mm/filemap: Pass the file_ra_state in the ractl

For readahead_expand(), we need to modify the file ra_state, so pass it
down by adding it to the ractl.  We have to do this because it's not always
the same as f_ra in the struct file that is already being passed.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
Link: https://lore.kernel.org/r/20210407201857.3582797-2-willy@infradead.org/
Link: https://lore.kernel.org/r/161789067431.6155.8063840447229665720.stgit@warthog.procyon.org.uk/ # v6

Author: Matthew Wilcox (Oracle)

fs/ext4/verity.c

@@ -370,7 +370,7 @@ static struct page *ext4_read_merkle_tree_page(struct inode *inode,
 					       pgoff_t index,
 					       unsigned long num_ra_pages)
 {
-	DEFINE_READAHEAD(ractl, NULL, inode->i_mapping, index);
+	DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
 	struct page *page;
 
 	index += ext4_verity_metadata_pos(inode) >> PAGE_SHIFT;

fs/f2fs/file.c

@@ -4051,7 +4051,7 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg)
 
 static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int len)
 {
-	DEFINE_READAHEAD(ractl, NULL, inode->i_mapping, page_idx);
+	DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, page_idx);
 	struct address_space *mapping = inode->i_mapping;
 	struct page *page;
 	pgoff_t redirty_idx = page_idx;

fs/f2fs/verity.c

@@ -228,7 +228,7 @@ static struct page *f2fs_read_merkle_tree_page(struct inode *inode,
 					       pgoff_t index,
 					       unsigned long num_ra_pages)
 {
-	DEFINE_READAHEAD(ractl, NULL, inode->i_mapping, index);
+	DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
 	struct page *page;
 
 	index += f2fs_verity_metadata_pos(inode) >> PAGE_SHIFT;

include/linux/pagemap.h

@@ -812,31 +812,33 @@ static inline int add_to_page_cache(struct page *page,
  * @file: The file, used primarily by network filesystems for authentication.
  *	  May be NULL if invoked internally by the filesystem.
  * @mapping: Readahead this filesystem object.
+ * @ra: File readahead state.  May be NULL.
  */
 struct readahead_control {
 	struct file *file;
 	struct address_space *mapping;
+	struct file_ra_state *ra;
 /* private: use the readahead_* accessors instead */
 	pgoff_t _index;
 	unsigned int _nr_pages;
 	unsigned int _batch_count;
 };
 
-#define DEFINE_READAHEAD(rac, f, m, i)					\
-	struct readahead_control rac = {				\
+#define DEFINE_READAHEAD(ractl, f, r, m, i)				\
+	struct readahead_control ractl = {				\
 		.file = f,						\
 		.mapping = m,						\
+		.ra = r,						\
 		._index = i,						\
 	}
 
 #define VM_READAHEAD_PAGES	(SZ_128K / PAGE_SIZE)
 
 void page_cache_ra_unbounded(struct readahead_control *,
 		unsigned long nr_to_read, unsigned long lookahead_count);
-void page_cache_sync_ra(struct readahead_control *, struct file_ra_state *,
+void page_cache_sync_ra(struct readahead_control *, unsigned long req_count);
+void page_cache_async_ra(struct readahead_control *, struct page *,
 		unsigned long req_count);
-void page_cache_async_ra(struct readahead_control *, struct file_ra_state *,
-		struct page *, unsigned long req_count);
 
 /**
  * page_cache_sync_readahead - generic file readahead
@@ -856,8 +858,8 @@ void page_cache_sync_readahead(struct address_space *mapping,
 		struct file_ra_state *ra, struct file *file, pgoff_t index,
 		unsigned long req_count)
 {
-	DEFINE_READAHEAD(ractl, file, mapping, index);
-	page_cache_sync_ra(&ractl, ra, req_count);
+	DEFINE_READAHEAD(ractl, file, ra, mapping, index);
+	page_cache_sync_ra(&ractl, req_count);
 }
 
 /**
@@ -879,8 +881,8 @@ void page_cache_async_readahead(struct address_space *mapping,
 		struct file_ra_state *ra, struct file *file,
 		struct page *page, pgoff_t index, unsigned long req_count)
 {
-	DEFINE_READAHEAD(ractl, file, mapping, index);
-	page_cache_async_ra(&ractl, ra, page, req_count);
+	DEFINE_READAHEAD(ractl, file, ra, mapping, index);
+	page_cache_async_ra(&ractl, page, req_count);
 }
 
 /**

mm/filemap.c

@@ -2832,7 +2832,7 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)
 	struct file *file = vmf->vma->vm_file;
 	struct file_ra_state *ra = &file->f_ra;
 	struct address_space *mapping = file->f_mapping;
-	DEFINE_READAHEAD(ractl, file, mapping, vmf->pgoff);
+	DEFINE_READAHEAD(ractl, file, ra, mapping, vmf->pgoff);
 	struct file *fpin = NULL;
 	unsigned int mmap_miss;
 
@@ -2844,7 +2844,7 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)
 
 	if (vmf->vma->vm_flags & VM_SEQ_READ) {
 		fpin = maybe_unlock_mmap_for_io(vmf, fpin);
-		page_cache_sync_ra(&ractl, ra, ra->ra_pages);
+		page_cache_sync_ra(&ractl, ra->ra_pages);
 		return fpin;
 	}
 

mm/internal.h

@@ -51,13 +51,12 @@ void unmap_page_range(struct mmu_gather *tlb,
 
 void do_page_cache_ra(struct readahead_control *, unsigned long nr_to_read,
 		unsigned long lookahead_size);
-void force_page_cache_ra(struct readahead_control *, struct file_ra_state *,
-		unsigned long nr);
+void force_page_cache_ra(struct readahead_control *, unsigned long nr);
 static inline void force_page_cache_readahead(struct address_space *mapping,
 		struct file *file, pgoff_t index, unsigned long nr_to_read)
 {
-	DEFINE_READAHEAD(ractl, file, mapping, index);
-	force_page_cache_ra(&ractl, &file->f_ra, nr_to_read);
+	DEFINE_READAHEAD(ractl, file, &file->f_ra, mapping, index);
+	force_page_cache_ra(&ractl, nr_to_read);
 }
 
 unsigned find_lock_entries(struct address_space *mapping, pgoff_t start,

mm/readahead.c

@@ -272,9 +272,10 @@ void do_page_cache_ra(struct readahead_control *ractl,
  * memory at once.
  */
 void force_page_cache_ra(struct readahead_control *ractl,
-		struct file_ra_state *ra, unsigned long nr_to_read)
+		unsigned long nr_to_read)
 {
 	struct address_space *mapping = ractl->mapping;
+	struct file_ra_state *ra = ractl->ra;
 	struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
 	unsigned long max_pages, index;
 
@@ -433,10 +434,10 @@ static int try_context_readahead(struct address_space *mapping,
  * A minimal readahead algorithm for trivial sequential/random reads.
  */
 static void ondemand_readahead(struct readahead_control *ractl,
-		struct file_ra_state *ra, bool hit_readahead_marker,
-		unsigned long req_size)
+		bool hit_readahead_marker, unsigned long req_size)
 {
 	struct backing_dev_info *bdi = inode_to_bdi(ractl->mapping->host);
+	struct file_ra_state *ra = ractl->ra;
 	unsigned long max_pages = ra->ra_pages;
 	unsigned long add_pages;
 	unsigned long index = readahead_index(ractl);
@@ -550,7 +551,7 @@ static void ondemand_readahead(struct readahead_control *ractl,
 }
 
 void page_cache_sync_ra(struct readahead_control *ractl,
-		struct file_ra_state *ra, unsigned long req_count)
+		unsigned long req_count)
 {
 	bool do_forced_ra = ractl->file && (ractl->file->f_mode & FMODE_RANDOM);
 
@@ -560,7 +561,7 @@ void page_cache_sync_ra(struct readahead_control *ractl,
 	 * read-ahead will do the right thing and limit the read to just the
 	 * requested range, which we'll set to 1 page for this case.
 	 */
-	if (!ra->ra_pages || blk_cgroup_congested()) {
+	if (!ractl->ra->ra_pages || blk_cgroup_congested()) {
 		if (!ractl->file)
 			return;
 		req_count = 1;
@@ -569,21 +570,20 @@ void page_cache_sync_ra(struct readahead_control *ractl,
 
 	/* be dumb */
 	if (do_forced_ra) {
-		force_page_cache_ra(ractl, ra, req_count);
+		force_page_cache_ra(ractl, req_count);
 		return;
 	}
 
 	/* do read-ahead */
-	ondemand_readahead(ractl, ra, false, req_count);
+	ondemand_readahead(ractl, false, req_count);
 }
 EXPORT_SYMBOL_GPL(page_cache_sync_ra);
 
 void page_cache_async_ra(struct readahead_control *ractl,
-		struct file_ra_state *ra, struct page *page,
-		unsigned long req_count)
+		struct page *page, unsigned long req_count)
 {
 	/* no read-ahead */
-	if (!ra->ra_pages)
+	if (!ractl->ra->ra_pages)
 		return;
 
 	/*
@@ -604,7 +604,7 @@ void page_cache_async_ra(struct readahead_control *ractl,
 		return;
 
 	/* do read-ahead */
-	ondemand_readahead(ractl, ra, true, req_count);
+	ondemand_readahead(ractl, true, req_count);
 }
 EXPORT_SYMBOL_GPL(page_cache_async_ra);