linux/kernel/dma, branch v6.3

swiotlb: fix a braino in the alignment check fix

2023-04-06T14:45:12Z

The alignment mask in swiotlb_do_find_slots() masks off the high bits which are not relevant for the alignment, so multiple requirements are combined with a bitwise OR rather than AND. In plain English, the stricter the alignment, the more bits must be set in iotlb_align_mask. Confusion may arise from the fact that the same variable is also used to mask off the offset within a swiotlb slot, which is achieved with a bitwise AND. Fixes: 0eee5ae10256 ("swiotlb: fix slot alignment checks") Reported-by: Dexuan Cui Link: https://lore.kernel.org/all/CAA42JLa1y9jJ7BgQvXeUYQh-K2mDNHd2BYZ4iZUz33r5zY7oAQ@mail.gmail.com/ Reported-by: Kelsey Steele Link: https://lore.kernel.org/all/20230405003549.GA21326@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/ Signed-off-by: Petr Tesarik Tested-by: Dexuan Cui Signed-off-by: Christoph Hellwig

swiotlb: fix slot alignment checks

2023-03-22T08:03:17Z

Explicit alignment and page alignment are used only to calculate the stride, not when checking actual slot physical address. Originally, only page alignment was implemented, and that worked, because the whole SWIOTLB is allocated on a page boundary, so aligning the start index was sufficient to ensure a page-aligned slot. When commit 1f221a0d0dbf ("swiotlb: respect min_align_mask") added support for min_align_mask, the index could be incremented in the search loop, potentially finding an unaligned slot if minimum device alignment is between IO_TLB_SIZE and PAGE_SIZE. The bug could go unnoticed, because the slot size is 2 KiB, and the most common page size is 4 KiB, so there is no alignment value in between. IIUC the intention has been to find a slot that conforms to all alignment constraints: device minimum alignment, an explicit alignment (given as function parameter) and optionally page alignment (if allocation size is >= PAGE_SIZE). The most restrictive mask can be trivially computed with logical AND. The rest can stay. Fixes: 1f221a0d0dbf ("swiotlb: respect min_align_mask") Fixes: e81e99bacc9f ("swiotlb: Support aligned swiotlb buffers") Signed-off-by: Petr Tesarik Signed-off-by: Christoph Hellwig

swiotlb: use wrap_area_index() instead of open-coding it

2023-03-22T08:02:35Z

No functional change, just use an existing helper. Signed-off-by: Petr Tesarik Signed-off-by: Christoph Hellwig

swiotlb: fix the deadlock in swiotlb_do_find_slots

2023-03-15T14:47:40Z

In general, if swiotlb is sufficient, the logic of index = wrap_area_index(mem, index + 1) is fine, it will quickly take a slot and release the area->lock; But if swiotlb is insufficient and the device has min_align_mask requirements, such as NVME, we may not be able to satisfy index == wrap and exit the loop properly. In this case, other kernel threads will not be able to acquire the area->lock and release the slot, resulting in a deadlock. The current implementation of wrap_area_index does not involve a modulo operation, so adjusting the wrap to ensure the loop ends is not trivial. Introduce a new variable to record the number of loops and exit the loop after completing the traversal. Backtraces: Other CPUs are waiting this core to exit the swiotlb_do_find_slots loop. [10199.924391] RIP: 0010:swiotlb_do_find_slots+0x1fe/0x3e0 [10199.924403] Call Trace: [10199.924404] [10199.924405] swiotlb_tbl_map_single+0xec/0x1f0 [10199.924407] swiotlb_map+0x5c/0x260 [10199.924409] ? nvme_pci_setup_prps+0x1ed/0x340 [10199.924411] dma_direct_map_page+0x12e/0x1c0 [10199.924413] nvme_map_data+0x304/0x370 [10199.924415] nvme_prep_rq.part.0+0x31/0x120 [10199.924417] nvme_queue_rq+0x77/0x1f0 ... [ 9639.596311] NMI backtrace for cpu 48 [ 9639.596336] Call Trace: [ 9639.596337] [ 9639.596338] _raw_spin_lock_irqsave+0x37/0x40 [ 9639.596341] swiotlb_do_find_slots+0xef/0x3e0 [ 9639.596344] swiotlb_tbl_map_single+0xec/0x1f0 [ 9639.596347] swiotlb_map+0x5c/0x260 [ 9639.596349] dma_direct_map_sg+0x7a/0x280 [ 9639.596352] __dma_map_sg_attrs+0x30/0x70 [ 9639.596355] dma_map_sgtable+0x1d/0x30 [ 9639.596356] nvme_map_data+0xce/0x370 ... [ 9639.595665] NMI backtrace for cpu 50 [ 9639.595682] Call Trace: [ 9639.595682] [ 9639.595683] _raw_spin_lock_irqsave+0x37/0x40 [ 9639.595686] swiotlb_release_slots.isra.0+0x86/0x180 [ 9639.595688] dma_direct_unmap_sg+0xcf/0x1a0 [ 9639.595690] nvme_unmap_data.part.0+0x43/0xc0 Fixes: 1f221a0d0dbf ("swiotlb: respect min_align_mask") Signed-off-by: GuoRui.Yu Signed-off-by: Xiaokang Hu Signed-off-by: Christoph Hellwig

swiotlb: mark swiotlb_memblock_alloc() as __init

2023-02-22T14:44:48Z

swiotlb_memblock_alloc() calls memblock_alloc(), which calls (__init) memblock_alloc_try_nid(). However, swiotlb_membloc_alloc() can be marked as __init since it is only called by swiotlb_init_remap(), which is already marked as __init. This prevents a modpost build warning/error: WARNING: modpost: vmlinux.o: section mismatch in reference: swiotlb_memblock_alloc (section: .text) -> memblock_alloc_try_nid (section: .init.text) WARNING: modpost: vmlinux.o: section mismatch in reference: swiotlb_memblock_alloc (section: .text) -> memblock_alloc_try_nid (section: .init.text) This fixes the build warning/error seen on ARM64, PPC64, S390, i386, and x86_64. Fixes: 8d58aa484920 ("swiotlb: reduce the swiotlb buffer size on allocation failure") Signed-off-by: Randy Dunlap Cc: Alexey Kardashevskiy Cc: Christoph Hellwig Cc: iommu@lists.linux.dev Cc: Mike Rapoport Cc: linux-mm@kvack.org Signed-off-by: Christoph Hellwig

swiotlb: remove swiotlb_max_segment

2023-02-16T17:10:18Z

swiotlb_max_segment has always been a bogus API, so remove it now that the remaining callers are gone. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-mapping: reject GFP_COMP for noncoherent allocations

2022-12-21T07:45:38Z

While not quite as bogus as for the dma-coherent allocations that were fixed earlier, GFP_COMP for these allocations has no benefits for the dma-direct case, and can't be supported at all by dma dma-iommu backend which splits up allocations into smaller orders. Due to an oversight in ffcb75458460 that flag stopped being cleared for all dma allocations, but only got rejected for coherent ones, so fix up these callers to not allow __GFP_COMP as well after the sound code has been fixed to not ask for it. Fixes: ffcb75458460 ("dma-mapping: reject __GFP_COMP in dma_alloc_attrs") Reported-by: Mikhail Gavrilov Reported-by: Kai Vehmanen Signed-off-by: Christoph Hellwig Acked-by: Takashi Iwai Tested-by: Mikhail Gavrilov Tested-by: Kai Vehmanen

dma-mapping: reject __GFP_COMP in dma_alloc_attrs

2022-11-21T08:37:20Z

DMA allocations can never be turned back into a page pointer, so requesting compound pages doesn't make sense and it can't even be supported at all by various backends. Reject __GFP_COMP with a warning in dma_alloc_attrs, and stop clearing the flag in the arm dma ops and dma-iommu. Signed-off-by: Christoph Hellwig Acked-by: Marek Szyprowski

swiotlb: reduce the swiotlb buffer size on allocation failure

2022-11-01T11:06:12Z

At the moment the AMD encrypted platform reserves 6% of RAM for SWIOTLB or 1GB, whichever is less. However it is possible that there is no block big enough in the low memory which make SWIOTLB allocation fail and the kernel continues without DMA. In such case a VM hangs on DMA. This moves alloc+remap to a helper and calls it from a loop where the size is halved on each iteration. This updates default_nslabs on successful allocation which looks like an oversight as not doing so should have broken callers of swiotlb_size_or_default(). Signed-off-by: Alexey Kardashevskiy Reviewed-by: Pankaj Gupta Signed-off-by: Christoph Hellwig

Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-11T00:53:04Z

Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...