Add lock_page_killable
This routine is like lock_page, but can be interrupted by a fatal signal
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index db8a410..4b62a10 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -157,6 +157,7 @@
}
extern void FASTCALL(__lock_page(struct page *page));
+extern int FASTCALL(__lock_page_killable(struct page *page));
extern void FASTCALL(__lock_page_nosync(struct page *page));
extern void FASTCALL(unlock_page(struct page *page));
@@ -171,6 +172,19 @@
}
/*
+ * lock_page_killable is like lock_page but can be interrupted by fatal
+ * signals. It returns 0 if it locked the page and -EINTR if it was
+ * killed while waiting.
+ */
+static inline int lock_page_killable(struct page *page)
+{
+ might_sleep();
+ if (TestSetPageLocked(page))
+ return __lock_page_killable(page);
+ return 0;
+}
+
+/*
* lock_page_nosync should only be used if we can't pin the page's inode.
* Doesn't play quite so well with block device plugging.
*/
diff --git a/mm/filemap.c b/mm/filemap.c
index 188cf5f..ac8f690 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -173,6 +173,12 @@
return 0;
}
+static int sync_page_killable(void *word)
+{
+ sync_page(word);
+ return fatal_signal_pending(current) ? -EINTR : 0;
+}
+
/**
* __filemap_fdatawrite_range - start writeback on mapping dirty pages in range
* @mapping: address space structure to write
@@ -577,6 +583,14 @@
}
EXPORT_SYMBOL(__lock_page);
+int fastcall __lock_page_killable(struct page *page)
+{
+ DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+
+ return __wait_on_bit_lock(page_waitqueue(page), &wait,
+ sync_page_killable, TASK_KILLABLE);
+}
+
/*
* Variant of lock_page that does not require the caller to hold a reference
* on the page's mapping.