[PATCH v14 086/138] mm/filemap: Add filemap_add_folio()

Matthew Wilcox (Oracle)
2021-07-15T04:47:17Z

Convert __add_to_page_cache_locked() into __filemap_add_folio().
Add an assertion to it that (for !hugetlbfs), the folio is naturally
aligned within the file. Move the prototype from mm.h to pagemap.h.
Convert add_to_page_cache_lru() into filemap_add_folio(). Add a
compatibility wrapper for unconverted callers.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
include/linux/mm.h | 7 -----
include/linux/pagemap.h | 10 ++++--
kernel/bpf/verifier.c | 2 +-
mm/filemap.c | 70 ++++++++++++++++++++---------------------
mm/folio-compat.c | 7 +++++
5 files changed, 50 insertions(+), 46 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4803f2c01367..99f5f736be64 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -213,13 +213,6 @@ int overcommit_kbytes_handler(struct ctl_table *, int, void *, size_t *,
loff_t *);
int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
loff_t *);
-/*
- * Any attempt to mark this function as static leads to build failure
- * when CONFIG_DEBUG_INFO_BTF is enabled because __add_to_page_cache_locked()
- * is referred to by BPF code. This must be visible for error injection.
- */
-int __add_to_page_cache_locked(struct page *page, struct address_space *mapping,
- pgoff_t index, gfp_t gfp, void **shadowp);

#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 848acb44ac80..19b2e3bea14c 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -877,9 +877,11 @@ static inline int fault_in_pages_readable(const char __user *uaddr, int size)
}

int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
- pgoff_t index, gfp_t gfp_mask);
+ pgoff_t index, gfp_t gfp);
int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
- pgoff_t index, gfp_t gfp_mask);
+ pgoff_t index, gfp_t gfp);
+int filemap_add_folio(struct address_space *mapping, struct folio *folio,
+ pgoff_t index, gfp_t gfp);
extern void delete_from_page_cache(struct page *page);
extern void __delete_from_page_cache(struct page *page, void *shadow);
void replace_page_cache_page(struct page *old, struct page *new);
@@ -904,6 +906,10 @@ static inline int add_to_page_cache(struct page *page,
return error;
}

+/* Must be non-static for BPF error injection */
+int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
+ pgoff_t index, gfp_t gfp, void **shadowp);
+
/**
* struct readahead_control - Describes a readahead request.
*
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 42a4063de7cd..f0a4f8b818e4 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13015,7 +13015,7 @@ BTF_SET_START(btf_non_sleepable_error_inject)
/* Three functions below can be called from sleepable and non-sleepable context.
* Assume non-sleepable from bpf safety point of view.
*/
-BTF_ID(func, __add_to_page_cache_locked)
+BTF_ID(func, __filemap_add_folio)
BTF_ID(func, should_fail_alloc_page)
BTF_ID(func, should_failslab)
BTF_SET_END(btf_non_sleepable_error_inject)
diff --git a/mm/filemap.c b/mm/filemap.c
index 54989a32d6a8..4e34383fd894 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -855,26 +855,25 @@ void replace_page_cache_page(struct page *old, struct page *new)
}
EXPORT_SYMBOL_GPL(replace_page_cache_page);

-noinline int __add_to_page_cache_locked(struct page *page,
- struct address_space *mapping,
- pgoff_t offset, gfp_t gfp,
- void **shadowp)
+noinline int __filemap_add_folio(struct address_space *mapping,
+ struct folio *folio, pgoff_t index, gfp_t gfp, void **shadowp)
{
- XA_STATE(xas, &mapping->i_pages, offset);
- int huge = PageHuge(page);
+ XA_STATE(xas, &mapping->i_pages, index);
+ int huge = folio_test_hugetlb(folio);
int error;
bool charged = false;

- VM_BUG_ON_PAGE(!PageLocked(page), page);
- VM_BUG_ON_PAGE(PageSwapBacked(page), page);
+ VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
+ VM_BUG_ON_FOLIO(folio_test_swapbacked(folio), folio);
mapping_set_update(&xas, mapping);

- get_page(page);
- page->mapping = mapping;
- page->index = offset;
+ folio_get(folio);
+ folio->mapping = mapping;
+ folio->index = index;

if (!huge) {
- error = mem_cgroup_charge(page_folio(page), NULL, gfp);
+ error = mem_cgroup_charge(folio, NULL, gfp);
+ VM_BUG_ON_FOLIO(index & (folio_nr_pages(folio) - 1), folio);
if (error)
goto error;
charged = true;
@@ -886,7 +885,7 @@ noinline int __add_to_page_cache_locked(struct page *page,
unsigned int order = xa_get_order(xas.xa, xas.xa_index);
void *entry, *old = NULL;

- if (order > thp_order(page))
+ if (order > folio_order(folio))
xas_split_alloc(&xas, xa_load(xas.xa, xas.xa_index),
order, gfp);
xas_lock_irq(&xas);
@@ -903,13 +902,13 @@ noinline int __add_to_page_cache_locked(struct page *page,
*shadowp = old;
/* entry may have been split before we acquired lock */
order = xa_get_order(xas.xa, xas.xa_index);
- if (order > thp_order(page)) {
+ if (order > folio_order(folio)) {
xas_split(&xas, old, order);
xas_reset(&xas);
}
}

- xas_store(&xas, page);
+ xas_store(&xas, folio);
if (xas_error(&xas))
goto unlock;

@@ -917,7 +916,7 @@ noinline int __add_to_page_cache_locked(struct page *page,

/* hugetlb pages do not participate in page cache accounting */
if (!huge)
- __inc_lruvec_page_state(page, NR_FILE_PAGES);
+ __lruvec_stat_add_folio(folio, NR_FILE_PAGES);
unlock:
xas_unlock_irq(&xas);
} while (xas_nomem(&xas, gfp));
@@ -925,19 +924,19 @@ noinline int __add_to_page_cache_locked(struct page *page,
if (xas_error(&xas)) {
error = xas_error(&xas);
if (charged)
- mem_cgroup_uncharge(page_folio(page));
+ mem_cgroup_uncharge(folio);
goto error;
}

- trace_mm_filemap_add_to_page_cache(page);
+ trace_mm_filemap_add_to_page_cache(&folio->page);
return 0;
error:
- page->mapping = NULL;
+ folio->mapping = NULL;
/* Leave page->index set: truncation relies upon it */
- put_page(page);
+ folio_put(folio);
return error;
}
-ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO);
+ALLOW_ERROR_INJECTION(__filemap_add_folio, ERRNO);

/**
* add_to_page_cache_locked - add a locked page to the pagecache
@@ -954,39 +953,38 @@ ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO);
int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
pgoff_t offset, gfp_t gfp_mask)
{
- return __add_to_page_cache_locked(page, mapping, offset,
+ return __filemap_add_folio(mapping, page_folio(page), offset,
gfp_mask, NULL);
}
EXPORT_SYMBOL(add_to_page_cache_locked);

-int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
- pgoff_t offset, gfp_t gfp_mask)
+int filemap_add_folio(struct address_space *mapping, struct folio *folio,
+ pgoff_t index, gfp_t gfp)
{
void *shadow = NULL;
int ret;

- __SetPageLocked(page);
- ret = __add_to_page_cache_locked(page, mapping, offset,
- gfp_mask, &shadow);
+ __folio_set_locked(folio);
+ ret = __filemap_add_folio(mapping, folio, index, gfp, &shadow);
if (unlikely(ret))
- __ClearPageLocked(page);
+ __folio_clear_locked(folio);
else {
/*
- * The page might have been evicted from cache only
+ * The folio might have been evicted from cache only
* recently, in which case it should be activated like
- * any other repeatedly accessed page.
- * The exception is pages getting rewritten; evicting other
+ * any other repeatedly accessed folio.
+ * The exception is folios getting rewritten; evicting other
* data from the working set, only to cache data that will
* get overwritten with something else, is a waste of memory.
*/
- WARN_ON_ONCE(PageActive(page));
- if (!(gfp_mask & __GFP_WRITE) && shadow)
- workingset_refault(page_folio(page), shadow);
- lru_cache_add(page);
+ WARN_ON_ONCE(folio_test_active(folio));
+ if (!(gfp & __GFP_WRITE) && shadow)
+ workingset_refault(folio, shadow);
+ folio_add_lru(folio);
}
return ret;
}
-EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
+EXPORT_SYMBOL_GPL(filemap_add_folio);

#ifdef CONFIG_NUMA
struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order)
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 6de3cd78a4ae..6b19bc4ed6b0 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -108,3 +108,10 @@ void lru_cache_add(struct page *page)
folio_add_lru(page_folio(page));
}
EXPORT_SYMBOL(lru_cache_add);
+
+int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
+ pgoff_t index, gfp_t gfp)
+{
+ return filemap_add_folio(mapping, page_folio(page), index, gfp);
+}
+EXPORT_SYMBOL(add_to_page_cache_lru);
--
2.30.2