file->f_ra->ra_pages will remain the initialized value since it opend, which may
be NOT equal to bdi->ra_pages as the latter one is updated somehow(etc,
echo xxx > /sys/block/dm/queue/read_ahead_kb).So sync ra->ra_pages to the
updated value when sync read.
Signed-off-by: Zhaoyang Huang <zhaoyang.hu...@unisoc.com>
---
mm/filemap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/filemap.c b/mm/filemap.c
index d78f577..5c2d7cc 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2470,6 +2470,8 @@ static struct file *do_sync_mmap_readahead(struct
vm_fault *vmf)
struct file *fpin = NULL;
pgoff_t offset = vmf->pgoff;
+ if (ra->ra_pages != inode_to_bdi(mapping->host)->ra_pages)
+ ra->ra_pages = inode_to_bdi(mapping->host)->ra_pages;
/* If we don't want any read-ahead, don't bother */
if (vmf->vma->vm_flags & VM_RAND_READ)
return fpin;
--
1.9.1
