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Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Browse Source 
Pull libnvdimm fixes from Dan Williams:
 "A 4.16 regression fix, three fixes for -stable, and a cleanup fix:

   - During the merge window support for the new ACPI NVDIMM Platform
     Capabilities structure disabled support for "deep flush", a
     force-unit- access like mechanism for persistent memory. Restore
     that mechanism.

   - VFIO like RDMA is yet one more memory registration / pinning
     interface that is incompatible with Filesystem-DAX. Disable long
     term pins of Filesystem-DAX mappings via VFIO.

   - The Filesystem-DAX detection to prevent long terms pins mistakenly
     also disabled Device-DAX pins which are not subject to the same
     block- map collision concerns.

   - Similar to the setup path, softlockup warnings can trigger in the
     shutdown path for large persistent memory namespaces. Teach
     for_each_device_pfn() to perform cond_resched() in all cases.

   - Boaz noticed that the might_sleep() in dax_direct_access() is stale
     as of the v4.15 kernel.

  These have received a build success notification from the 0day robot,
  and the longterm pin fixes have appeared in -next. However, I recently
  rebased the tree to remove some other fixes that need to be reworked
  after review feedback.

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  memremap: fix softlockup reports at teardown
  libnvdimm: re-enable deep flush for pmem devices via fsync()
  vfio: disable filesystem-dax page pinning
  dax: fix vma_is_fsdax() helper
  dax: ->direct_access does not sleep anymore
This commit is contained in:
Linus Torvalds 2018-03-03 14:32:00 -08:00
commit 20f14172cb
5 changed files with 27 additions and 17 deletions
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6
drivers/dax/super.c
View File

@ -246,12 +246,6 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
{
long avail;
/*
* The device driver is allowed to sleep, in order to make the
* memory directly accessible.
*/
might_sleep();
if (!dax_dev)
return -EOPNOTSUPP;

3
drivers/nvdimm/pmem.c
View File

@ -335,8 +335,7 @@ static int pmem_attach_disk(struct device *dev,
dev_warn(dev, "unable to guarantee persistence of writes\n");
fua = 0;
}
wbc = nvdimm_has_cache(nd_region) &&
!test_bit(ND_REGION_PERSIST_CACHE, &nd_region->flags);
wbc = nvdimm_has_cache(nd_region);
if (!devm_request_mem_region(dev, res->start, resource_size(res),
dev_name(&ndns->dev))) {

18
drivers/vfio/vfio_iommu_type1.c
View File

@ -338,11 +338,12 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
{
struct page *page[1];
struct vm_area_struct *vma;
struct vm_area_struct *vmas[1];
int ret;
if (mm == current->mm) {
ret = get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE),
page);
ret = get_user_pages_longterm(vaddr, 1, !!(prot & IOMMU_WRITE),
page, vmas);
} else {
unsigned int flags = 0;
@ -351,7 +352,18 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
down_read(&mm->mmap_sem);
ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page,
NULL, NULL);
vmas, NULL);
/*
* The lifetime of a vaddr_get_pfn() page pin is
* userspace-controlled. In the fs-dax case this could
* lead to indefinite stalls in filesystem operations.
* Disallow attempts to pin fs-dax pages via this
* interface.
*/
if (ret > 0 && vma_is_fsdax(vmas[0])) {
ret = -EOPNOTSUPP;
put_page(page[0]);
}
up_read(&mm->mmap_sem);
}

2
include/linux/fs.h
View File

@ -3198,7 +3198,7 @@ static inline bool vma_is_fsdax(struct vm_area_struct *vma)
if (!vma_is_dax(vma))
return false;
inode = file_inode(vma->vm_file);
if (inode->i_mode == S_IFCHR)
if (S_ISCHR(inode->i_mode))
return false; /* device-dax */
return true;
}

15
kernel/memremap.c
View File

@ -275,8 +275,15 @@ static unsigned long pfn_end(struct dev_pagemap *pgmap)
return (res->start + resource_size(res)) >> PAGE_SHIFT;
}
static unsigned long pfn_next(unsigned long pfn)
{
if (pfn % 1024 == 0)
cond_resched();
return pfn + 1;
}
#define for_each_device_pfn(pfn, map) \
for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)
for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
static void devm_memremap_pages_release(void *data)
{
@ -337,10 +344,10 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
resource_size_t align_start, align_size, align_end;
struct vmem_altmap *altmap = pgmap->altmap_valid ?
&pgmap->altmap : NULL;
struct resource *res = &pgmap->res;
unsigned long pfn, pgoff, order;
pgprot_t pgprot = PAGE_KERNEL;
int error, nid, is_ram, i = 0;
struct resource *res = &pgmap->res;
int error, nid, is_ram;
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
@ -409,8 +416,6 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
list_del(&page->lru);
page->pgmap = pgmap;
percpu_ref_get(pgmap->ref);
if (!(++i % 1024))
cond_resched();
}
devm_add_action(dev, devm_memremap_pages_release, pgmap);