mm/readahead: make ondemand_readahead take a readahead_control

Make ondemand_readahead() take a readahead_control struct in preparation
for making do_sync_mmap_readahead() pass down an RAC struct.

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/20200903140844.14194-6-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/readahead.c b/mm/readahead.c
index 577f180d92521ed113e8fca3035a3a112f5af433..73110c4148f81dda8a9cfba19f310a5fd498b72c 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -431,15 +431,14 @@ static int try_context_readahead(struct address_space *mapping,
 /*
  * A minimal readahead algorithm for trivial sequential/random reads.
  */
-static void ondemand_readahead(struct address_space *mapping,
-               struct file_ra_state *ra, struct file *file,
-               bool hit_readahead_marker, pgoff_t index,
+static void ondemand_readahead(struct readahead_control *ractl,
+               struct file_ra_state *ra, bool hit_readahead_marker,
                unsigned long req_size)
 {
-       DEFINE_READAHEAD(ractl, file, mapping, index);
-       struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
+       struct backing_dev_info *bdi = inode_to_bdi(ractl->mapping->host);
        unsigned long max_pages = ra->ra_pages;
        unsigned long add_pages;
+       unsigned long index = readahead_index(ractl);
        pgoff_t prev_index;
 
        /*
@@ -477,7 +476,8 @@ static void ondemand_readahead(struct address_space *mapping,
                pgoff_t start;
 
                rcu_read_lock();
-               start = page_cache_next_miss(mapping, index + 1, max_pages);
+               start = page_cache_next_miss(ractl->mapping, index + 1,
+                               max_pages);
                rcu_read_unlock();
 
                if (!start || start - index > max_pages)
@@ -510,14 +510,15 @@ static void ondemand_readahead(struct address_space *mapping,
         * Query the page cache and look for the traces(cached history pages)
         * that a sequential stream would leave behind.
         */
-       if (try_context_readahead(mapping, ra, index, req_size, max_pages))
+       if (try_context_readahead(ractl->mapping, ra, index, req_size,
+                       max_pages))
                goto readit;
 
        /*
         * standalone, small random read
         * Read as is, and do not pollute the readahead state.
         */
-       do_page_cache_ra(&ractl, req_size, 0);
+       do_page_cache_ra(ractl, req_size, 0);
        return;
 
 initial_readahead:
@@ -543,8 +544,8 @@ readit:
                }
        }
 
-       ractl._index = ra->start;
-       do_page_cache_ra(&ractl, ra->size, ra->async_size);
+       ractl->_index = ra->start;
+       do_page_cache_ra(ractl, ra->size, ra->async_size);
 }
 
 /**
@@ -564,6 +565,8 @@ void page_cache_sync_readahead(struct address_space *mapping,
                               struct file_ra_state *ra, struct file *filp,
                               pgoff_t index, unsigned long req_count)
 {
+       DEFINE_READAHEAD(ractl, filp, mapping, index);
+
        /* no read-ahead */
        if (!ra->ra_pages)
                return;
@@ -578,7 +581,7 @@ void page_cache_sync_readahead(struct address_space *mapping,
        }
 
        /* do read-ahead */
-       ondemand_readahead(mapping, ra, filp, false, index, req_count);
+       ondemand_readahead(&ractl, ra, false, req_count);
 }
 EXPORT_SYMBOL_GPL(page_cache_sync_readahead);
 
@@ -602,6 +605,8 @@ page_cache_async_readahead(struct address_space *mapping,
                           struct page *page, pgoff_t index,
                           unsigned long req_count)
 {
+       DEFINE_READAHEAD(ractl, filp, mapping, index);
+
        /* no read-ahead */
        if (!ra->ra_pages)
                return;
@@ -624,7 +629,7 @@ page_cache_async_readahead(struct address_space *mapping,
                return;
 
        /* do read-ahead */
-       ondemand_readahead(mapping, ra, filp, true, index, req_count);
+       ondemand_readahead(&ractl, ra, true, req_count);
 }
 EXPORT_SYMBOL_GPL(page_cache_async_readahead);