1 files changed, 98 insertions, 79 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index baafbf324c9f..bf6219d9aaac 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1669,46 +1669,47 @@ static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait)
 
 /*
  * Return values:
- * true - folio is locked; mmap_lock is still held.
- * false - folio is not locked.
- *     mmap_lock has been released (mmap_read_unlock(), unless flags had both
- *     FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_RETRY_NOWAIT set, in
- *     which case mmap_lock is still held.
- *
- * If neither ALLOW_RETRY nor KILLABLE are set, will always return true
- * with the folio locked and the mmap_lock unperturbed.
+ * 0 - folio is locked.
+ * non-zero - folio is not locked.
+ *     mmap_lock or per-VMA lock has been released (mmap_read_unlock() or
+ *     vma_end_read()), unless flags had both FAULT_FLAG_ALLOW_RETRY and
+ *     FAULT_FLAG_RETRY_NOWAIT set, in which case the lock is still held.
+ *
+ * If neither ALLOW_RETRY nor KILLABLE are set, will always return 0
+ * with the folio locked and the mmap_lock/per-VMA lock is left unperturbed.
  */
-bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
-			 unsigned int flags)
+vm_fault_t __folio_lock_or_retry(struct folio *folio, struct vm_fault *vmf)
 {
+	unsigned int flags = vmf->flags;
+
 	if (fault_flag_allow_retry_first(flags)) {
 		/*
-		 * CAUTION! In this case, mmap_lock is not released
-		 * even though return 0.
+		 * CAUTION! In this case, mmap_lock/per-VMA lock is not
+		 * released even though returning VM_FAULT_RETRY.
 		 */
 		if (flags & FAULT_FLAG_RETRY_NOWAIT)
-			return false;
+			return VM_FAULT_RETRY;
 
-		mmap_read_unlock(mm);
+		release_fault_lock(vmf);
 		if (flags & FAULT_FLAG_KILLABLE)
 			folio_wait_locked_killable(folio);
 		else
 			folio_wait_locked(folio);
-		return false;
+		return VM_FAULT_RETRY;
 	}
 	if (flags & FAULT_FLAG_KILLABLE) {
 		bool ret;
 
 		ret = __folio_lock_killable(folio);
 		if (ret) {
-			mmap_read_unlock(mm);
-			return false;
+			release_fault_lock(vmf);
+			return VM_FAULT_RETRY;
 		}
 	} else {
 		__folio_lock(folio);
 	}
 
-	return true;
+	return 0;
 }
 
 /**
@@ -2080,7 +2081,7 @@ unsigned find_lock_entries(struct address_space *mapping, pgoff_t *start,
 		if (!xa_is_value(folio)) {
 			if (folio->index < *start)
 				goto put;
-			if (folio->index + folio_nr_pages(folio) - 1 > end)
+			if (folio_next_index(folio) - 1 > end)
 				goto put;
 			if (!folio_trylock(folio))
 				goto put;
@@ -2172,16 +2173,6 @@ out:
 }
 EXPORT_SYMBOL(filemap_get_folios);
 
-static inline
-bool folio_more_pages(struct folio *folio, pgoff_t index, pgoff_t max)
-{
-	if (!folio_test_large(folio) || folio_test_hugetlb(folio))
-		return false;
-	if (index >= max)
-		return false;
-	return index < folio->index + folio_nr_pages(folio) - 1;
-}
-
 /**
  * filemap_get_folios_contig - Get a batch of contiguous folios
  * @mapping:	The address_space to search
@@ -2247,7 +2238,7 @@ update_start:
 		if (folio_test_hugetlb(folio))
 			*start = folio->index + 1;
 		else
-			*start = folio->index + folio_nr_pages(folio);
+			*start = folio_next_index(folio);
 	}
 out:
 	rcu_read_unlock();
@@ -2364,7 +2355,7 @@ static void filemap_get_read_batch(struct address_space *mapping,
 			break;
 		if (folio_test_readahead(folio))
 			break;
-		xas_advance(&xas, folio->index + folio_nr_pages(folio) - 1);
+		xas_advance(&xas, folio_next_index(folio) - 1);
 		continue;
 put_folio:
 		folio_put(folio);
@@ -2637,6 +2628,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
 	int i, error = 0;
 	bool writably_mapped;
 	loff_t isize, end_offset;
+	loff_t last_pos = ra->prev_pos;
 
 	if (unlikely(iocb->ki_pos >= inode->i_sb->s_maxbytes))
 		return 0;
@@ -2687,8 +2679,8 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
 		 * When a read accesses the same folio several times, only
 		 * mark it as accessed the first time.
 		 */
-		if (!pos_same_folio(iocb->ki_pos, ra->prev_pos - 1,
-							fbatch.folios[0]))
+		if (!pos_same_folio(iocb->ki_pos, last_pos - 1,
+				    fbatch.folios[0]))
 			folio_mark_accessed(fbatch.folios[0]);
 
 		for (i = 0; i < folio_batch_count(&fbatch); i++) {
@@ -2715,7 +2707,7 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
 
 			already_read += copied;
 			iocb->ki_pos += copied;
-			ra->prev_pos = iocb->ki_pos;
+			last_pos = iocb->ki_pos;
 
 			if (copied < bytes) {
 				error = -EFAULT;
@@ -2729,7 +2721,7 @@ put_folios:
 	} while (iov_iter_count(iter) && iocb->ki_pos < isize && !error);
 
 	file_accessed(filp);
-
+	ra->prev_pos = last_pos;
 	return already_read ? already_read : error;
 }
 EXPORT_SYMBOL_GPL(filemap_read);
@@ -3439,10 +3431,10 @@ static bool filemap_map_pmd(struct vm_fault *vmf, struct folio *folio,
 	return false;
 }
 
-static struct folio *next_uptodate_page(struct folio *folio,
-				       struct address_space *mapping,
-				       struct xa_state *xas, pgoff_t end_pgoff)
+static struct folio *next_uptodate_folio(struct xa_state *xas,
+		struct address_space *mapping, pgoff_t end_pgoff)
 {
+	struct folio *folio = xas_next_entry(xas, end_pgoff);
 	unsigned long max_idx;
 
 	do {
@@ -3480,20 +3472,65 @@ skip:
 	return NULL;
 }
 
-static inline struct folio *first_map_page(struct address_space *mapping,
-					  struct xa_state *xas,
-					  pgoff_t end_pgoff)
+/*
+ * Map page range [start_page, start_page + nr_pages) of folio.
+ * start_page is gotten from start by folio_page(folio, start)
+ */
+static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
+			struct folio *folio, unsigned long start,
+			unsigned long addr, unsigned int nr_pages)
 {
-	return next_uptodate_page(xas_find(xas, end_pgoff),
-				  mapping, xas, end_pgoff);
-}
+	vm_fault_t ret = 0;
+	struct vm_area_struct *vma = vmf->vma;
+	struct file *file = vma->vm_file;
+	struct page *page = folio_page(folio, start);
+	unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss);
+	unsigned int count = 0;
+	pte_t *old_ptep = vmf->pte;
 
-static inline struct folio *next_map_page(struct address_space *mapping,
-					 struct xa_state *xas,
-					 pgoff_t end_pgoff)
-{
-	return next_uptodate_page(xas_next_entry(xas, end_pgoff),
-				  mapping, xas, end_pgoff);
+	do {
+		if (PageHWPoison(page + count))
+			goto skip;
+
+		if (mmap_miss > 0)
+			mmap_miss--;
+
+		/*
+		 * NOTE: If there're PTE markers, we'll leave them to be
+		 * handled in the specific fault path, and it'll prohibit the
+		 * fault-around logic.
+		 */
+		if (!pte_none(vmf->pte[count]))
+			goto skip;
+
+		count++;
+		continue;
+skip:
+		if (count) {
+			set_pte_range(vmf, folio, page, count, addr);
+			folio_ref_add(folio, count);
+			if (in_range(vmf->address, addr, count))
+				ret = VM_FAULT_NOPAGE;
+		}
+
+		count++;
+		page += count;
+		vmf->pte += count;
+		addr += count * PAGE_SIZE;
+		count = 0;
+	} while (--nr_pages > 0);
+
+	if (count) {
+		set_pte_range(vmf, folio, page, count, addr);
+		folio_ref_add(folio, count);
+		if (in_range(vmf->address, addr, count))
+			ret = VM_FAULT_NOPAGE;
+	}
+
+	vmf->pte = old_ptep;
+	WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss);
+
+	return ret;
 }
 
 vm_fault_t filemap_map_pages(struct vm_fault *vmf,
@@ -3506,12 +3543,11 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
 	unsigned long addr;
 	XA_STATE(xas, &mapping->i_pages, start_pgoff);
 	struct folio *folio;
-	struct page *page;
-	unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss);
 	vm_fault_t ret = 0;
+	int nr_pages = 0;
 
 	rcu_read_lock();
-	folio = first_map_page(mapping, &xas, end_pgoff);
+	folio = next_uptodate_folio(&xas, mapping, end_pgoff);
 	if (!folio)
 		goto out;
 
@@ -3528,17 +3564,13 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
 		goto out;
 	}
 	do {
-again:
-		page = folio_file_page(folio, xas.xa_index);
-		if (PageHWPoison(page))
-			goto unlock;
-
-		if (mmap_miss > 0)
-			mmap_miss--;
+		unsigned long end;
 
 		addr += (xas.xa_index - last_pgoff) << PAGE_SHIFT;
 		vmf->pte += xas.xa_index - last_pgoff;
 		last_pgoff = xas.xa_index;
+		end = folio->index + folio_nr_pages(folio) - 1;
+		nr_pages = min(end, end_pgoff) - xas.xa_index + 1;
 
 		/*
 		 * NOTE: If there're PTE markers, we'll leave them to be
@@ -3548,32 +3580,17 @@ again:
 		if (!pte_none(ptep_get(vmf->pte)))
 			goto unlock;
 
-		/* We're about to handle the fault */
-		if (vmf->address == addr)
-			ret = VM_FAULT_NOPAGE;
+		ret |= filemap_map_folio_range(vmf, folio,
+				xas.xa_index - folio->index, addr, nr_pages);
 
-		do_set_pte(vmf, page, addr);
-		/* no need to invalidate: a not-present page won't be cached */
-		update_mmu_cache(vma, addr, vmf->pte);
-		if (folio_more_pages(folio, xas.xa_index, end_pgoff)) {
-			xas.xa_index++;
-			folio_ref_inc(folio);
-			goto again;
-		}
-		folio_unlock(folio);
-		continue;
 unlock:
-		if (folio_more_pages(folio, xas.xa_index, end_pgoff)) {
-			xas.xa_index++;
-			goto again;
-		}
 		folio_unlock(folio);
 		folio_put(folio);
-	} while ((folio = next_map_page(mapping, &xas, end_pgoff)) != NULL);
+		folio = next_uptodate_folio(&xas, mapping, end_pgoff);
+	} while (folio);
 	pte_unmap_unlock(vmf->pte, vmf->ptl);
 out:
 	rcu_read_unlock();
-	WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss);
 	return ret;
 }
 EXPORT_SYMBOL(filemap_map_pages);
@@ -4077,6 +4094,8 @@ bool filemap_release_folio(struct folio *folio, gfp_t gfp)
 	struct address_space * const mapping = folio->mapping;
 
 	BUG_ON(!folio_test_locked(folio));
+	if (!folio_needs_release(folio))
+		return true;
 	if (folio_test_writeback(folio))
 		return false;