forked from luck/tmp_suning_uos_patched
mm/gup.c: document return value
__get_user_pages_fast handles errors differently from get_user_pages_fast: the former always returns the number of pages pinned, the later might return a negative error code. Link: http://lkml.kernel.org/r/1522962072-182137-6-git-send-email-mst@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -178,6 +178,8 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
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/*
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* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
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* back to the regular GUP.
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* Note a difference with get_user_pages_fast: this always returns the
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* number of pages pinned, 0 if no pages were pinned.
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*/
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int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
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struct page **pages)
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@ -220,6 +220,8 @@ static inline int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr,
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/*
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* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
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* back to the regular GUP.
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* Note a difference with get_user_pages_fast: this always returns the
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* number of pages pinned, 0 if no pages were pinned.
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*/
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int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
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struct page **pages)
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@ -160,6 +160,8 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
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/*
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* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
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* back to the regular GUP.
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* Note a difference with get_user_pages_fast: this always returns the
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* number of pages pinned, 0 if no pages were pinned.
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*/
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int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
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struct page **pages)
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@ -193,6 +193,10 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
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return 1;
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}
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/*
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* Note a difference with get_user_pages_fast: this always returns the
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* number of pages pinned, 0 if no pages were pinned.
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*/
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int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
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struct page **pages)
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{
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4
mm/gup.c
4
mm/gup.c
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@ -1740,7 +1740,9 @@ bool gup_fast_permitted(unsigned long start, int nr_pages, int write)
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/*
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* Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to
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* the regular GUP. It will only return non-negative values.
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* the regular GUP.
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* Note a difference with get_user_pages_fast: this always returns the
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* number of pages pinned, 0 if no pages were pinned.
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*/
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int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
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struct page **pages)
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@ -297,8 +297,10 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
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/*
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* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
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* back to the regular GUP.
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* If the architecture not support this function, simply return with no
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* page pinned
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* Note a difference with get_user_pages_fast: this always returns the
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* number of pages pinned, 0 if no pages were pinned.
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* If the architecture does not support this function, simply return with no
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* pages pinned.
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*/
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int __weak __get_user_pages_fast(unsigned long start,
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int nr_pages, int write, struct page **pages)
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