Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[mirror_ubuntu-focal-kernel.git] / mm / readahead.c

diff --git a/mm/readahead.c b/mm/readahead.c
index a59ea70527b9bc46b4fde403a7f19b93493351fb..4e630143a0ba8549c9a63f106c7dd18b7aaa4d18 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -20,6 +20,7 @@
 #include <linux/file.h>
 #include <linux/mm_inline.h>
 #include <linux/blk-cgroup.h>
+#include <linux/fadvise.h>
 
 #include "internal.h"
 
@@ -575,24 +576,6 @@ page_cache_async_readahead(struct address_space *mapping,
 }
 EXPORT_SYMBOL_GPL(page_cache_async_readahead);
 
-static ssize_t
-do_readahead(struct address_space *mapping, struct file *filp,
-            pgoff_t index, unsigned long nr)
-{
-       if (!mapping || !mapping->a_ops)
-               return -EINVAL;
-
-       /*
-        * Readahead doesn't make sense for DAX inodes, but we don't want it
-        * to report a failure either.  Instead, we just return success and
-        * don't do any work.
-        */
-       if (dax_mapping(mapping))
-               return 0;
-
-       return force_page_cache_readahead(mapping, filp, index, nr);
-}
-
 ssize_t ksys_readahead(int fd, loff_t offset, size_t count)
 {
        ssize_t ret;
@@ -600,16 +583,22 @@ ssize_t ksys_readahead(int fd, loff_t offset, size_t count)
 
        ret = -EBADF;
        f = fdget(fd);
-       if (f.file) {
-               if (f.file->f_mode & FMODE_READ) {
-                       struct address_space *mapping = f.file->f_mapping;
-                       pgoff_t start = offset >> PAGE_SHIFT;
-                       pgoff_t end = (offset + count - 1) >> PAGE_SHIFT;
-                       unsigned long len = end - start + 1;
-                       ret = do_readahead(mapping, f.file, start, len);
-               }
-               fdput(f);
-       }
+       if (!f.file || !(f.file->f_mode & FMODE_READ))
+               goto out;
+
+       /*
+        * The readahead() syscall is intended to run only on files
+        * that can execute readahead. If readahead is not possible
+        * on this file, then we must return -EINVAL.
+        */
+       ret = -EINVAL;
+       if (!f.file->f_mapping || !f.file->f_mapping->a_ops ||
+           !S_ISREG(file_inode(f.file)->i_mode))
+               goto out;
+
+       ret = vfs_fadvise(f.file, offset, count, POSIX_FADV_WILLNEED);
+out:
+       fdput(f);
        return ret;
 }