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-rw-r--r--mm/fadvise.c4
-rw-r--r--mm/madvise.c22
2 files changed, 18 insertions, 8 deletions
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 467bcd032037..4f17c83db575 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -27,8 +27,7 @@
* deactivate the pages and clear PG_Referenced.
*/
-static int generic_fadvise(struct file *file, loff_t offset, loff_t len,
- int advice)
+int generic_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
{
struct inode *inode;
struct address_space *mapping;
@@ -178,6 +177,7 @@ static int generic_fadvise(struct file *file, loff_t offset, loff_t len,
}
return 0;
}
+EXPORT_SYMBOL(generic_fadvise);
int vfs_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
{
diff --git a/mm/madvise.c b/mm/madvise.c
index 968df3aa069f..bac973b9f2cc 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -14,6 +14,7 @@
#include <linux/userfaultfd_k.h>
#include <linux/hugetlb.h>
#include <linux/falloc.h>
+#include <linux/fadvise.h>
#include <linux/sched.h>
#include <linux/ksm.h>
#include <linux/fs.h>
@@ -275,6 +276,7 @@ static long madvise_willneed(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
struct file *file = vma->vm_file;
+ loff_t offset;
*prev = vma;
#ifdef CONFIG_SWAP
@@ -298,12 +300,20 @@ static long madvise_willneed(struct vm_area_struct *vma,
return 0;
}
- start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
- if (end > vma->vm_end)
- end = vma->vm_end;
- end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
-
- force_page_cache_readahead(file->f_mapping, file, start, end - start);
+ /*
+ * Filesystem's fadvise may need to take various locks. We need to
+ * explicitly grab a reference because the vma (and hence the
+ * vma's reference to the file) can go away as soon as we drop
+ * mmap_sem.
+ */
+ *prev = NULL; /* tell sys_madvise we drop mmap_sem */
+ get_file(file);
+ up_read(&current->mm->mmap_sem);
+ offset = (loff_t)(start - vma->vm_start)
+ + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+ vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED);
+ fput(file);
+ down_read(&current->mm->mmap_sem);
return 0;
}
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