Changes in fsdev.c

0fc8f6200d2313278fbf4539bbab74677c685531 - Merge drm/drm-fixes into drm-misc-fixes

Mon, 27 Apr 2026 10:26:49 +0200

Merge drm/drm-fixes into drm-misc-fixesGetting fixes and updates from v7.1-rc1.Signed-off-by: Thomas Zimmermann List of files: /linux/drivers/dax/fsdev.c

bb0bc49a1cef574646eb25d74709c5ff200903a8 - Merge tag 'libnvdimm-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Tue, 21 Apr 2026 23:12:01 +0200

Merge tag 'libnvdimm-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimmPull dax updates from Ira Weiny: "The series adds DAX support required for the upcoming fuse/famfs file system.[1] The support here is required because famfs is backed by devdax rather than pmem. This all lays the groundwork for using shared memory as a file system"Link: https://lore.kernel.org/all/0100019d43e5f632-f5862a3e-361c-4b54-a9a6-96c242a8f17a-000000@email.amazonses.com/ [1]* tag 'libnvdimm-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax/fsdev: fix uninitialized kaddr in fsdev_dax_zero_page_range() dax: export dax_dev_get() dax: Add fs_dax_get() func to prepare dax for fs-dax usage dax: Add dax_set_ops() for setting dax_operations at bind time dax: Add dax_operations for use by fs-dax on fsdev dax dax: Save the kva from memremap dax: add fsdev.c driver for fs-dax on character dax dax: Factor out dax_folio_reset_order() helper dax: move dax_pgoff_to_phys from [drivers/dax/] device.c to bus.c List of files: /linux/drivers/dax/fsdev.c

45df9111692c62d5f09fc4345ae36dae31024797 - dax/fsdev: fix uninitialized kaddr in fsdev_dax_zero_page_range()

Sun, 12 Apr 2026 17:50:06 +0200

dax/fsdev: fix uninitialized kaddr in fsdev_dax_zero_page_range()__fsdev_dax_direct_access() returns -EFAULT without setting *kaddr whendax_pgoff_to_phys() returns -1 (pgoff out of range). The return valuewas ignored, leaving kaddr uninitialized before being passed tofsdev_write_dax().Check the return value and propagate the error.Thanks to Dan Carpenter and the smatch project for reporting this.Signed-off-by: John Groves Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Link: https://patch.msgid.link/0100019d8262cda2-9714d31c-8fc1-4ca5-b32d-4df678240d14-000000@email.amazonses.comSigned-off-by: Ira Weiny List of files: /linux/drivers/dax/fsdev.c

700ecbc1f5aa02ba9ad68d7be1ef7a9c8eae07e9 - dax: Add dax_set_ops() for setting dax_operations at bind time

Fri, 27 Mar 2026 22:05:03 +0100

dax: Add dax_set_ops() for setting dax_operations at bind timeAdd a new dax_set_ops() function that allows drivers to set thedax_operations after the dax_device has been allocated. This is neededfor fsdev_dax where the operations need to be set during probe andcleared during unbind.The fsdev driver uses devm_add_action_or_reset() for cleanup consistency,avoiding the complexity of mixing devm-managed resources with manualcleanup in a remove() callback. This ensures cleanup happens automaticallyin the correct reverse order when the device is unbound.Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Signed-off-by: John Groves Link: https://patch.msgid.link/0100019d311d65a0-b9c1419e-f3a0-4afd-b0bd-848f18ff5950-000000@email.amazonses.comSigned-off-by: Ira Weiny List of files: /linux/drivers/dax/fsdev.c

099c81a1f0ab3e948d73c5ab2b7a3b702af36e64 - dax: Add dax_operations for use by fs-dax on fsdev dax

Fri, 27 Mar 2026 22:04:54 +0100

dax: Add dax_operations for use by fs-dax on fsdev daxfsdev: Add dax_operations for use by famfs.This replicates the functionality from drivers/nvdimm/pmem.c thatconventional fs-dax file systems (e.g. xfs) use to support daxread/write/mmap to a daxdev - without which famfs can't sit atop adaxdev.- These methods are based on pmem_dax_ops from drivers/nvdimm/pmem.c- fsdev_dax_direct_access() returns the hpa, pfn and kva. The kva was newly stored as dev_dax->virt_addr by dev_dax_probe().- The hpa/pfn are used for mmap (dax_iomap_fault()), and the kva is used for read/write (dax_iomap_rw())- fsdev_dax_recovery_write() and dev_dax_zero_page_range() have not been tested yet. I'm looking for suggestions as to how to test those.- dax-private.h: add dev_dax->cached_size, which fsdev needs to remember. The dev_dax size cannot change while a driver is bound (dev_dax_resize returns -EBUSY if dev->driver is set). Caching the size at probe time allows fsdev's direct_access path can use it without acquiring dax_dev_rwsem (which isn't exported anyway).Signed-off-by: John Groves Link: https://patch.msgid.link/0100019d311d415a-bd6af0fe-5445-484c-9d39-210b8170b686-000000@email.amazonses.comSigned-off-by: Ira Weiny List of files: /linux/drivers/dax/fsdev.c

759455848df0b9ac3acabdbedcdc4a55af67935f - dax: Save the kva from memremap

Fri, 27 Mar 2026 22:04:44 +0100

dax: Save the kva from memremapSave the kva from memremap because we need it for iomap rw support.Prior to famfs, there were no iomap users of /dev/dax - so the virtualaddress from memremap was not needed.Reviewed-by: Ira Weiny Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Signed-off-by: John Groves Link: https://patch.msgid.link/0100019d311d1d08-dd372cb9-5934-43b8-bef8-089660d04a81-000000@email.amazonses.comSigned-off-by: Ira Weiny List of files: /linux/drivers/dax/fsdev.c

d5406bd458b0ac10b1301a4d5801d85c8f648637 - dax: add fsdev.c driver for fs-dax on character dax

Fri, 27 Mar 2026 22:04:35 +0100

dax: add fsdev.c driver for fs-dax on character daxThe new fsdev driver provides pages/folios initialized compatibly withfsdax - normal rather than devdax-style refcounting, and starting outwith order-0 folios.When fsdev binds to a daxdev, it is usually (always?) switching from thedevdax mode (device.c), which pre-initializes compound folios accordingto its alignment. Fsdev uses fsdev_clear_folio_state() to switch thefolios into a fsdax-compatible state.A side effect of this is that raw mmap doesn't (can't?) work on an fsdevdax instance. Accordingly, The fsdev driver does not provide raw mmap -devices must be put in 'devdax' mode (drivers/dax/device.c) to get rawmmap capability.In this commit is just the framework, which remaps pages/folios compatiblywith fsdax.Enabling dax changes:- bus.h: add DAXDRV_FSDEV_TYPE driver type- bus.c: allow DAXDRV_FSDEV_TYPE drivers to bind to daxdevs- dax.h: prototype inode_dax(), which fsdev needsSuggested-by: Dan Williams Suggested-by: Gregory Price Reviewed-by: Jonathan Cameron Signed-off-by: John Groves Link: https://patch.msgid.link/0100019d311cf904-419e9526-bdaf-4daa-97f1-5060b31a5c9f-000000@email.amazonses.comSigned-off-by: Ira Weiny List of files: /linux/drivers/dax/fsdev.c