Re: [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@xxxxxxxxxxxxxxx>
Fixes: ebed4bfc8da8 ("hugetlb: fix absurd HugePages_Rsvd")
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
  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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