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SubjectRe: [PATCH 3/3] hugetlbfs: remove unnecessary code after i_mmap_rwsem synchronization
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On 12/4/18 1:38 AM, Mike Kravetz wrote:
> After expanding i_mmap_rwsem use for better shared pmd and page fault/
> truncation synchronization, remove code that is no longer necessary.
>
> Cc: <stable@vger.kernel.org>
> Fixes: ebed4bfc8da8 ("hugetlb: fix absurd HugePages_Rsvd")
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> ---
> fs/hugetlbfs/inode.c | 46 +++++++++++++++-----------------------------
> mm/hugetlb.c | 21 ++++++++++----------
> 2 files changed, 25 insertions(+), 42 deletions(-)
>
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 3244147fc42b..a9c00c6ef80d 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -383,17 +383,16 @@ hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end)
> * truncation is indicated by end of range being LLONG_MAX
> * In this case, we first scan the range and release found pages.
> * After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
> - * maps and global counts. Page faults can not race with truncation
> - * in this routine. hugetlb_no_page() prevents page faults in the
> - * truncated range. It checks i_size before allocation, and again after
> - * with the page table lock for the page held. The same lock must be
> - * acquired to unmap a page.
> + * maps and global counts.
> * hole punch is indicated if end is not LLONG_MAX
> * In the hole punch case we scan the range and release found pages.
> * Only when releasing a page is the associated region/reserv map
> * deleted. The region/reserv map for ranges without associated
> - * pages are not modified. Page faults can race with hole punch.
> - * This is indicated if we find a mapped page.
> + * pages are not modified.
> + *
> + * Callers of this routine must hold the i_mmap_rwsem in write mode to prevent
> + * races with page faults.

Should this patch be merged to the previous one? Because the changes to
callers are done in the previous patch.


> + *
> * Note: If the passed end of range value is beyond the end of file, but
> * not LLONG_MAX this routine still performs a hole punch operation.
> */
> @@ -423,32 +422,14 @@ static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
>
> for (i = 0; i < pagevec_count(&pvec); ++i) {
>
-aneesh

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