user/sven/linux.git/kernel/dma/debug.c, branch v5.9.8

dma-debug: remove debug_dma_assert_idle() function

2020-08-14T22:22:43Z

This remoes the code from the COW path to call debug_dma_assert_idle(), which was added many years ago. Google shows that it hasn't caught anything in the 6+ years we've had it apart from a false positive, and Hugh just noticed how it had a very unfortunate spinlock serialization in the COW path. He fixed that issue the previous commit (a85ffd59bd36: "dma-debug: fix debug_dma_assert_idle(), use rcu_read_lock()"), but let's see if anybody even notices when we remove this function entirely. NOTE! We keep the dma tracking infrastructure that was added by the commit that introduced it. Partly to make it easier to resurrect this debug code if we ever deside to, and partly because that tracking by pfn and offset looks quite reasonable. The problem with this debug code was simply that it was expensive and didn't seem worth it, not that it was wrong per se. Acked-by: Dan Williams Acked-by: Christoph Hellwig Signed-off-by: Linus Torvalds

dma-debug: fix debug_dma_assert_idle(), use rcu_read_lock()

2020-08-14T22:16:03Z

Since commit 2a9127fcf229 ("mm: rewrite wait_on_page_bit_common() logic") improved unlock_page(), it has become more noticeable how cow_user_page() in a kernel with CONFIG_DMA_API_DEBUG=y can create and suffer from heavy contention on DMA debug's radix_lock in debug_dma_assert_idle(). It is only doing a lookup: use rcu_read_lock() and rcu_read_unlock() instead; though that does require the static ents[] to be moved onstack... ...but, hold on, isn't that radix_tree_gang_lookup() and loop doing quite the wrong thing: searching CACHELINES_PER_PAGE entries for an exact match with the first cacheline of the page in question? radix_tree_gang_lookup() is the right tool for the job, but we need nothing more than to check the first entry it can find, reporting if that falls anywhere within the page. (Is RCU safe here? As safe as using the spinlock was. The entries are never freed, so don't need to be freed by RCU. They may be reused, and there is a faint chance of a race, with an offending entry reused while printing its error info; but the spinlock did not prevent that either, and I agree that it's not worth worrying about. ] [ Side noe: this patch is a clear improvement to the status quo, but the next patch will be removing this debug function entirely. But just in case we decide we want to resurrect the debugging code some day, I'm first applying this improvement patch so that it doesn't get lost - Linus ] Fixes: 3b7a6418c749 ("dma debug: account for cachelines and read-only mappings in overlap tracking") Signed-off-by: Hugh Dickins Acked-by: Dan Williams Acked-by: Christoph Hellwig Signed-off-by: Linus Torvalds

Merge tag 'docs-5.9' of git://git.lwn.net/linux

2020-08-05T05:47:54Z

Pull documentation updates from Jonathan Corbet: "It's been a busy cycle for documentation - hopefully the busiest for a while to come. Changes include: - Some new Chinese translations - Progress on the battle against double words words and non-HTTPS URLs - Some block-mq documentation - More RST conversions from Mauro. At this point, that task is essentially complete, so we shouldn't see this kind of churn again for a while. Unless we decide to switch to asciidoc or something...:) - Lots of typo fixes, warning fixes, and more" * tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits) scripts/kernel-doc: optionally treat warnings as errors docs: ia64: correct typo mailmap: add entry for doc/zh_CN: add cpu-load Chinese version Documentation/admin-guide: tainted-kernels: fix spelling mistake MAINTAINERS: adjust kprobes.rst entry to new location devices.txt: document rfkill allocation PCI: correct flag name docs: filesystems: vfs: correct flag name docs: filesystems: vfs: correct sync_mode flag names docs: path-lookup: markup fixes for emphasis docs: path-lookup: more markup fixes docs: path-lookup: fix HTML entity mojibake CREDITS: Replace HTTP links with HTTPS ones docs: process: Add an example for creating a fixes tag doc/zh_CN: add Chinese translation prefer section doc/zh_CN: add clearing-warn-once Chinese version doc/zh_CN: add admin-guide index doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label futex: MAINTAINERS: Re-add selftests directory ...

Merge tag 'dma-mapping-5.9' of git://git.infradead.org/users/hch/dma-mapping

2020-08-05T00:29:57Z

Pull dma-mapping updates from Christoph Hellwig: - make support for dma_ops optional - move more code out of line - add generic support for a dma_ops bypass mode - misc cleanups * tag 'dma-mapping-5.9' of git://git.infradead.org/users/hch/dma-mapping: dma-contiguous: cleanup dma_alloc_contiguous dma-debug: use named initializers for dir2name powerpc: use the generic dma_ops_bypass mode dma-mapping: add a dma_ops_bypass flag to struct device dma-mapping: make support for dma ops optional dma-mapping: inline the fast path dma-direct calls dma-mapping: move the remaining DMA API calls out of line

dma-debug: use named initializers for dir2name

2020-07-19T07:31:13Z

Make dir2name a little more readable and maintainable by using named initializers. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

treewide: Remove uninitialized_var() usage

2020-07-16T19:35:15Z

Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var$([^$]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe # IB Acked-by: Kalle Valo # wireless drivers Reviewed-by: Chao Yu # erofs Signed-off-by: Kees Cook

docs: fix references for DMA*.txt files

2020-06-26T16:01:32Z

As we moved those files to core-api, fix references to point to their newer locations. Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/37b2fd159fbc7655dbf33b3eb1215396a25f6344.1592895969.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet

dma-debug: make __dma_entry_alloc_check_leak() static

2020-04-20T10:05:18Z

Fix the following sparse warning: kernel/dma/debug.c:659:6: warning: symbol '__dma_entry_alloc_check_leak' was not declared. Should it be static? Reported-by: Hulk Robot Signed-off-by: Jason Yan Signed-off-by: Christoph Hellwig

dma-debug: fix displaying of dma allocation type

2020-04-08T19:46:57Z

The commit 2e05ea5cdc1a ("dma-mapping: implement dma_map_single_attrs using dma_map_page_attrs") removed "dma_debug_page" enum, but missed to update type2name string table. This causes incorrect displaying of dma allocation type. Fix it by removing "page" string from type2name string table and switch to use named initializers. Before (dma_alloc_coherent()): k3-ringacc 4b800000.ringacc: scather-gather idx 2208 P=d1140000 N=d114 D=d1140000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable k3-ringacc 4b800000.ringacc: scather-gather idx 2216 P=d1150000 N=d115 D=d1150000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable After: k3-ringacc 4b800000.ringacc: coherent idx 2208 P=d1140000 N=d114 D=d1140000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable k3-ringacc 4b800000.ringacc: coherent idx 2216 P=d1150000 N=d115 D=d1150000 L=40 DMA_BIDIRECTIONAL dma map error check not applicable Fixes: 2e05ea5cdc1a ("dma-mapping: implement dma_map_single_attrs using dma_map_page_attrs") Signed-off-by: Grygorii Strashko Signed-off-by: Christoph Hellwig

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux; tag 'dma-mapping-5.5' of git://git.infradead.org/users/hch/dma-mapping

2019-11-28T19:16:43Z

Pull dma-mapping updates from Christoph Hellwig: - improve dma-debug scalability (Eric Dumazet) - tiny dma-debug cleanup (Dan Carpenter) - check for vmap memory in dma_map_single (Kees Cook) - check for dma_addr_t overflows in dma-direct when using DMA offsets (Nicolas Saenz Julienne) - switch the x86 sta2x11 SOC to use more generic DMA code (Nicolas Saenz Julienne) - fix arm-nommu dma-ranges handling (Vladimir Murzin) - use __initdata in CMA (Shyam Saini) - replace the bus dma mask with a limit (Nicolas Saenz Julienne) - merge the remapping helpers into the main dma-direct flow (me) - switch xtensa to the generic dma remap handling (me) - various cleanups around dma_capable (me) - remove unused dev arguments to various dma-noncoherent helpers (me) * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux: * tag 'dma-mapping-5.5' of git://git.infradead.org/users/hch/dma-mapping: (22 commits) dma-mapping: treat dev->bus_dma_mask as a DMA limit dma-direct: exclude dma_direct_map_resource from the min_low_pfn check dma-direct: don't check swiotlb=force in dma_direct_map_resource dma-debug: clean up put_hash_bucket() powerpc: remove support for NULL dev in __phys_to_dma / __dma_to_phys dma-direct: avoid a forward declaration for phys_to_dma dma-direct: unify the dma_capable definitions dma-mapping: drop the dev argument to arch_sync_dma_for_* x86/PCI: sta2x11: use default DMA address translation dma-direct: check for overflows on 32 bit DMA addresses dma-debug: increase HASH_SIZE dma-debug: reorder struct dma_debug_entry fields xtensa: use the generic uncached segment support dma-mapping: merge the generic remapping helpers into dma-direct dma-direct: provide mmap and get_sgtable method overrides dma-direct: remove the dma_handle argument to __dma_direct_alloc_pages dma-direct: remove __dma_direct_free_pages usb: core: Remove redundant vmap checks kernel: dma-contiguous: mark CMA parameters __initdata/__initconst dma-debug: add a schedule point in debug_dma_dump_mappings() ...