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| author | Michael Bestas <mkbestas@lineageos.org> | 2020-04-14 16:18:14 +0300 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2020-04-14 18:41:04 +0300 |
| commit | 9eb199e06bc76fb2677052c3a171b2ab917c121d (patch) | |
| tree | d92fe8bf4acb7ed72bb329b4191bc2bc7f222d73 /mm/internal.h | |
| parent | 268d6e9ab66bfd7a826050a9a651cdd6bca2f773 (diff) | |
| parent | f9991115f079363d70ce91c37d850ec4a5e065a6 (diff) | |
Merge branch 'android-4.4-p' of https://android.googlesource.com/kernel/common into lineage-17.1-caf-msm8998
This brings LA.UM.8.4.r1-05300-8x98.0 up to date with
https://android.googlesource.com/kernel/common/ android-4.4-p at commit:
f9991115f0793 Merge 4.4.219 into android-4.4-p
Conflicts:
drivers/clk/qcom/clk-rcg2.c
drivers/scsi/sd.c
drivers/usb/gadget/function/f_fs.c
drivers/usb/gadget/function/u_serial.c
Change-Id: Ifed3db0ddda828c1697e57e9f73c1b73354bebf7
Diffstat (limited to 'mm/internal.h')
| -rw-r--r-- | mm/internal.h | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/mm/internal.h b/mm/internal.h index c3533af5de8b..184e2caa9613 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -81,7 +81,8 @@ static inline void __get_page_tail_foll(struct page *page, * speculative page access (like in * page_cache_get_speculative()) on tail pages. */ - VM_BUG_ON_PAGE(atomic_read(&compound_head(page)->_count) <= 0, page); + VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(compound_head(page)), + page); if (get_page_head) atomic_inc(&compound_head(page)->_count); get_huge_page_tail(page); @@ -106,11 +107,34 @@ static inline void get_page_foll(struct page *page) * Getting a normal page or the head of a compound page * requires to already have an elevated page->_count. */ - VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page); + VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page); atomic_inc(&page->_count); } } +static inline __must_check bool try_get_page_foll(struct page *page) +{ + if (unlikely(PageTail(page))) { + if (WARN_ON_ONCE(atomic_read(&compound_head(page)->_count) <= 0)) + return false; + /* + * This is safe only because + * __split_huge_page_refcount() can't run under + * get_page_foll() because we hold the proper PT lock. + */ + __get_page_tail_foll(page, true); + } else { + /* + * Getting a normal page or the head of a compound page + * requires to already have an elevated page->_count. + */ + if (WARN_ON_ONCE(atomic_read(&page->_count) <= 0)) + return false; + atomic_inc(&page->_count); + } + return true; +} + extern unsigned long highest_memmap_pfn; /* |