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2017-03-11device-dax: fix debug output typoDave Jiang1-3/+3
The debug output for return the return data of pgoff_to_phys() in the fault handlers has 'phys' and 'pgoff' incorrectly swapped. Reported-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-03-11device-dax: fix pud fault fallback handlingDave Jiang1-0/+12
Jeff Moyer reports: With a device dax alignment of 4KB or 2MB, I get sigbus when running the attached fio job file for the current kernel (4.11.0-rc1+). If I specify an alignment of 1GB, it works. I turned on debug output, and saw that it was failing in the huge fault code. dax dax1.0: dax_open dax dax1.0: dax_mmap dax dax1.0: dax_dev_huge_fault: fio: write (0x7f08f0a00000 - dax dax1.0: __dax_dev_pud_fault: phys_to_pgoff(0xffffffffcf60) dax dax1.0: dax_release fio config for reproduce: [global] ioengine=dev-dax direct=0 filename=/dev/dax0.0 bs=2m [write] rw=write [read] stonewall rw=read The driver fails to fallback when taking a fault that is larger than the device alignment, or handling a larger fault when a smaller mapping is already established. While we could support larger mappings for a device with a smaller alignment, that change is too large for the immediate fix. The simplest change is to force fallback until the fault size matches the alignment. Reported-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-03-11device-dax: fix pmd/pte fault fallback handlingDave Jiang1-0/+15
Jeff Moyer reports: With a device dax alignment of 4KB or 2MB, I get sigbus when running the attached fio job file for the current kernel (4.11.0-rc1+). If I specify an alignment of 1GB, it works. I turned on debug output, and saw that it was failing in the huge fault code. dax dax1.0: dax_open dax dax1.0: dax_mmap dax dax1.0: dax_dev_huge_fault: fio: write (0x7f08f0a00000 - dax dax1.0: __dax_dev_pud_fault: phys_to_pgoff(0xffffffffcf60 dax dax1.0: dax_release fio config for reproduce: [global] ioengine=dev-dax direct=0 filename=/dev/dax0.0 bs=2m [write] rw=write [read] stonewall rw=read The driver fails to fallback when taking a fault that is larger than the device alignment, or handling a larger fault when a smaller mapping is already established. While we could support larger mappings for a device with a smaller alignment, that change is too large for the immediate fix. The simplest change is to force fallback until the fault size matches the alignment. Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Cc: <stable@vger.kernel.org> Reported-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-03-02sched/headers: Prepare to remove the <linux/magic.h> include from ↵Ingo Molnar1-0/+1
<linux/sched/task_stack.h> Update files that depend on the magic.h inclusion. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-25mm: replace FAULT_FLAG_SIZE with parameter to huge_faultDave Jiang1-6/+12
Since the introduction of FAULT_FLAG_SIZE to the vm_fault flag, it has been somewhat painful with getting the flags set and removed at the correct locations. More than one kernel oops was introduced due to difficulties of getting the placement correctly. Remove the flag values and introduce an input parameter to huge_fault that indicates the size of the page entry. This makes the code easier to trace and should avoid the issues we see with the fault flags where removal of the flag was necessary in the fallback paths. Link: http://lkml.kernel.org/r/148615748258.43180.1690152053774975329.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25dax: support for transparent PUD pages for device DAXDave Jiang1-0/+48
Add transparent huge PUD pages support for device DAX by adding a pud_fault handler. Link: http://lkml.kernel.org/r/148545060002.17912.6765687780007547551.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25mm,fs,dax: change ->pmd_fault to ->huge_faultDave Jiang1-21/+13
Patch series "1G transparent hugepage support for device dax", v2. The following series implements support for 1G trasparent hugepage on x86 for device dax. The bulk of the code was written by Mathew Wilcox a while back supporting transparent 1G hugepage for fs DAX. I have forward ported the relevant bits to 4.10-rc. The current submission has only the necessary code to support device DAX. Comments from Dan Williams: So the motivation and intended user of this functionality mirrors the motivation and users of 1GB page support in hugetlbfs. Given expected capacities of persistent memory devices an in-memory database may want to reduce tlb pressure beyond what they can already achieve with 2MB mappings of a device-dax file. We have customer feedback to that effect as Willy mentioned in his previous version of these patches [1]. [1]: https://lkml.org/lkml/2016/1/31/52 Comments from Nilesh @ Oracle: There are applications which have a process model; and if you assume 10,000 processes attempting to mmap all the 6TB memory available on a server; we are looking at the following: processes : 10,000 memory : 6TB pte @ 4k page size: 8 bytes / 4K of memory * #processes = 6TB / 4k * 8 * 10000 = 1.5GB * 80000 = 120,000GB pmd @ 2M page size: 120,000 / 512 = ~240GB pud @ 1G page size: 240GB / 512 = ~480MB As you can see with 2M pages, this system will use up an exorbitant amount of DRAM to hold the page tables; but the 1G pages finally brings it down to a reasonable level. Memory sizes will keep increasing; so this number will keep increasing. An argument can be made to convert the applications from process model to thread model, but in the real world that may not be always practical. Hopefully this helps explain the use case where this is valuable. This patch (of 3): In preparation for adding the ability to handle PUD pages, convert vm_operations_struct.pmd_fault to vm_operations_struct.huge_fault. The vm_fault structure is extended to include a union of the different page table pointers that may be needed, and three flag bits are reserved to indicate which type of pointer is in the union. [ross.zwisler@linux.intel.com: remove unused function ext4_dax_huge_fault()] Link: http://lkml.kernel.org/r/1485813172-7284-1-git-send-email-ross.zwisler@linux.intel.com [dave.jiang@intel.com: clear PMD or PUD size flags when in fall through path] Link: http://lkml.kernel.org/r/148589842696.5820.16078080610311444794.stgit@djiang5-desk3.ch.intel.com Link: http://lkml.kernel.org/r/148545058784.17912.6353162518188733642.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-25mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmfDave Jiang1-6/+6
->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to take a vma and vmf parameter when the vma already resides in vmf. Remove the vma parameter to simplify things. [arnd@arndb.de: fix ARM build] Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-23mm, dax: change pmd_fault() to take only vmf parameterDave Jiang1-9/+9
pmd_fault() and related functions really only need the vmf parameter since the additional parameters are all included in the vmf struct. Remove the additional parameter and simplify pmd_fault() and friends. Link: http://lkml.kernel.org/r/1484085142-2297-8-git-send-email-ross.zwisler@linux.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-23mm, dax: make pmd_fault() and friends be the same as fault()Dave Jiang1-9/+7
Instead of passing in multiple parameters in the pmd_fault() handler, a vmf can be passed in just like a fault() handler. This will simplify code and remove the need for the actual pmd fault handlers to allocate a vmf. Related functions are also modified to do the same. [dave.jiang@intel.com: fix issue with xfs_tests stall when DAX option is off] Link: http://lkml.kernel.org/r/148469861071.195597.3619476895250028518.stgit@djiang5-desk3.ch.intel.com Link: http://lkml.kernel.org/r/1484085142-2297-7-git-send-email-ross.zwisler@linux.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-19Merge tag 'libnvdimm-for-4.10' of ↵Linus Torvalds2-1/+96
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm Pull libnvdimm updates from Dan Williams: "The libnvdimm pull request is relatively small this time around due to some development topics being deferred to 4.11. As for this pull request the bulk of it has been in -next for several releases leading to one late fix being added (commit 868f036fee4b ("libnvdimm: fix mishandled nvdimm_clear_poison() return value")). It has received a build success notification from the 0day-kbuild robot and passes the latest libnvdimm unit tests. Summary: - Dynamic label support: To date namespace label support has been limited to disambiguating cases where PMEM (direct load/store) and BLK (mmio aperture) accessed-capacity alias on the same DIMM. Since 4.9 added support for multiple namespaces per PMEM-region there is value to support namespace labels even in the non-aliasing case. The presence of a valid namespace index block force-enables label support when the kernel would otherwise rely on region boundaries, and permits the region to be sub-divided. - Handle media errors in namespace metadata: Complement the error handling for media errors in namespace data areas with support for clearing errors on writes, and downgrading potential machine-check exceptions to simple i/o errors on read. - Device-DAX region attributes: Add 'align', 'id', and 'size' as attributes for device-dax regions. In particular this enables userspace tooling to generically size memory mapping and i/o operations. Prevent userspace from growing assumptions / dependencies about the parent device topology for a dax region. A libnvdimm namespace may not always be the parent device of a dax region. - Various cleanups and small fixes" * tag 'libnvdimm-for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax: add region 'id', 'size', and 'align' attributes libnvdimm: fix mishandled nvdimm_clear_poison() return value libnvdimm: replace mutex_is_locked() warnings with lockdep_assert_held libnvdimm, pfn: fix align attribute libnvdimm, e820: use module_platform_driver libnvdimm, namespace: use octal for permissions libnvdimm, namespace: avoid multiple sector calculations libnvdimm: remove else after return in nsio_rw_bytes() libnvdimm, namespace: fix the type of name variable libnvdimm: use consistent naming for request_mem_region() nvdimm: use the right length of "pmem" libnvdimm: check and clear poison before writing to pmem tools/testing/nvdimm: dynamic label support libnvdimm: allow a platform to force enable label support libnvdimm: use generic iostat interfaces
2016-12-18Merge branch 'for-4.10/libnvdimm' into libnvdimm-for-nextDan Williams2-1/+96
2016-12-18dax: add region 'id', 'size', and 'align' attributesDan Williams1-0/+94
While this information is available by looking at the nvdimm parent device that may not always be the case when/if we add support for other memory regions. Tooling should not depend on walking a given ancestor topology that is not guaranteed by the device's class. For example, a device-dax instance will always have a dax_region parent, but it may not always have a libnvdimm "dax" device as a grandparent. Reported-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-12-15mm: use vmf->address instead of of vmf->virtual_addressJan Kara1-2/+1
Every single user of vmf->virtual_address typed that entry to unsigned long before doing anything with it so the type of virtual_address does not really provide us any additional safety. Just use masked vmf->address which already has the appropriate type. Link: http://lkml.kernel.org/r/1479460644-25076-3-git-send-email-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-07device-dax: fix private mapping restriction, permit read-onlyDan Williams1-1/+1
Hugh notes in response to commit 4cb19355ea19 "device-dax: fail all private mapping attempts": "I think that is more restrictive than you intended: haven't tried, but I believe it rejects a PROT_READ, MAP_SHARED, O_RDONLY fd mmap, leaving no way to mmap /dev/dax without write permission to it." Indeed it does restrict read-only mappings, switch to checking VM_MAYSHARE, not VM_SHARED. Cc: <stable@vger.kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Pawel Lebioda <pawel.lebioda@intel.com> Fixes: 4cb19355ea19 ("device-dax: fail all private mapping attempts") Reported-by: Hugh Dickins <hughd@google.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-11-28libnvdimm: use consistent naming for request_mem_region()Dan Williams1-1/+2
Here is an example /proc/iomem listing for a system with 2 namespaces, one in "sector" mode and one in "memory" mode: 1fc000000-2fbffffff : Persistent Memory (legacy) 1fc000000-2fbffffff : namespace1.0 340000000-34fffffff : Persistent Memory 340000000-34fffffff : btt0.1 Here is the corresponding ndctl listing: # ndctl list [ { "dev":"namespace1.0", "mode":"memory", "size":4294967296, "blockdev":"pmem1" }, { "dev":"namespace0.0", "mode":"sector", "size":267091968, "uuid":"f7594f86-badb-4592-875f-ded577da2eaf", "sector_size":4096, "blockdev":"pmem0s" } ] Notice that the ndctl listing is purely in terms of namespace devices, while the iomem listing leaks the internal "btt0.1" implementation detail. Given that ndctl requires the namespace device name to change the mode, for example: # ndctl create-namespace --reconfig=namespace0.0 --mode=raw --force ...use the namespace name in the iomem listing to keep the claiming device name consistent across different mode settings. Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-11-16device-dax: fail all private mapping attemptsDan Williams1-2/+2
The device-dax implementation originally tried to be tricky and allow private read-only mappings, but in the process allowed writable MAP_PRIVATE + MAP_NORESERVE mappings. For simplicity and predictability just fail all private mapping attempts since device-dax memory is statically allocated and will never support overcommit. Cc: <stable@vger.kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reported-by: Pawel Lebioda <pawel.lebioda@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-10-29device-dax: check devm_nsio_enable() return valueDan Williams1-1/+3
If the dax_pmem driver is passed a resource that is already busy the driver probe attempt should fail with a message like the following: dax_pmem dax0.1: could not reserve region [mem 0x100000000-0x11fffffff] However, if we do not catch the error we crash for the obvious reason of accessing memory that is not mapped. BUG: unable to handle kernel paging request at ffffc90020001000 IP: [<ffffffff81496712>] __memcpy+0x12/0x20 [..] Call Trace: [<ffffffff815c4960>] ? nsio_rw_bytes+0x60/0x180 [<ffffffff815c6045>] nd_pfn_validate+0x75/0x320 [<ffffffff815c63a9>] nvdimm_setup_pfn+0xb9/0x5d0 [<ffffffff815c48ef>] ? devm_nsio_enable+0xff/0x110 [<ffffffff815cb699>] dax_pmem_probe+0x59/0x260 Cc: <stable@vger.kernel.org> Fixes: ab68f2622136 ("/dev/dax, pmem: direct access to persistent memory") Reported-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-10-28device-dax: fix percpu_ref_exit orderingDan Williams1-1/+1
We need to wait until the percpu_ref is released before exit. Otherwise, we sometimes lose the race and trigger this new warning that was added in v4.9 (commit a67823c1ed10 "percpu-refcount: init ->confirm_switch member properly"): WARNING: CPU: 0 PID: 3629 at lib/percpu-refcount.c:107 percpu_ref_exit+0x51/0x60 [..] Call Trace: [<ffffffff814bf093>] dump_stack+0x85/0xc2 [<ffffffff810b15db>] __warn+0xcb/0xf0 [<ffffffff810b170d>] warn_slowpath_null+0x1d/0x20 [<ffffffff814d70c1>] percpu_ref_exit+0x51/0x60 [<ffffffffa005706a>] dax_pmem_percpu_exit+0x1a/0x50 [dax_pmem] [<ffffffff81615f1f>] devm_action_release+0xf/0x20 Cc: <stable@vger.kernel.org> Fixes: ab68f2622136 ("/dev/dax, pmem: direct access to persistent memory") Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-10-28nvdimm: make CONFIG_NVDIMM_DAX 'bool'Arnd Bergmann1-1/+1
A bugfix just tried to address a randconfig build problem and introduced a variant of the same problem: with CONFIG_LIBNVDIMM=y and CONFIG_NVDIMM_DAX=m, the nvdimm module now fails to link: drivers/nvdimm/built-in.o: In function `to_nd_device_type': bus.c:(.text+0x1b5d): undefined reference to `is_nd_dax' drivers/nvdimm/built-in.o: In function `nd_region_notify_driver_action.constprop.2': region_devs.c:(.text+0x6b6c): undefined reference to `is_nd_dax' region_devs.c:(.text+0x6b8c): undefined reference to `to_nd_dax' drivers/nvdimm/built-in.o: In function `nd_region_probe': region.c:(.text+0x70f3): undefined reference to `nd_dax_create' drivers/nvdimm/built-in.o: In function `mode_show': namespace_devs.c:(.text+0xa196): undefined reference to `is_nd_dax' drivers/nvdimm/built-in.o: In function `nvdimm_namespace_common_probe': (.text+0xa55f): undefined reference to `is_nd_dax' drivers/nvdimm/built-in.o: In function `nvdimm_namespace_common_probe': (.text+0xa56e): undefined reference to `to_nd_dax' This reverts the earlier fix, making NVDIMM_DAX a 'bool' option again as it should be (it gets linked into the libnvdimm module). To fix the original problem, I'm adding a dependency on LIBNVDIMM to DEV_DAX_PMEM, which ensures we can't have that one built-in if the rest is a module. Fixes: 4e65e9381c7a ("/dev/dax: fix Kconfig dependency build breakage") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-10-08Merge branch 'for-4.9/dax' into libnvdimm-for-nextDan Williams4-232/+362
2016-10-08dax: use correct dev_t valueArnd Bergmann1-2/+2
The dev_t variable in devm_create_dax_dev() is used before it's first set: drivers/dax/dax.c: In function 'devm_create_dax_dev': drivers/dax/dax.c:205:39: error: 'dev_t' may be used uninitialized in this function [-Werror=maybe-uninitialized] inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/dax/dax.c:688:8: note: 'dev_t' was declared here This reorders the code to how it looks correct to me. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Fixes: 3bc52c45bac2 ("dax: define a unified inode/address_space for device-dax mappings") Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-10-08dax: convert devm_create_dax_dev to PTR_ERRDan Williams3-10/+16
For sub-division support we need access to the dax_dev created by devm_create_dax_dev(). Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-09-03dax: fix mapping size checkDan Williams1-1/+1
pgoff_to_phys() validates that both the starting address and the length of the mapping against the resource list. We need to check for a mapping size of PMD_SIZE not PAGE_SIZE in the pmd fault path. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-27dax: fix device-dax region baseDan Williams1-0/+3
The data offset for a dax region needs to account for a reservation in the resource range. Otherwise, device-dax is allowing mappings directly into the memmap or device-info-block area with crash signatures like the following: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: get_zone_device_page+0x11/0x30 Call Trace: follow_devmap_pmd+0x298/0x2c0 follow_page_mask+0x275/0x530 __get_user_pages+0xe3/0x750 __gfn_to_pfn_memslot+0x1b2/0x450 [kvm] tdp_page_fault+0x130/0x280 [kvm] kvm_mmu_page_fault+0x5f/0xf0 [kvm] handle_ept_violation+0x94/0x180 [kvm_intel] vmx_handle_exit+0x1d3/0x1440 [kvm_intel] kvm_arch_vcpu_ioctl_run+0x81d/0x16a0 [kvm] kvm_vcpu_ioctl+0x33c/0x620 [kvm] do_vfs_ioctl+0xa2/0x5d0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x1a/0xa4 Fixes: ab68f2622136 ("/dev/dax, pmem: direct access to persistent memory") Link: http://lkml.kernel.org/r/147205536732.1606.8994275381938837346.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Abhilash Kumar Mulumudi <m.abhilash-kumar@hpe.com> Reported-by: Toshi Kani <toshi.kani@hpe.com> Tested-by: Toshi Kani <toshi.kani@hpe.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-24dax: check resource alignment at dax region/device createDan Williams1-3/+19
All the extents of a dax-device must match the alignment of the region. Otherwise, we are unable to guarantee fault semantics of a given page size. The region must be self-consistent itself as well. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-24dax: unmap/truncate on device shutdownDan Williams1-0/+1
Invalidate all mappings of a device-dax instance when the device is unregistered. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-24dax: define a unified inode/address_space for device-dax mappingsDan Williams1-4/+146
In support of enabling resize / truncate of device-dax instances, define a pseudo-fs to provide a unified inode/address space for vm operations. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-24dax: convert to the cdev apiDan Williams2-41/+46
A goal of the device-DAX interface is to be able to support many exclusive allocations (partitions) of performance / feature differentiated memory. This count may exceed the default minors limit of 256. As a result of switching to an embedded cdev the inode-to-dax_dev conversion is simplified, as well as reference counting which can switch to the cdev kobject lifetime. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-24dax: embed a struct device in dax_devDan Williams1-85/+45
The kref in dax_dev can be made redundant if the final put_device() on the device associated with the dax_dev frees the dax_dev. This can be accomplished by embedding a struct device in struct dax_dev, open coding device_create() and specifying a custom release method. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-24dax: rename fops from dax_dev_ to dax_Dan Williams1-8/+8
Shorten the prefix of the file operations to distinguish them from operations on the struct device associated with the dax_dev. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-24dax: reorder dax_fops function definitionsDan Williams1-169/+168
In order to convert devm_create_dax_dev() to use cdev, it will need access to dax_fops. Move dax_fops and related function definitions before devm_create_dax_dev(). Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-08-24dax: cleanup needlessly global symbol warningsDan Williams2-1/+2
drivers/dax/dax.c:75:6: warning: symbol 'dax_region_put' was not declared. drivers/dax/dax.c:95:19: warning: symbol 'alloc_dax_region' was not declared. drivers/dax/dax.c:173:5: warning: symbol 'devm_create_dax_dev' was not declared. drivers/dax/pmem.c:27:17: warning: symbol 'to_dax_pmem' was not declared. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-07dax: use devm_add_action_or_reset()Sajjan, Vikas C2-12/+8
If devm_add_action() fails, we are explicitly calling the cleanup to free the resources allocated. Use the helper devm_add_action_or_reset() and return directly in case of error, since the cleanup function has been already called by the helper if there was any error. Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Vikas C Sajjan <vikas.cha.sajjan@hpe.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-05-21/dev/dax, core: file operations and dax-mmapDan Williams2-0/+323
The "Device DAX" core enables dax mappings of performance / feature differentiated memory. An open mapping or file handle keeps the backing struct device live, but new mappings are only possible while the device is enabled. Faults are handled under rcu_read_lock to synchronize with the enabled state of the device. Similar to the filesystem-dax case the backing memory may optionally have struct page entries. However, unlike fs-dax there is no support for private mappings, or mappings that are not backed by media (see use of zero-page in fs-dax). Mappings are always guaranteed to match the alignment of the dax_region. If the dax_region is configured to have a 2MB alignment, all mappings are guaranteed to be backed by a pmd entry. Contrast this determinism with the fs-dax case where pmd mappings are opportunistic. If userspace attempts to force a misaligned mapping, the driver will fail the mmap attempt. See dax_dev_check_vma() for other scenarios that are rejected, like MAP_PRIVATE mappings. Cc: Hannes Reinecke <hare@suse.de> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-05-21/dev/dax, pmem: direct access to persistent memoryDan Williams5-0/+464
Device DAX is the device-centric analogue of Filesystem DAX (CONFIG_FS_DAX). It allows memory ranges to be allocated and mapped without need of an intervening file system. Device DAX is strict, precise and predictable. Specifically this interface: 1/ Guarantees fault granularity with respect to a given page size (pte, pmd, or pud) set at configuration time. 2/ Enforces deterministic behavior by being strict about what fault scenarios are supported. For example, by forcing MADV_DONTFORK semantics and omitting MAP_PRIVATE support device-dax guarantees that a mapping always behaves/performs the same once established. It is the "what you see is what you get" access mechanism to differentiated memory vs filesystem DAX which has filesystem specific implementation semantics. Persistent memory is the first target, but the mechanism is also targeted for exclusive allocations of performance differentiated memory ranges. This commit is limited to the base device driver infrastructure to associate a dax device with pmem range. Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>