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@@ -1707,6 +1707,47 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end,
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return 1;
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}
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+static void gup_pgd_range(unsigned long addr, unsigned long end,
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+ int write, struct page **pages, int *nr)
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+{
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+ unsigned long next;
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+ pgd_t *pgdp;
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+
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+ pgdp = pgd_offset(current->mm, addr);
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+ do {
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+ pgd_t pgd = READ_ONCE(*pgdp);
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+
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+ next = pgd_addr_end(addr, end);
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+ if (pgd_none(pgd))
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+ return;
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+ if (unlikely(pgd_huge(pgd))) {
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+ if (!gup_huge_pgd(pgd, pgdp, addr, next, write,
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+ pages, nr))
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+ return;
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+ } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) {
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+ if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr,
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+ PGDIR_SHIFT, next, write, pages, nr))
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+ return;
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+ } else if (!gup_p4d_range(pgd, addr, next, write, pages, nr))
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+ return;
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+ } while (pgdp++, addr = next, addr != end);
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+}
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+
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+#ifndef gup_fast_permitted
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+/*
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+ * Check if it's allowed to use __get_user_pages_fast() for the range, or
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+ * we need to fall back to the slow version:
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+ */
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+bool gup_fast_permitted(unsigned long start, int nr_pages, int write)
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+{
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+ unsigned long len, end;
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+
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+ len = (unsigned long) nr_pages << PAGE_SHIFT;
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+ end = start + len;
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+ return end >= start;
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+}
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+#endif
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+
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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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@@ -1714,10 +1755,8 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end,
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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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- struct mm_struct *mm = current->mm;
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unsigned long addr, len, end;
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- unsigned long next, flags;
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- pgd_t *pgdp;
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+ unsigned long flags;
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int nr = 0;
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start &= PAGE_MASK;
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@@ -1741,45 +1780,15 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
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* block IPIs that come from THPs splitting.
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*/
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- local_irq_save(flags);
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- pgdp = pgd_offset(mm, addr);
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- do {
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- pgd_t pgd = READ_ONCE(*pgdp);
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-
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- next = pgd_addr_end(addr, end);
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- if (pgd_none(pgd))
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- break;
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- if (unlikely(pgd_huge(pgd))) {
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- if (!gup_huge_pgd(pgd, pgdp, addr, next, write,
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- pages, &nr))
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- break;
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- } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) {
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- if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr,
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- PGDIR_SHIFT, next, write, pages, &nr))
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- break;
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- } else if (!gup_p4d_range(pgd, addr, next, write, pages, &nr))
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- break;
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- } while (pgdp++, addr = next, addr != end);
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- local_irq_restore(flags);
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+ if (gup_fast_permitted(start, nr_pages, write)) {
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+ local_irq_save(flags);
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+ gup_pgd_range(addr, end, write, pages, &nr);
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+ local_irq_restore(flags);
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+ }
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return nr;
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}
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-#ifndef gup_fast_permitted
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-/*
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- * Check if it's allowed to use __get_user_pages_fast() for the range, or
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- * we need to fall back to the slow version:
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- */
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-bool gup_fast_permitted(unsigned long start, int nr_pages, int write)
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-{
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- unsigned long len, end;
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-
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- len = (unsigned long) nr_pages << PAGE_SHIFT;
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- end = start + len;
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- return end >= start;
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-}
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-#endif
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-
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/**
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* get_user_pages_fast() - pin user pages in memory
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* @start: starting user address
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@@ -1799,12 +1808,22 @@ bool gup_fast_permitted(unsigned long start, int nr_pages, int write)
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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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+ unsigned long addr, len, end;
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int nr = 0, ret = 0;
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start &= PAGE_MASK;
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+ addr = start;
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+ len = (unsigned long) nr_pages << PAGE_SHIFT;
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+ end = start + len;
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+
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+ if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
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+ (void __user *)start, len)))
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+ return 0;
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if (gup_fast_permitted(start, nr_pages, write)) {
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- nr = __get_user_pages_fast(start, nr_pages, write, pages);
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+ local_irq_disable();
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+ gup_pgd_range(addr, end, write, pages, &nr);
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+ local_irq_enable();
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ret = nr;
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}
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