mm/readahead: pass readahead_control to force_page_cache_ra

Reimplement force_page_cache_readahead() as a wrapper around
force_page_cache_ra().  Pass the existing readahead_control from
page_cache_sync_readahead().

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-7-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/internal.h b/mm/internal.h
index 41ade6c..059ad01 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -49,10 +49,15 @@ void unmap_page_range(struct mmu_gather *tlb,
                             unsigned long addr, unsigned long end,
                             struct zap_details *details);
 
-void force_page_cache_readahead(struct address_space *, struct file *,
-               pgoff_t index, unsigned long nr_to_read);
-void do_page_cache_ra(struct readahead_control *,
-               unsigned long nr_to_read, unsigned long lookahead_size);
+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 *, 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, nr_to_read);
+}
 
 /*
  * Submit IO for the read-ahead request in file_ra_state.

diff --git a/mm/readahead.c b/mm/readahead.c
index 73110c4..3115ced 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -271,13 +271,13 @@ void do_page_cache_ra(struct readahead_control *ractl,
  * Chunk the readahead into 2 megabyte units, so that we don't pin too much
  * memory at once.
  */
-void force_page_cache_readahead(struct address_space *mapping,
-               struct file *file, pgoff_t index, unsigned long nr_to_read)
+void force_page_cache_ra(struct readahead_control *ractl,
+               unsigned long nr_to_read)
 {
-       DEFINE_READAHEAD(ractl, file, mapping, index);
+       struct address_space *mapping = ractl->mapping;
        struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
-       struct file_ra_state *ra = &file->f_ra;
-       unsigned long max_pages;
+       struct file_ra_state *ra = &ractl->file->f_ra;
+       unsigned long max_pages, index;
 
        if (unlikely(!mapping->a_ops->readpage && !mapping->a_ops->readpages &&
                        !mapping->a_ops->readahead))
@@ -287,14 +287,16 @@ void force_page_cache_readahead(struct address_space *mapping,
         * If the request exceeds the readahead window, allow the read to
         * be up to the optimal hardware IO size
         */
+       index = readahead_index(ractl);
        max_pages = max_t(unsigned long, bdi->io_pages, ra->ra_pages);
-       nr_to_read = min(nr_to_read, max_pages);
+       nr_to_read = min_t(unsigned long, nr_to_read, max_pages);
        while (nr_to_read) {
                unsigned long this_chunk = (2 * 1024 * 1024) / PAGE_SIZE;
 
                if (this_chunk > nr_to_read)
                        this_chunk = nr_to_read;
-               do_page_cache_ra(&ractl, this_chunk, 0);
+               ractl->_index = index;
+               do_page_cache_ra(ractl, this_chunk, 0);
 
                index += this_chunk;
                nr_to_read -= this_chunk;
@@ -576,7 +578,7 @@ void page_cache_sync_readahead(struct address_space *mapping,
 
        /* be dumb */
        if (filp && (filp->f_mode & FMODE_RANDOM)) {
-               force_page_cache_readahead(mapping, filp, index, req_count);
+               force_page_cache_ra(&ractl, req_count);
                return;
        }