+00:00

[1] suggests that fastmap is suitable for large flash devices. Module parameter 'fm_autoconvert' is a coarse grained switch to enable all ubi devices to generate fastmap, which may turn on fastmap even for small flash devices. This patch imports a new field 'disable_fm' in struct 'ubi_attach_req' to support following situations by ioctl 'UBI_IOCATT'. [old functions] A. Disable 'fm_autoconvert': Disbable fastmap for all ubi devices B. Enable 'fm_autoconvert': Enable fastmap for all ubi devices [new function] C. Enable 'fm_autoconvert', set 'disable_fm' for given device: Don't create new fastmap and do full scan (existed fastmap will be destroyed) for the given ubi device. A simple test case in [2]. [1] http://www.linux-mtd.infradead.org/doc/ubi.html#L_fastmap [2] https://bugzilla.kernel.org/show_bug.cgi?id=216278 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: Fix repeated words in comments

2022-09-21T09:32:27+00:00

Delete the redundant word 'a'. Delete the redundant word 'the'. Signed-off-by: Jilin Yuan Signed-off-by: Richard Weinberger

ubi: fastmap: Fix high cpu usage of ubi_bgt by making sure wl_pool not empty

2022-05-27T14:46:02+00:00

There at least 6 PEBs reserved on UBI device: 1. EBA_RESERVED_PEBS[1] 2. WL_RESERVED_PEBS[1] 3. UBI_LAYOUT_VOLUME_EBS[2] 4. MIN_FASTMAP_RESERVED_PEBS[2] When all ubi volumes take all their PEBs, there are 3 (EBA_RESERVED_PEBS + WL_RESERVED_PEBS + MIN_FASTMAP_RESERVED_PEBS - MIN_FASTMAP_TAKEN_PEBS[1]) free PEBs. Since commit f9c34bb529975fe ("ubi: Fix producing anchor PEBs") and commit 4b68bf9a69d22dd ("ubi: Select fastmap anchor PEBs considering wear level rules") applied, there is only 1 (3 - FASTMAP_ANCHOR_PEBS[1] - FASTMAP_NEXT_ANCHOR_PEBS[1]) free PEB to fill pool and wl_pool, after filling pool, wl_pool is always empty. So, UBI could be stuck in an infinite loop: ubi_thread system_wq wear_leveling_worker <-------------------------------------------------- get_peb_for_wl | // fm_wl_pool, used = size = 0 | schedule_work(&ubi->fm_work) | | update_fastmap_work_fn | ubi_update_fastmap | ubi_refill_pools | // ubi->free_count - ubi->beb_rsvd_pebs < 5 | // wl_pool is not filled with any PEBs | schedule_erase(old_fm_anchor) | ubi_ensure_anchor_pebs | __schedule_ubi_work(wear_leveling_worker) | | __erase_worker | ensure_wear_leveling | __schedule_ubi_work(wear_leveling_worker) -------------------------- , which cause high cpu usage of ubi_bgt: top - 12:10:42 up 5 min, 2 users, load average: 1.76, 0.68, 0.27 Tasks: 123 total, 3 running, 54 sleeping, 0 stopped, 0 zombie PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1589 root 20 0 0 0 0 R 45.0 0.0 0:38.86 ubi_bgt0d 319 root 20 0 0 0 0 I 15.2 0.0 0:15.29 kworker/0:3-eve 371 root 20 0 0 0 0 I 14.9 0.0 0:12.85 kworker/3:3-eve 20 root 20 0 0 0 0 I 11.3 0.0 0:05.33 kworker/1:0-eve 202 root 20 0 0 0 0 I 11.3 0.0 0:04.93 kworker/2:3-eve In commit 4b68bf9a69d22dd ("ubi: Select fastmap anchor PEBs considering wear level rules"), there are three key changes: 1) Choose the fastmap anchor when the most free PEBs are available. 2) Enable anchor move within the anchor area again as it is useful for distributing wear. 3) Import a candidate fm anchor and check this PEB's erase count during wear leveling. If the wear leveling limit is exceeded, use the used anchor area PEB with the lowest erase count to replace it. The anchor candidate can be removed, we can check fm_anchor PEB's erase count during wear leveling. Fix it by: 1) Removing 'fm_next_anchor' and check 'fm_anchor' during wear leveling. 2) Preferentially filling one free peb into fm_wl_pool in condition of ubi->free_count > ubi->beb_rsvd_pebs, then try to reserve enough free count for fastmap non anchor pebs after the above prerequisites are met. Then, there are at least 1 PEB in pool and 1 PEB in wl_pool after calling ubi_refill_pools() with all erase works done. Fetch a reproducer in [Link]. Fixes: 4b68bf9a69d22dd ("ubi: Select fastmap anchor PEBs ... rules") Link: https://bugzilla.kernel.org/show_bug.cgi?id=215407 Signed-off-by: Zhihao Cheng Signed-off-by: Richard Weinberger

ubi: Remove unnecessary struct declaration

2021-04-15T20:01:25+00:00

struct ubi_wl_entry is defined at 178th line. The declaration here is unnecessary. Remove it. Reviewed-by: Tudor Ambarus Signed-off-by: Wan Jiabing Signed-off-by: Richard Weinberger

Merge tag 'for-linus-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs

2020-06-10T20:24:40+00:00

Pull UBI update from Richard Weinberger: "This contains a single change for UBI: - Select fastmap anchor PEBs considering wear level rules" * tag 'for-linus-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs: ubi: Select fastmap anchor PEBs considering wear level rules

mm: introduce include/linux/pgtable.h

2020-06-09T16:39:13+00:00

The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brian Cain Cc: Catalin Marinas Cc: Chris Zankel Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Guan Xuetao Cc: Guo Ren Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ley Foon Tan Cc: Mark Salter Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Nick Hu Cc: Paul Walmsley Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vincent Chen Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds

ubi: Select fastmap anchor PEBs considering wear level rules

2020-06-02T20:53:05+00:00

There is a risk that the fastmap anchor PEB is alternating between just two PEBs, the current anchor and the previous anchor that was just deleted. As the fastmap pools gets the first take on free PEBs, the pools may leave no free PEBs to be selected as the new anchor, resulting in the two PEBs alternating behaviour. If the anchor PEBs gets a high erase count the PEBs will not be used by the pools but remain in ubi->free, even more increasing the likelihood they will be used as anchors. Getting stuck using only a couple of PEBs continuously will result in an uneven wear, eventually leading to failure. To fix this: - Choose the fastmap anchor when the most free PEBs are available. This is during rebuilding of the fastmap pools, after the unused pool PEBs are added to ubi->free but before the pools are populated again from the free PEBs. Also reserve an additional second best PEB as a candidate for the next time the fast map anchor is updated. If a better PEB is found the next time the fast map anchor is updated, the candidate is made available for building the pools. - Enable anchor move within the anchor area again as it is useful for distributing wear. - The anchor candidate for the next fastmap update is the most suited free PEB. Check this PEB's erase count during wear leveling. If the wear leveling limit is exceeded, the PEB is considered unsuitable for now. As all other non used anchor area PEBs should be even worse, free up the used anchor area PEB with the lowest erase count. Signed-off-by: Arne Edholm Signed-off-by: Richard Weinberger

ubi: Free the normal volumes in error paths of ubi_attach_mtd_dev()

2020-01-16T22:35:59+00:00

The allocated normal volumes saved in ubi->volumes are not freed in the error paths in ubi_attach_mtd_dev() and its callees (e.g. ubi_attach() and ubi_read_volume_table()). These normal volumes should be freed through kill_volumes() and vol_release(), but ubi_attach_mtd_dev() may fail before calling uif_init(), and there will be memory leaks. So adding a new helper ubi_free_all_volumes() to free the normal and the internal volumes. And in order to prevent double-free of volume, reset ubi->volumes[i] to NULL after freeing. Signed-off-by: Hou Tao Signed-off-by: Richard Weinberger

ubi: Fix producing anchor PEBs

2019-11-17T21:45:57+00:00

When a new fastmap is about to be written UBI must make sure it has a free block for a fastmap anchor available. For this ubi_update_fastmap() calls ubi_ensure_anchor_pebs(). This stopped working with 2e8f08deabbc ("ubi: Fix races around ubi_refill_pools()"), with this commit the wear leveling code is blocked and can no longer produce free PEBs. UBI then more often than not falls back to write the new fastmap anchor to the same block it was already on which means the same erase block gets erased during each fastmap write and wears out quite fast. As the locking prevents us from producing the anchor PEB when we actually need it, this patch changes the strategy for creating the anchor PEB. We no longer create it on demand right before we want to write a fastmap, but instead we create an anchor PEB right after we have written a fastmap. This gives us enough time to produce a new anchor PEB before it is needed. To make sure we have an anchor PEB for the very first fastmap write we call ubi_ensure_anchor_pebs() during initialisation as well. Fixes: 2e8f08deabbc ("ubi: Fix races around ubi_refill_pools()") Signed-off-by: Sascha Hauer Signed-off-by: Richard Weinberger

ubi: Fix warning static is not at beginning of declaration

2019-11-17T21:15:08+00:00

Compiler generates following warning when kernel is built with W=1: drivers/mtd/ubi/ubi.h:971:1: warning: ‘static’ is not at beginning of declaration [-Wold-style-declaration] This commit fixes this by correctly ordering keywords. Signed-off-by: Rishi Gupta Signed-off-by: Richard Weinberger