mm: introduce page_size()

Patch series "Make working with compound pages easier", v2.

These three patches add three helpers and convert the appropriate
places to use them.

This patch (of 3):

It's unnecessarily hard to find out the size of a potentially huge page.
Replace 'PAGE_SIZE << compound_order(page)' with page_size(page).

Link: http://lkml.kernel.org/r/20190721104612.19120-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

17 files changed, 35 insertions, 38 deletions

diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 6ecbda87ee46..4c7ebe094a83 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -204,8 +204,7 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page)
          * coherent with the kernels mapping.
          */
         if (!PageHighMem(page)) {
-                size_t page_size = PAGE_SIZE << compound_order(page);
-                __cpuc_flush_dcache_area(page_address(page), page_size);
+                __cpuc_flush_dcache_area(page_address(page), page_size(page));
         } else {
                 unsigned long i;
                 if (cache_is_vipt_nonaliasing()) {
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index dc19300309d2..ac485163a4a7 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -56,8 +56,7 @@ void __sync_icache_dcache(pte_t pte)
         struct page *page = pte_page(pte);
 
         if (!test_and_set_bit(PG_dcache_clean, &page->flags))
-                sync_icache_aliases(page_address(page),
-                                    PAGE_SIZE << compound_order(page));
+                sync_icache_aliases(page_address(page), page_size(page));
 }
 EXPORT_SYMBOL_GPL(__sync_icache_dcache);
 
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 678b98a09c85..bf9df2625bc8 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -64,7 +64,7 @@ __ia64_sync_icache_dcache (pte_t pte)
         if (test_bit(PG_arch_1, &page->flags))
                 return;                         /* i-cache is already coherent with d-cache */
 
-        flush_icache_range(addr, addr + (PAGE_SIZE << compound_order(page)));
+        flush_icache_range(addr, addr + page_size(page));
         set_bit(PG_arch_1, &page->flags);       /* mark page as clean */
 }
 
diff --git a/drivers/crypto/chelsio/chtls/chtls_io.c b/drivers/crypto/chelsio/chtls/chtls_io.c
index c70cb5f272cf..0891ab829b1b 100644
--- a/drivers/crypto/chelsio/chtls/chtls_io.c
+++ b/drivers/crypto/chelsio/chtls/chtls_io.c
@@ -1078,7 +1078,7 @@ new_buf:
                         bool merge;
 
                         if (page)
-                                pg_size <<= compound_order(page);
+                                pg_size = page_size(page);
                         if (off < pg_size &&
                             skb_can_coalesce(skb, i, page, off)) {
                                 merge = 1;
@@ -1105,8 +1105,7 @@ new_buf:
                                                            __GFP_NORETRY,
                                                            order);
                                         if (page)
-                                                pg_size <<=
-                                                        compound_order(page);
+                                                pg_size <<= order;
                                 }
                                 if (!page) {
                                         page = alloc_page(gfp);
diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index aa8d8425be25..b83a1d16bd89 100644
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -120,7 +120,7 @@ static int ion_system_heap_allocate(struct ion_heap *heap,
                 if (!page)
                         goto free_pages;
                 list_add_tail(&page->lru, &pages);
-                size_remaining -= PAGE_SIZE << compound_order(page);
+                size_remaining -= page_size(page);
                 max_order = compound_order(page);
                 i++;
         }
@@ -133,7 +133,7 @@ static int ion_system_heap_allocate(struct ion_heap *heap,
 
         sg = table->sgl;
         list_for_each_entry_safe(page, tmp_page, &pages, lru) {
-                sg_set_page(sg, page, PAGE_SIZE << compound_order(page), 0);
+                sg_set_page(sg, page, page_size(page), 0);
                 sg = sg_next(sg);
                 list_del(&page->lru);
         }
diff --git a/drivers/target/tcm_fc/tfc_io.c b/drivers/target/tcm_fc/tfc_io.c
index a254792d882c..1354a157e9af 100644
--- a/drivers/target/tcm_fc/tfc_io.c
+++ b/drivers/target/tcm_fc/tfc_io.c
@@ -136,8 +136,7 @@ int ft_queue_data_in(struct se_cmd *se_cmd)
                                            page, off_in_page, tlen);
                         fr_len(fp) += tlen;
                         fp_skb(fp)->data_len += tlen;
-                        fp_skb(fp)->truesize +=
-                                        PAGE_SIZE << compound_order(page);
+                        fp_skb(fp)->truesize += page_size(page);
                 } else {
                         BUG_ON(!page);
                         from = kmap_atomic(page + (mem_off >> PAGE_SHIFT));
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0dadbdbead0f..f83de4c6a826 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3319,7 +3319,7 @@ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
         }
 
         page = virt_to_head_page(ptr);
-        if (sz > (PAGE_SIZE << compound_order(page)))
+        if (sz > page_size(page))
                 return -EINVAL;
 
         pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index edfca4278319..53fc34f930d0 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -454,7 +454,7 @@ static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 static inline struct hstate *page_hstate(struct page *page)
 {
         VM_BUG_ON_PAGE(!PageHuge(page), page);
-        return size_to_hstate(PAGE_SIZE << compound_order(page));
+        return size_to_hstate(page_size(page));
 }
 
 static inline unsigned hstate_index_to_shift(unsigned index)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6e79b3df1582..d46d5585e2a2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -805,6 +805,12 @@ static inline void set_compound_order(struct page *page, unsigned int order)
         page[1].compound_order = order;
 }
 
+/* Returns the number of bytes in this potentially compound page. */
+static inline unsigned long page_size(struct page *page)
+{
+        return PAGE_SIZE << compound_order(page);
+}
+
 void free_compound_page(struct page *page);
 
 #ifdef CONFIG_MMU
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index f1e0569b4539..639d5e7014c1 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -878,7 +878,7 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
         head = compound_head(page);
         v += (page - head) << PAGE_SHIFT;
 
-        if (likely(n <= v && v <= (PAGE_SIZE << compound_order(head))))
+        if (likely(n <= v && v <= (page_size(head))))
                 return true;
         WARN_ON(1);
         return false;
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 6b6f1198c72b..307631d9c62b 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -338,8 +338,7 @@ void kasan_poison_slab(struct page *page)
 
         for (i = 0; i < (1 << compound_order(page)); i++)
                 page_kasan_tag_reset(page + i);
-        kasan_poison_shadow(page_address(page),
-                        PAGE_SIZE << compound_order(page),
+        kasan_poison_shadow(page_address(page), page_size(page),
                         KASAN_KMALLOC_REDZONE);
 }
 
@@ -542,7 +541,7 @@ void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
         page = virt_to_page(ptr);
         redzone_start = round_up((unsigned long)(ptr + size),
                                 KASAN_SHADOW_SCALE_SIZE);
-        redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
+        redzone_end = (unsigned long)ptr + page_size(page);
 
         kasan_unpoison_shadow(ptr, size);
         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
@@ -578,8 +577,7 @@ void kasan_poison_kfree(void *ptr, unsigned long ip)
                         kasan_report_invalid_free(ptr, ip);
                         return;
                 }
-                kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
-                                KASAN_FREE_PAGE);
+                kasan_poison_shadow(ptr, page_size(page), KASAN_FREE_PAGE);
         } else {
                 __kasan_slab_free(page->slab_cache, ptr, ip, false);
         }
diff --git a/mm/nommu.c b/mm/nommu.c
index fed1b6e9c89b..99b7ec318824 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -108,7 +108,7 @@ unsigned int kobjsize(const void *objp)
          * The ksize() function is only guaranteed to work for pointers
          * returned by kmalloc(). So handle arbitrary pointers here.
          */
-        return PAGE_SIZE << compound_order(page);
+        return page_size(page);
 }
 
 /**
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 11df03e71288..eff4b4520c8d 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -153,8 +153,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 
         if (unlikely(PageHuge(pvmw->page))) {
                 /* when pud is not present, pte will be NULL */
-                pvmw->pte = huge_pte_offset(mm, pvmw->address,
-                                            PAGE_SIZE << compound_order(page));
+                pvmw->pte = huge_pte_offset(mm, pvmw->address, page_size(page));
                 if (!pvmw->pte)
                         return false;
 
diff --git a/mm/rmap.c b/mm/rmap.c
index 31352bba197d..f401732b20e8 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -898,8 +898,7 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
          */
         mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE,
                                 0, vma, vma->vm_mm, address,
-                                min(vma->vm_end, address +
-                                    (PAGE_SIZE << compound_order(page))));
+                                min(vma->vm_end, address + page_size(page)));
         mmu_notifier_invalidate_range_start(&range);
 
         while (page_vma_mapped_walk(&pvmw)) {
@@ -1372,8 +1371,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
          */
         mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
                                 address,
-                                min(vma->vm_end, address +
-                                    (PAGE_SIZE << compound_order(page))));
+                                min(vma->vm_end, address + page_size(page)));
         if (PageHuge(page)) {
                 /*
                  * If sharing is possible, start and end will be adjusted
diff --git a/mm/slob.c b/mm/slob.c
index 7f421d0ca9ab..cf377beab962 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -539,7 +539,7 @@ size_t __ksize(const void *block)
 
         sp = virt_to_page(block);
         if (unlikely(!PageSlab(sp)))
-                return PAGE_SIZE << compound_order(sp);
+                return page_size(sp);
 
         align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
         m = (unsigned int *)(block - align);
diff --git a/mm/slub.c b/mm/slub.c
index 17fe1cac11fb..42c1b3af3c98 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -829,7 +829,7 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
                 return 1;
 
         start = page_address(page);
-        length = PAGE_SIZE << compound_order(page);
+        length = page_size(page);
         end = start + length;
         remainder = length % s->size;
         if (!remainder)
@@ -1074,13 +1074,14 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page,
         init_tracking(s, object);
 }
 
-static void setup_page_debug(struct kmem_cache *s, void *addr, int order)
+static
+void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr)
 {
         if (!(s->flags & SLAB_POISON))
                 return;
 
         metadata_access_enable();
-        memset(addr, POISON_INUSE, PAGE_SIZE << order);
+        memset(addr, POISON_INUSE, page_size(page));
         metadata_access_disable();
 }
 
@@ -1340,8 +1341,8 @@ slab_flags_t kmem_cache_flags(unsigned int object_size,
 #else /* !CONFIG_SLUB_DEBUG */
 static inline void setup_object_debug(struct kmem_cache *s,
                         struct page *page, void *object) {}
-static inline void setup_page_debug(struct kmem_cache *s,
-                        void *addr, int order) {}
+static inline
+void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr) {}
 
 static inline int alloc_debug_processing(struct kmem_cache *s,
         struct page *page, void *object, unsigned long addr) { return 0; }
@@ -1639,7 +1640,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
         struct kmem_cache_order_objects oo = s->oo;
         gfp_t alloc_gfp;
         void *start, *p, *next;
-        int idx, order;
+        int idx;
         bool shuffle;
 
         flags &= gfp_allowed_mask;
@@ -1673,7 +1674,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
         page->objects = oo_objects(oo);
 
-        order = compound_order(page);
         page->slab_cache = s;
         __SetPageSlab(page);
         if (page_is_pfmemalloc(page))
@@ -1683,7 +1683,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
         start = page_address(page);
 
-        setup_page_debug(s, start, order);
+        setup_page_debug(s, page, start);
 
         shuffle = shuffle_freelist(s, page);
 
@@ -3932,7 +3932,7 @@ size_t __ksize(const void *object)
 
         if (unlikely(!PageSlab(page))) {
                 WARN_ON(!PageCompound(page));
-                return PAGE_SIZE << compound_order(page);
+                return page_size(page);
         }
 
         return slab_ksize(page->slab_cache);
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index c2f1af3b6a7c..fa8fbb8fa3c8 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -977,7 +977,7 @@ static int xsk_mmap(struct file *file, struct socket *sock,
         /* Matches the smp_wmb() in xsk_init_queue */
         smp_rmb();
         qpg = virt_to_head_page(q->ring);
-        if (size > (PAGE_SIZE << compound_order(qpg)))
+        if (size > page_size(qpg))
                 return -EINVAL;
 
         pfn = virt_to_phys(q->ring) >> PAGE_SHIFT;