Merge branch 'develop' of 10.10.10.29:/home/rockchip/kernel into develop

[firefly-linux-kernel-4.4.55.git] / mm / readahead.c

diff --git a/mm/readahead.c b/mm/readahead.c
index aa1aa23452355067af9d62179cd41d62c64e68fc..fe1a069fb59571488af927b54abce0e9f56fd88e 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -501,6 +501,12 @@ void page_cache_sync_readahead(struct address_space *mapping,
        if (!ra->ra_pages)
                return;
 
+       /* be dumb */
+       if (filp && (filp->f_mode & FMODE_RANDOM)) {
+               force_page_cache_readahead(mapping, filp, offset, req_size);
+               return;
+       }
+
        /* do read-ahead */
        ondemand_readahead(mapping, ra, filp, false, offset, req_size);
 }
@@ -547,5 +553,17 @@ page_cache_async_readahead(struct address_space *mapping,
 
        /* do read-ahead */
        ondemand_readahead(mapping, ra, filp, true, offset, req_size);
+
+#ifdef CONFIG_BLOCK
+       /*
+        * Normally the current page is !uptodate and lock_page() will be
+        * immediately called to implicitly unplug the device. However this
+        * is not always true for RAID conifgurations, where data arrives
+        * not strictly in their submission order. In this case we need to
+        * explicitly kick off the IO.
+        */
+       if (PageUptodate(page))
+               blk_run_backing_dev(mapping->backing_dev_info, NULL);
+#endif
 }
 EXPORT_SYMBOL_GPL(page_cache_async_readahead);