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author | Jason Gunthorpe <jgg@mellanox.com> | 2019-04-24 16:20:34 -0300 |
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committer | Jason Gunthorpe <jgg@mellanox.com> | 2019-04-24 16:20:34 -0300 |
commit | 449a224c10a48d047c799c5c5d3b22d6aec98c60 (patch) | |
tree | 7ecff2cce22ad3875b70a772eae55a443752cfce /mm/hugetlb.c | |
parent | IB/hfi1: Remove reference to RHF.VCRCErr (diff) | |
parent | RDMA: Remove rdma_user_mmap_page (diff) | |
download | linux-dev-449a224c10a48d047c799c5c5d3b22d6aec98c60.tar.xz linux-dev-449a224c10a48d047c799c5c5d3b22d6aec98c60.zip |
Merge branch 'rdma_mmap' into rdma.git for-next
Jason Gunthorpe says:
====================
Upon review it turns out there are some long standing problems in BAR
mapping area:
* BAR pages intended for read-only can be switched to writable via mprotect.
* Missing use of rdma_user_mmap_io for the mlx5 clock BAR page.
* Disassociate causes SIGBUS when touching the pages.
* CPU pages are being mapped through to the process via remap_pfn_range
instead of the more appropriate vm_insert_page, causing weird behaviors
during disassociation.
This series adds the missing VM_* flag manipulation, adds faulting a zero
page for disassociation and revises the CPU page mappings to use
vm_insert_page.
====================
For dependencies this branch is based on for-rc from
git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git
* branch 'rdma_mmap':
RDMA: Remove rdma_user_mmap_page
RDMA/mlx5: Use get_zeroed_page() for clock_info
RDMA/ucontext: Fix regression with disassociate
RDMA/mlx5: Use rdma_user_map_io for mapping BAR pages
RDMA/mlx5: Do not allow the user to write to the clock page
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r-- | mm/hugetlb.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 97b1e0290c66..6cdc7b2d9100 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4299,6 +4299,19 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; page = pte_page(huge_ptep_get(pte)); + + /* + * Instead of doing 'try_get_page()' below in the same_page + * loop, just check the count once here. + */ + if (unlikely(page_count(page) <= 0)) { + if (pages) { + spin_unlock(ptl); + remainder = 0; + err = -ENOMEM; + break; + } + } same_page: if (pages) { pages[i] = mem_map_offset(page, pfn_offset); |