talos-obmc-linux/kernel/memremap.c, branch v4.18.19

mm, dev_pagemap: Do not clear ->mapping on final put

2018-09-09T08:32:41+00:00

commit 2fa147bdbf672c53386a8f5f2c7fe358004c3ef8 upstream. MEMORY_DEVICE_FS_DAX relies on typical page semantics whereby ->mapping is only ever cleared by truncation, not final put. Without this fix dax pages may forget their mapping association at the end of every page pin event. Move this atypical behavior that HMM wants into the HMM ->page_free() callback. Cc: Cc: Jan Kara Cc: Jérôme Glisse Cc: Andrew Morton Cc: Ross Zwisler Fixes: d2c997c0f145 ("fs, dax: use page->mapping...") Signed-off-by: Dan Williams Acked-by: Jérôme Glisse Signed-off-by: Dave Jiang Signed-off-by: Greg Kroah-Hartman

mm: fix exports that inadvertently make put_page() EXPORT_SYMBOL_GPL

2018-07-27T02:38:03+00:00

Commit e76384884344 ("mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS") added two EXPORT_SYMBOL_GPL() symbols, but these symbols are required by the inlined put_page(), thus accidentally making put_page() a GPL export only. This breaks OpenAFS (at least). Mark them EXPORT_SYMBOL() instead. Link: http://lkml.kernel.org/r/153128611970.2928.11310692420711601254.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: e76384884344 ("mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS") Signed-off-by: Dan Williams Reported-by: Joe Gorse Reported-by: John Hubbard Tested-by: Joe Gorse Tested-by: John Hubbard Cc: Jérôme Glisse Cc: Mark Vitale Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: disallow mappings that conflict for devm_memremap_pages()

2018-07-27T02:38:03+00:00

When pmem namespaces created are smaller than section size, this can cause an issue during removal and gpf was observed: general protection fault: 0000 1 SMP PTI CPU: 36 PID: 3941 Comm: ndctl Tainted: G W 4.14.28-1.el7uek.x86_64 #2 task: ffff88acda150000 task.stack: ffffc900233a4000 RIP: 0010:__put_page+0x56/0x79 Call Trace: devm_memremap_pages_release+0x155/0x23a release_nodes+0x21e/0x260 devres_release_all+0x3c/0x48 device_release_driver_internal+0x15c/0x207 device_release_driver+0x12/0x14 unbind_store+0xba/0xd8 drv_attr_store+0x27/0x31 sysfs_kf_write+0x3f/0x46 kernfs_fop_write+0x10f/0x18b __vfs_write+0x3a/0x16d vfs_write+0xb2/0x1a1 SyS_write+0x55/0xb9 do_syscall_64+0x79/0x1ae entry_SYSCALL_64_after_hwframe+0x3d/0x0 Add code to check whether we have a mapping already in the same section and prevent additional mappings from being created if that is the case. Link: http://lkml.kernel.org/r/152909478401.50143.312364396244072931.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang Cc: Dan Williams Cc: Robert Elliott Cc: Jeff Moyer Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS

2018-05-22T13:59:39+00:00

In preparation for fixing dax-dma-vs-unmap issues, filesystems need to be able to rely on the fact that they will get wakeups on dev_pagemap page-idle events. Introduce MEMORY_DEVICE_FS_DAX and generic_dax_page_free() as common indicator / infrastructure for dax filesytems to require. With this change there are no users of the MEMORY_DEVICE_HOST designation, so remove it. The HMM sub-system extended dev_pagemap to arrange a callback when a dev_pagemap managed page is freed. Since a dev_pagemap page is free / idle when its reference count is 1 it requires an additional branch to check the page-type at put_page() time. Given put_page() is a hot-path we do not want to incur that check if HMM is not in use, so a static branch is used to avoid that overhead when not necessary. Now, the FS_DAX implementation wants to reuse this mechanism for receiving dev_pagemap ->page_free() callbacks. Rework the HMM-specific static-key into a generic mechanism that either HMM or FS_DAX code paths can enable. For ARCH=um builds, and any other arch that lacks ZONE_DEVICE support, care must be taken to compile out the DEV_PAGEMAP_OPS infrastructure. However, we still need to support FS_DAX in the FS_DAX_LIMITED case implemented by the s390/dcssblk driver. Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Michal Hocko Reported-by: kbuild test robot Reported-by: Thomas Meyer Reported-by: Dave Jiang Cc: "Jérôme Glisse" Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Signed-off-by: Dan Williams

memremap: split devm_memremap_pages() and memremap() infrastructure

2018-05-16T06:08:33+00:00

Currently, kernel/memremap.c contains generic code for supporting memremap() (CONFIG_HAS_IOMEM) and devm_memremap_pages() (CONFIG_ZONE_DEVICE). This causes ongoing build maintenance problems as additions to memremap.c, especially for the ZONE_DEVICE case, need to be careful about being placed in ifdef guards. Remove the need for these ifdef guards by moving the ZONE_DEVICE support functions to their own compilation unit. Cc: "Jérôme Glisse" Cc: Ross Zwisler Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Dan Williams

kernel/memremap: Remove stale devres_free() call

2018-03-06T18:58:54+00:00

devm_memremap_pages() was re-worked in e8d513483300 "memremap: change devm_memremap_pages interface to use struct dev_pagemap" to take a caller allocated struct dev_pagemap as a function parameter. A call to devres_free() was left in the error cleanup path which results in a kernel panic if the remap fails for some reason. Remove it to fix the panic and let devm_memremap_pages() fail gracefully. Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...") Signed-off-by: Oliver O'Halloran Reviewed-by: Christoph Hellwig Reviewed-by: Logan Gunthorpe Signed-off-by: Dan Williams

memremap: fix softlockup reports at teardown

2018-03-03T03:34:50+00:00

The cond_resched() currently in the setup path needs to be duplicated in the teardown path. Rather than require each instance of for_each_device_pfn() to open code the same sequence, embed it in the helper. Link: https://github.com/intel/ixpdimm_sw/issues/11 Cc: "Jérôme Glisse" Cc: Michal Hocko Cc: Christoph Hellwig Cc: Fixes: 71389703839e ("mm, zone_device: Replace {get, put}_zone_device_page()...") Signed-off-by: Dan Williams

mm: Fix devm_memremap_pages() collision handling

2018-01-20T00:29:56+00:00

If devm_memremap_pages() detects a collision while adding entries to the radix-tree, we call pgmap_radix_release(). Unfortunately, the function removes *all* entries for the range -- including the entries that caused the collision in the first place. Modify pgmap_radix_release() to take an additional argument to indicate where to stop, so that only newly added entries are removed from the tree. Cc: Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()") Signed-off-by: Jan H. Schönherr Signed-off-by: Dan Williams

mm: Fix memory size alignment in devm_memremap_pages_release()

2018-01-20T00:29:48+00:00

The functions devm_memremap_pages() and devm_memremap_pages_release() use different ways to calculate the section-aligned amount of memory. The latter function may use an incorrect size if the memory region is small but straddles a section border. Use the same code for both. Cc: Fixes: 5f29a77cd957 ("mm: fix mixed zone detection in devm_memremap_pages") Signed-off-by: Jan H. Schönherr Signed-off-by: Dan Williams

memremap: merge find_dev_pagemap into get_dev_pagemap

2018-01-08T19:46:23+00:00

There is only one caller of the trivial function find_dev_pagemap left, so just merge it into the caller. Signed-off-by: Christoph Hellwig Signed-off-by: Dan Williams