diff options
author | Dave Airlie <airlied@redhat.com> | 2019-04-15 15:51:49 +1000 |
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committer | Dave Airlie <airlied@redhat.com> | 2019-04-15 15:51:49 +1000 |
commit | f06ddb53096b4cddad2c530125a78a3c2a1d28a4 (patch) | |
tree | 36a05922af22272dc82357ce82be21a3a9214bd0 /include/linux/mm.h | |
parent | ecc4946f11a07884f230450a6d5a92337bc21375 (diff) | |
parent | dc4060a5dc2557e6b5aa813bf5b73677299d62d2 (diff) |
BackMerge v5.1-rc5 into drm-next
Need rc5 for udl fix to add udl cleanups on top.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r-- | include/linux/mm.h | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 76769749b5a5..6b10c21630f5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -966,6 +966,10 @@ static inline bool is_pci_p2pdma_page(const struct page *page) } #endif /* CONFIG_DEV_PAGEMAP_OPS */ +/* 127: arbitrary random number, small enough to assemble well */ +#define page_ref_zero_or_close_to_overflow(page) \ + ((unsigned int) page_ref_count(page) + 127u <= 127u) + static inline void get_page(struct page *page) { page = compound_head(page); @@ -973,8 +977,17 @@ static inline void get_page(struct page *page) * Getting a normal page or the head of a compound page * requires to already have an elevated page->_refcount. */ - VM_BUG_ON_PAGE(page_ref_count(page) <= 0, page); + VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page); + page_ref_inc(page); +} + +static inline __must_check bool try_get_page(struct page *page) +{ + page = compound_head(page); + if (WARN_ON_ONCE(page_ref_count(page) <= 0)) + return false; page_ref_inc(page); + return true; } static inline void put_page(struct page *page) |