summaryrefslogtreecommitdiff
path: root/fs/iomap
AgeCommit message (Collapse)Author
2024-03-04Merge tag 'vfs-6.9.rw_hint' of ↵Christian Brauner
gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs Pull write hint fix from Christian Brauner: UFS devices are widely used in mobile applications, e.g. in smartphones. UFS vendors need data lifetime information to achieve good performance. Providing data lifetime information to UFS devices can result in up to 40% lower write amplification. Hence this patch series that restores the bi_write_hint member in struct bio. After this patch series has been merged, patches that implement data lifetime support in the SCSI disk (sd) driver will be sent to the Linux kernel SCSI maintainer. The following changes are included in this patch series: - Improvements for the F_GET_RW_HINT and F_SET_RW_HINT fcntls. - Move enum rw_hint into a new header file. - Support F_SET_RW_HINT for block devices to make it easy to test data lifetime support. - Restore the bio.bi_write_hint member and restore support in the VFS layer and also in the block layer for data lifetime information. The shell script that has been used to test the patch series combined with the SCSI patches is available at the end of this cover letter. * tag 'vfs-6.9.rw_hint' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: block, fs: Restore the per-bio/request data lifetime fields fs: Propagate write hints to the struct block_device inode fs: Move enum rw_hint into a new header file fs: Split fcntl_rw_hint() fs: Verify write lifetime constants at compile time fs: Fix rw_hint validation Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21iomap: Add processed for iomap_iterKassey Li
processed: The number of bytes processed by the body in the most recent iteration, or a negative errno. 0 causes the iteration to stop. The processed is useful to check when the loop breaks. Signed-off-by: Kassey Li <quic_yingangl@quicinc.com> Link: https://lore.kernel.org/r/20240219021138.3481763-1-quic_yingangl@quicinc.com Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-21iomap: add pos and dirty_len into trace_iomap_writepage_mapZhang Yi
Since commit fd07e0aa23c4 ("iomap: map multiple blocks at a time"), we could map multi-blocks once a time, and the dirty_len indicates the expected map length, map_len won't large than it. The pos and dirty_len means the dirty range that should be mapped to write, add them into trace_iomap_writepage_map() could be more useful for debug. Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Link: https://lore.kernel.org/r/20240220115759.3445025-1-yi.zhang@huaweicloud.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-06block, fs: Restore the per-bio/request data lifetime fieldsBart Van Assche
Restore support for passing data lifetime information from filesystems to block drivers. This patch reverts commit b179c98f7697 ("block: Remove request.write_hint") and commit c75e707fe1aa ("block: remove the per-bio/request write hint"). This patch does not modify the size of struct bio because the new bi_write_hint member fills a hole in struct bio. pahole reports the following for struct bio on an x86_64 system with this patch applied: /* size: 112, cachelines: 2, members: 20 */ /* sum members: 110, holes: 1, sum holes: 2 */ /* last cacheline: 48 bytes */ Reviewed-by: Kanchan Joshi <joshi.k@samsung.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20240202203926.2478590-7-bvanassche@acm.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: pass the length of the dirty region to ->map_blocksChristoph Hellwig
Let the file system know how much dirty data exists at the passed in offset. This allows file systems to allocate the right amount of space that actually is written back if they can't eagerly convert (e.g. because they don't support unwritten extents). Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-15-hch@lst.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: map multiple blocks at a timeChristoph Hellwig
The ->map_blocks interface returns a valid range for writeback, but we still call back into it for every block, which is a bit inefficient. Change iomap_writepage_map to use the valid range in the map until the end of the folio or the dirty range inside the folio instead of calling back into every block. Note that the range is not used over folio boundaries as we need to be able to check the mapping sequence count under the folio lock. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-14-hch@lst.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: submit ioends immediatelyChristoph Hellwig
Currently the writeback code delays submitting fill ioends until we reach the end of the folio. The reason for that is that otherwise the end I/O handler could clear the writeback bit before we've even finished submitting all I/O for the folio. Add a bias to ifs->write_bytes_pending while we are submitting I/O for a folio so that it never reaches zero until all I/O is completed to prevent the early writeback bit clearing, and remove the now superfluous submit_list. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-13-hch@lst.de Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: factor out a iomap_writepage_map_block helperChristoph Hellwig
Split the loop body that calls into the file system to map a block and add it to the ioend into a separate helper to prefer for refactoring of the surrounding code. Note that this was the only place in iomap_writepage_map that could return an error, so include the call to ->discard_folio into the new helper as that will help to avoid code duplication in the future. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-12-hch@lst.de Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: only call mapping_set_error once for each failed bioChristoph Hellwig
Instead of clling mapping_set_error once per folio, only do that once per bio, and consolidate all the writeback error handling code in iomap_finish_ioend. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-11-hch@lst.de Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: don't chain biosChristoph Hellwig
Back in the days when a single bio could only be filled to the hardware limits, and we scheduled a work item for each bio completion, chaining multiple bios for a single ioend made a lot of sense to reduce the number of completions. But these days bios can be filled until we reach the number of vectors or total size limit, which means we can always fit at least 1 megabyte worth of data in the worst case, but usually a lot more due to large folios. The only thing bio chaining is buying us now is to reduce the size of the allocation from an ioend with an embedded bio into a plain bio, which is a 52 bytes differences on 64-bit systems. This is not worth the added complexity, so remove the bio chaining and only use the bio embedded into the ioend. This will help to simplify further changes to the iomap writeback code. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-10-hch@lst.de Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: move the iomap_sector sector calculation out of iomap_add_to_ioendChristoph Hellwig
The calculation in iomap_sector is pretty trivial and most of the time iomap_add_to_ioend only callers either iomap_can_add_to_ioend or iomap_alloc_ioend from a single invocation. Calculate the sector in the two lower level functions and stop passing it from iomap_add_to_ioend and update the iomap_alloc_ioend argument passing order to match that of iomap_add_to_ioend. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-9-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: clean up the iomap_alloc_ioend calling conventionChristoph Hellwig
Switch to the same argument order as iomap_writepage_map and remove the ifs argument that can be trivially recalculated. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-8-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: move all remaining per-folio logic into iomap_writepage_mapChristoph Hellwig
Move the tracepoint and the iomap check from iomap_do_writepage into iomap_writepage_map. This keeps all logic in one places, and leaves iomap_do_writepage just as the wrapper for the callback conventions of write_cache_pages, which will go away when that is converted to an iterator. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-7-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: factor out a iomap_writepage_handle_eof helperChristoph Hellwig
Most of iomap_do_writepage is dedidcated to handling a folio crossing or beyond i_size. Split this is into a separate helper and update the commens to deal with folios instead of pages and make them more readable. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-6-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: move the PF_MEMALLOC check to iomap_writepagesChristoph Hellwig
The iomap writepage implementation has been removed in commit 478af190cb6c ("iomap: remove iomap_writepage") and this code is now only called through ->writepages which never happens from memory reclaim. Nove the check from iomap_do_writepage to iomap_writepages so that is only called once per ->writepage invocation. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-5-hch@lst.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: move the io_folios field out of struct iomap_ioendChristoph Hellwig
The io_folios member in struct iomap_ioend counts the number of folios added to an ioend. It is only used at submission time and can thus be moved to iomap_writepage_ctx instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-4-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: treat inline data in iomap_writepage_map as an I/O errorChristoph Hellwig
iomap_writepage_map aready warns about inline data, but then just ignores it. Treat it as an error and return -EIO. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-3-hch@lst.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-02-01iomap: clear the per-folio dirty bits on all writeback failuresChristoph Hellwig
write_cache_pages always clear the page dirty bit before calling into the file systems, and leaves folios with a writeback failure without the dirty bit after return. We also clear the per-block writeback bits for writeback failures unless no I/O has submitted, which will leave the folio in an inconsistent state where it doesn't have the folio dirty, but one or more per-block dirty bits. This seems to be due the place where the iomap_clear_range_dirty call was inserted into the existing not very clearly structured code when adding per-block dirty bit support and not actually intentional. Switch to always clearing the dirty on writeback failure. Fixes: 4ce02c679722 ("iomap: Add per-block dirty state tracking to improve performance") Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231207072710.176093-2-hch@lst.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-10mm: add folio_fill_tail() and use it in iomapMatthew Wilcox (Oracle)
The iomap code was limited to PAGE_SIZE bytes; generalise it to cover an arbitrary-sized folio, and move it to be a common helper. [akpm@linux-foundation.org: fix folio_fill_tail(), per Andreas Gruenbacher] Link: https://lkml.kernel.org/r/20231107212643.3490372-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-11-02Merge tag 'mm-stable-2023-11-01-14-33' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Many singleton patches against the MM code. The patch series which are included in this merge do the following: - Kemeng Shi has contributed some compation maintenance work in the series 'Fixes and cleanups to compaction' - Joel Fernandes has a patchset ('Optimize mremap during mutual alignment within PMD') which fixes an obscure issue with mremap()'s pagetable handling during a subsequent exec(), based upon an implementation which Linus suggested - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the following patch series: mm/damon: misc fixups for documents, comments and its tracepoint mm/damon: add a tracepoint for damos apply target regions mm/damon: provide pseudo-moving sum based access rate mm/damon: implement DAMOS apply intervals mm/damon/core-test: Fix memory leaks in core-test mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval - In the series 'Do not try to access unaccepted memory' Adrian Hunter provides some fixups for the recently-added 'unaccepted memory' feature. To increase the feature's checking coverage. 'Plug a few gaps where RAM is exposed without checking if it is unaccepted memory' - In the series 'cleanups for lockless slab shrink' Qi Zheng has done some maintenance work which is preparation for the lockless slab shrinking code - Qi Zheng has redone the earlier (and reverted) attempt to make slab shrinking lockless in the series 'use refcount+RCU method to implement lockless slab shrink' - David Hildenbrand contributes some maintenance work for the rmap code in the series 'Anon rmap cleanups' - Kefeng Wang does more folio conversions and some maintenance work in the migration code. Series 'mm: migrate: more folio conversion and unification' - Matthew Wilcox has fixed an issue in the buffer_head code which was causing long stalls under some heavy memory/IO loads. Some cleanups were added on the way. Series 'Add and use bdev_getblk()' - In the series 'Use nth_page() in place of direct struct page manipulation' Zi Yan has fixed a potential issue with the direct manipulation of hugetlb page frames - In the series 'mm: hugetlb: Skip initialization of gigantic tail struct pages if freed by HVO' has improved our handling of gigantic pages in the hugetlb vmmemmep optimizaton code. This provides significant boot time improvements when significant amounts of gigantic pages are in use - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code rationalization and folio conversions in the hugetlb code - Yin Fengwei has improved mlock()'s handling of large folios in the series 'support large folio for mlock' - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has added statistics for memcg v1 users which are available (and useful) under memcg v2 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable) prctl so that userspace may direct the kernel to not automatically propagate the denial to child processes. The series is named 'MDWE without inheritance' - Kefeng Wang has provided the series 'mm: convert numa balancing functions to use a folio' which does what it says - In the series 'mm/ksm: add fork-exec support for prctl' Stefan Roesch makes is possible for a process to propagate KSM treatment across exec() - Huang Ying has enhanced memory tiering's calculation of memory distances. This is used to permit the dax/kmem driver to use 'high bandwidth memory' in addition to Optane Data Center Persistent Memory Modules (DCPMM). The series is named 'memory tiering: calculate abstract distance based on ACPI HMAT' - In the series 'Smart scanning mode for KSM' Stefan Roesch has optimized KSM by teaching it to retain and use some historical information from previous scans - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the series 'mm: memcg: fix tracking of pending stats updates values' - In the series 'Implement IOCTL to get and optionally clear info about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap which permits us to atomically read-then-clear page softdirty state. This is mainly used by CRIU - Hugh Dickins contributed the series 'shmem,tmpfs: general maintenance', a bunch of relatively minor maintenance tweaks to this code - Matthew Wilcox has increased the use of the VMA lock over file-backed page faults in the series 'Handle more faults under the VMA lock'. Some rationalizations of the fault path became possible as a result - In the series 'mm/rmap: convert page_move_anon_rmap() to folio_move_anon_rmap()' David Hildenbrand has implemented some cleanups and folio conversions - In the series 'various improvements to the GUP interface' Lorenzo Stoakes has simplified and improved the GUP interface with an eye to providing groundwork for future improvements - Andrey Konovalov has sent along the series 'kasan: assorted fixes and improvements' which does those things - Some page allocator maintenance work from Kemeng Shi in the series 'Two minor cleanups to break_down_buddy_pages' - In thes series 'New selftest for mm' Breno Leitao has developed another MM self test which tickles a race we had between madvise() and page faults - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups and an optimization to the core pagecache code - Nhat Pham has added memcg accounting for hugetlb memory in the series 'hugetlb memcg accounting' - Cleanups and rationalizations to the pagemap code from Lorenzo Stoakes, in the series 'Abstract vma_merge() and split_vma()' - Audra Mitchell has fixed issues in the procfs page_owner code's new timestamping feature which was causing some misbehaviours. In the series 'Fix page_owner's use of free timestamps' - Lorenzo Stoakes has fixed the handling of new mappings of sealed files in the series 'permit write-sealed memfd read-only shared mappings' - Mike Kravetz has optimized the hugetlb vmemmap optimization in the series 'Batch hugetlb vmemmap modification operations' - Some buffer_head folio conversions and cleanups from Matthew Wilcox in the series 'Finish the create_empty_buffers() transition' - As a page allocator performance optimization Huang Ying has added automatic tuning to the allocator's per-cpu-pages feature, in the series 'mm: PCP high auto-tuning' - Roman Gushchin has contributed the patchset 'mm: improve performance of accounted kernel memory allocations' which improves their performance by ~30% as measured by a micro-benchmark - folio conversions from Kefeng Wang in the series 'mm: convert page cpupid functions to folios' - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about kmemleak' - Qi Zheng has improved our handling of memoryless nodes by keeping them off the allocation fallback list. This is done in the series 'handle memoryless nodes more appropriately' - khugepaged conversions from Vishal Moola in the series 'Some khugepaged folio conversions'" [ bcachefs conflicts with the dynamically allocated shrinkers have been resolved as per Stephen Rothwell in https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/ with help from Qi Zheng. The clone3 test filtering conflict was half-arsed by yours truly ] * tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits) mm/damon/sysfs: update monitoring target regions for online input commit mm/damon/sysfs: remove requested targets when online-commit inputs selftests: add a sanity check for zswap Documentation: maple_tree: fix word spelling error mm/vmalloc: fix the unchecked dereference warning in vread_iter() zswap: export compression failure stats Documentation: ubsan: drop "the" from article title mempolicy: migration attempt to match interleave nodes mempolicy: mmap_lock is not needed while migrating folios mempolicy: alloc_pages_mpol() for NUMA policy without vma mm: add page_rmappable_folio() wrapper mempolicy: remove confusing MPOL_MF_LAZY dead code mempolicy: mpol_shared_policy_init() without pseudo-vma mempolicy trivia: use pgoff_t in shared mempolicy tree mempolicy trivia: slightly more consistent naming mempolicy trivia: delete those ancient pr_debug()s mempolicy: fix migrate_pages(2) syscall return nr_failed kernfs: drop shared NUMA mempolicy hooks hugetlbfs: drop shared NUMA mempolicy pretence mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets() ...
2023-10-19iomap: fix short copy in iomap_write_iter()Jan Stancek
Starting with commit 5d8edfb900d5 ("iomap: Copy larger chunks from userspace"), iomap_write_iter() can get into endless loop. This can be reproduced with LTP writev07 which uses partially valid iovecs: struct iovec wr_iovec[] = { { buffer, 64 }, { bad_addr, 64 }, { buffer + 64, 64 }, { buffer + 64 * 2, 64 }, }; commit bc1bb416bbb9 ("generic_perform_write()/iomap_write_actor(): saner logics for short copy") previously introduced the logic, which made short copy retry in next iteration with amount of "bytes" it managed to copy: if (unlikely(status == 0)) { /* * A short copy made iomap_write_end() reject the * thing entirely. Might be memory poisoning * halfway through, might be a race with munmap, * might be severe memory pressure. */ if (copied) bytes = copied; However, since 5d8edfb900d5 "bytes" is no longer carried into next iteration, because it is now always initialized at the beginning of the loop. And for iov_iter_count < PAGE_SIZE, "bytes" ends up with same value as previous iteration, making the loop retry same copy over and over, which leads to writev07 testcase hanging. Make next iteration retry with amount of bytes we managed to copy. Fixes: 5d8edfb900d5 ("iomap: Copy larger chunks from userspace") Signed-off-by: Jan Stancek <jstancek@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-10-18iomap: use folio_end_read()Matthew Wilcox (Oracle)
Combine the setting of the uptodate flag with the clearing of the locked flag. Link: https://lkml.kernel.org/r/20231004165317.1061855-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18iomap: protect read_bytes_pending with the state_lockMatthew Wilcox (Oracle)
Perform one atomic operation (acquiring the spinlock) instead of two (spinlock & atomic_sub) per read completion. Link: https://lkml.kernel.org/r/20231004165317.1061855-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18iomap: hold state_lock over call to ifs_set_range_uptodate()Matthew Wilcox (Oracle)
Patch series "Add folio_end_read", v2. The core of this patchset is the new folio_end_read() call which filesystems can use when finishing a page cache read instead of separate calls to mark the folio uptodate and unlock it. As an illustration of its use, I converted ext4, iomap & mpage; more can be converted. I think that's useful by itself, but the interesting optimisation is that we can implement that with a single XOR instruction that sets the uptodate bit, clears the lock bit, tests the waiter bit and provides a write memory barrier. That removes one memory barrier and one atomic instruction from each page read, which seems worth doing. That's in patch 15. The last two patches could be a separate series, but basically we can do the same thing with the writeback flag that we do with the unlock flag; clear it and test the waiters bit at the same time. This patch (of 17): This is really preparation for the next patch, but it lets us call folio_mark_uptodate() in just one place instead of two. Link: https://lkml.kernel.org/r/20231004165317.1061855-1-willy@infradead.org Link: https://lkml.kernel.org/r/20231004165317.1061855-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-09-28iomap: Spelling s/preceeding/preceding/gGeert Uytterhoeven
Fix a misspelling of "preceding". Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Bill O'Donnell <bodonnel@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-09-19iomap: convert iomap_unshare_iter to use large foliosDarrick J. Wong
Convert iomap_unshare_iter to create large folios if possible, since the write and zeroing paths already do that. I think this got missed in the conversion of the write paths that landed in 6.6-rc1. Cc: ritesh.list@gmail.com, willy@infradead.org Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
2023-09-18iomap: don't skip reading in !uptodate folios when unsharing a rangeDarrick J. Wong
Prior to commit a01b8f225248e, we would always read in the contents of a !uptodate folio prior to writing userspace data into the folio, allocated a folio state object, etc. Ritesh introduced an optimization that skips all of that if the write would cover the entire folio. Unfortunately, the optimization misses the unshare case, where we always have to read in the folio contents since there isn't a data buffer supplied by userspace. This can result in stale kernel memory exposure if userspace issues a FALLOC_FL_UNSHARE_RANGE call on part of a shared file that isn't already cached. This was caught by observing fstests regressions in the "unshare around" mechanism that is used for unaligned writes to a reflinked realtime volume when the realtime extent size is larger than 1FSB, though I think it applies to any shared file. Cc: ritesh.list@gmail.com, willy@infradead.org Fixes: a01b8f225248e ("iomap: Allocate ifs in ->write_begin() early") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
2023-08-29Merge tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: "Pretty quiet round for this release. This contains: - Add support for zoned storage to ublk (Andreas, Ming) - Series improving performance for drivers that mark themselves as needing a blocking context for issue (Bart) - Cleanup the flush logic (Chengming) - sed opal keyring support (Greg) - Fixes and improvements to the integrity support (Jinyoung) - Add some exports for bcachefs that we can hopefully delete again in the future (Kent) - deadline throttling fix (Zhiguo) - Series allowing building the kernel without buffer_head support (Christoph) - Sanitize the bio page adding flow (Christoph) - Write back cache fixes (Christoph) - MD updates via Song: - Fix perf regression for raid0 large sequential writes (Jan) - Fix split bio iostat for raid0 (David) - Various raid1 fixes (Heinz, Xueshi) - raid6test build fixes (WANG) - Deprecate bitmap file support (Christoph) - Fix deadlock with md sync thread (Yu) - Refactor md io accounting (Yu) - Various non-urgent fixes (Li, Yu, Jack) - Various fixes and cleanups (Arnd, Azeem, Chengming, Damien, Li, Ming, Nitesh, Ruan, Tejun, Thomas, Xu)" * tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux: (113 commits) block: use strscpy() to instead of strncpy() block: sed-opal: keyring support for SED keys block: sed-opal: Implement IOC_OPAL_REVERT_LSP block: sed-opal: Implement IOC_OPAL_DISCOVERY blk-mq: prealloc tags when increase tagset nr_hw_queues blk-mq: delete redundant tagset map update when fallback blk-mq: fix tags leak when shrink nr_hw_queues ublk: zoned: support REQ_OP_ZONE_RESET_ALL md: raid0: account for split bio in iostat accounting md/raid0: Fix performance regression for large sequential writes md/raid0: Factor out helper for mapping and submitting a bio md raid1: allow writebehind to work on any leg device set WriteMostly md/raid1: hold the barrier until handle_read_error() finishes md/raid1: free the r1bio before waiting for blocked rdev md/raid1: call free_r1bio() before allow_barrier() in raid_end_bio_io() blk-cgroup: Fix NULL deref caused by blkg_policy_data being installed before init drivers/rnbd: restore sysfs interface to rnbd-client md/raid5-cache: fix null-ptr-deref for r5l_flush_stripe_to_raid() raid6: test: only check for Altivec if building on powerpc hosts raid6: test: make sure all intermediate and artifact files are .gitignored ...
2023-08-02fs: rename and move block_page_mkwrite_returnChristoph Hellwig
block_page_mkwrite_return is neither block nor mkwrite specific, and should not be under CONFIG_BLOCK. Move it to mm.h and rename it to vmf_fs_error. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230801172201.1923299-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-08-01Merge tag 'xfs-async-dio.6-2023-08-01' of git://git.kernel.dk/linux into ↵Darrick J. Wong
iomap-6.6-mergeA Improve iomap/xfs async dio write performance iomap always punts async dio write completions to a workqueue, which has a cost in terms of efficiency (now you need an unrelated worker to process it) and latency (now you're bouncing a completion through an async worker, which is a classic slowdown scenario). io_uring handles IRQ completions via task_work, and for writes that don't need to do extra IO at completion time, we can safely complete them inline from that. This patchset adds IOCB_DIO_CALLER_COMP, which an IO issuer can set to inform the completion side that any extra work that needs doing for that completion can be punted to a safe task context. The iomap dio completion will happen in hard/soft irq context, and we need a saner context to process these completions. IOCB_DIO_CALLER_COMP is added, which can be set in a struct kiocb->ki_flags by the issuer. If the completion side of the iocb handling understands this flag, it can choose to set a kiocb->dio_complete() handler and just call ki_complete from IRQ context. The issuer must then ensure that this callback is processed from a task. io_uring punts IRQ completions to task_work already, so it's trivial wire it up to run more of the completion before posting a CQE. This is good for up to a 37% improvement in throughput/latency for low queue depth IO, patch 5 has the details. If we need to do real work at completion time, iomap will clear the IOMAP_DIO_CALLER_COMP flag. This work came about when Andres tested low queue depth dio writes for postgres and compared it to doing sync dio writes, showing that the async processing slows us down a lot. * tag 'xfs-async-dio.6-2023-08-01' of git://git.kernel.dk/linux: iomap: support IOCB_DIO_CALLER_COMP io_uring/rw: add write support for IOCB_DIO_CALLER_COMP fs: add IOCB flags related to passing back dio completions iomap: add IOMAP_DIO_INLINE_COMP iomap: only set iocb->private for polled bio iomap: treat a write through cache the same as FUA iomap: use an unsigned type for IOMAP_DIO_* defines iomap: cleanup up iomap_dio_bio_end_io() Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-08-01iomap: support IOCB_DIO_CALLER_COMPJens Axboe
If IOCB_DIO_CALLER_COMP is set, utilize that to set kiocb->dio_complete handler and data for that callback. Rather than punt the completion to a workqueue, we pass back the handler and data to the issuer and will get a callback from a safe task context. Using the following fio job to randomly dio write 4k blocks at queue depths of 1..16: fio --name=dio-write --filename=/data1/file --time_based=1 \ --runtime=10 --bs=4096 --rw=randwrite --norandommap --buffered=0 \ --cpus_allowed=4 --ioengine=io_uring --iodepth=$depth shows the following results before and after this patch: Stock Patched Diff ======================================= QD1 155K 162K + 4.5% QD2 290K 313K + 7.9% QD4 533K 597K +12.0% QD8 604K 827K +36.9% QD16 615K 845K +37.4% which shows nice wins all around. If we factored in per-IOP efficiency, the wins look even nicer. This becomes apparent as queue depth rises, as the offloaded workqueue completions runs out of steam. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-08-01iomap: add IOMAP_DIO_INLINE_COMPJens Axboe
Rather than gate whether or not we need to punt a dio completion to a workqueue on whether the IO is a write or not, add an explicit flag for it. For now we treat them the same, reads always set the flags and async writes do not. No functional changes in this patch. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-08-01iomap: only set iocb->private for polled bioJens Axboe
iocb->private is only used for polled IO, where the completer will find the bio to poll through that field. Assign it when we're submitting a polled bio, and get rid of the dio->poll_bio indirection. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-08-01iomap: treat a write through cache the same as FUAJens Axboe
Whether we have a write back cache and are using FUA or don't have a write back cache at all is the same situation. Treat them the same. This makes the IOMAP_DIO_WRITE_FUA name a bit misleading, as we have two cases that provide stable writes: 1) Volatile write cache with FUA writes 2) Normal write without a volatile write cache Rename that flag to IOMAP_DIO_STABLE_WRITE to make that clearer, and update some of the FUA comments as well. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-08-01iomap: use an unsigned type for IOMAP_DIO_* definesJens Axboe
IOMAP_DIO_DIRTY shifts by 31 bits, which makes UBSAN unhappy. Clean up all the defines by making the shifted value an unsigned value. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reported-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-08-01iomap: cleanup up iomap_dio_bio_end_io()Jens Axboe
Make the logic a bit easier to follow: 1) Add a release_bio out path, as everybody needs to touch that, and have our bio ref check jump there if it's non-zero. 2) Add a kiocb local variable. 3) Add comments for each of the three conditions (sync, inline, or async workqueue punt). No functional changes in this patch. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-25iomap: Add per-block dirty state tracking to improve performanceRitesh Harjani (IBM)
When filesystem blocksize is less than folio size (either with mapping_large_folio_support() or with blocksize < pagesize) and when the folio is uptodate in pagecache, then even a byte write can cause an entire folio to be written to disk during writeback. This happens because we currently don't have a mechanism to track per-block dirty state within struct iomap_folio_state. We currently only track uptodate state. This patch implements support for tracking per-block dirty state in iomap_folio_state->state bitmap. This should help improve the filesystem write performance and help reduce write amplification. Performance testing of below fio workload reveals ~16x performance improvement using nvme with XFS (4k blocksize) on Power (64K pagesize) FIO reported write bw scores improved from around ~28 MBps to ~452 MBps. 1. <test_randwrite.fio> [global] ioengine=psync rw=randwrite overwrite=1 pre_read=1 direct=0 bs=4k size=1G dir=./ numjobs=8 fdatasync=1 runtime=60 iodepth=64 group_reporting=1 [fio-run] 2. Also our internal performance team reported that this patch improves their database workload performance by around ~83% (with XFS on Power) Reported-by: Aravinda Herle <araherle@in.ibm.com> Reported-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-25iomap: Allocate ifs in ->write_begin() earlyRitesh Harjani (IBM)
We dont need to allocate an ifs in ->write_begin() for writes where the position and length completely overlap with the given folio. Therefore, such cases are skipped. Currently when the folio is uptodate, we only allocate ifs at writeback time (in iomap_writepage_map()). This is ok until now, but when we are going to add support for per-block dirty state bitmap in ifs, this could cause some performance degradation. The reason is that if we don't allocate ifs during ->write_begin(), then we will never mark the necessary dirty bits in ->write_end() call. And we will have to mark all the bits as dirty at the writeback time, that could cause the same write amplification and performance problems as it is now. Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-07-25iomap: Refactor iomap_write_delalloc_punch() function outRitesh Harjani (IBM)
This patch factors iomap_write_delalloc_punch() function out. This function is resposible for actual punch out operation. The reason for doing this is, to avoid deep indentation when we bring punch-out of individual non-dirty blocks within a dirty folio in a later patch (which adds per-block dirty status handling to iomap) to avoid delalloc block leak. Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-07-25iomap: Use iomap_punch_t typedefRitesh Harjani (IBM)
It makes it much easier if we have iomap_punch_t typedef for "punch" function pointer in all delalloc related punch, scan and release functions. It will be useful in later patches when we will factor out iomap_write_delalloc_punch() function. Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-25iomap: Fix possible overflow condition in iomap_write_delalloc_scanRitesh Harjani (IBM)
folio_next_index() returns an unsigned long value which left shifted by PAGE_SHIFT could possibly cause an overflow on 32-bit system. Instead use folio_pos(folio) + folio_size(folio), which does this correctly. Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-25iomap: Add some uptodate state handling helpers for ifs state bitmapRitesh Harjani (IBM)
This patch adds two of the helper routines ifs_is_fully_uptodate() and ifs_block_is_uptodate() for managing uptodate state of "ifs" state bitmap. In later patches ifs state bitmap array will also handle dirty state of all blocks of a folio. Hence this patch adds some helper routines for handling uptodate state of the ifs state bitmap. Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-25iomap: Drop ifs argument from iomap_set_range_uptodate()Ritesh Harjani (IBM)
iomap_folio_state (ifs) can be derived directly from the folio, making it unnecessary to pass "ifs" as an argument to iomap_set_range_uptodate(). This patch eliminates "ifs" argument from iomap_set_range_uptodate() function. Also, the definition of iomap_set_range_uptodate() and ifs_set_range_uptodate() functions are moved above ifs_alloc(). In upcoming patches, we plan to introduce additional helper routines for handling dirty state, with the intention of consolidating all of "ifs" state handling routines at one place. Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-25iomap: Rename iomap_page to iomap_folio_state and othersRitesh Harjani (IBM)
struct iomap_page actually tracks per-block state of a folio. Hence it make sense to rename some of these function names and data structures for e.g. 1. struct iomap_page (iop) -> struct iomap_folio_state (ifs) 2. iomap_page_create() -> ifs_alloc() 3. iomap_page_release() -> ifs_free() 4. iomap_iop_set_range_uptodate() -> ifs_set_range_uptodate() 5. to_iomap_page() -> folio->private Since in later patches we are also going to add per-block dirty state tracking to iomap_folio_state. Hence this patch also renames "uptodate" & "uptodate_lock" members of iomap_folio_state to "state" and"state_lock". We don't really need to_iomap_page() function, instead directly open code it as folio->private; Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-24iomap: Copy larger chunks from userspaceMatthew Wilcox (Oracle)
If we have a large folio, we can copy in larger chunks than PAGE_SIZE. Start at the maximum page cache size and shrink by half every time we hit the "we are short on memory" problem. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-24iomap: Create large folios in the buffered write pathMatthew Wilcox (Oracle)
Use the size of the write as a hint for the size of the folio to create. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-24filemap: Add fgf_t typedefMatthew Wilcox (Oracle)
Similarly to gfp_t, define fgf_t as its own type to prevent various misuses and confusion. Leave the flags as FGP_* for now to reduce the size of this patch; they will be converted to FGF_* later. Move the documentation to the definition of the type insted of burying it in the __filemap_get_folio() documentation. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-07-24iomap: Remove unnecessary test from iomap_release_folio()Matthew Wilcox (Oracle)
The check for the folio being under writeback is unnecessary; the caller has checked this and the folio is locked, so the folio cannot be under writeback at this point. The comment is somewhat misleading in that it talks about one specific situation in which we can see a dirty folio. There are others, so change the comment to explain why we can't release the iomap_page. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2023-07-24iomap: Remove large folio handling in iomap_invalidate_folio()Matthew Wilcox (Oracle)
We do not need to release the iomap_page in iomap_invalidate_folio() to allow the folio to be split. The splitting code will call ->release_folio() if there is still per-fs private data attached to the folio. At that point, we will check if the folio is still dirty and decline to release the iomap_page. It is possible to trigger the warning in perfectly legitimate circumstances (eg if a disk read fails, we do a partial write to the folio, then we truncate the folio), which will cause those writes to be lost. Fixes: 60d8231089f0 ("iomap: Support large folios in invalidatepage") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-07-17iomap: micro optimize the ki_pos assignment in iomap_file_buffered_writeChristoph Hellwig
We have the new value for ki_pos right at hand in iter.pos, so assign that instead of recalculating it from ret. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Ritesh Harjani (IBM) <ritesh.harjani@gmail.com>