Use lock_page_killable

Replacing lock_page with lock_page_killable in do_generic_mapping_read()
allows us to kill `cat' of a file on an NFS-mounted filesystem

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index ac8f690d2885..455119cc7f40 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -982,7 +982,8 @@ page_ok:
 
 page_not_up_to_date:
                 /* Get exclusive access to the page ... */
-                lock_page(page);
+                if (lock_page_killable(page))
+                        goto readpage_eio;
 
                 /* Did it get truncated before we got the lock? */
                 if (!page->mapping) {
@@ -1010,7 +1011,8 @@ readpage:
                 }
 
                 if (!PageUptodate(page)) {
-                        lock_page(page);
+                        if (lock_page_killable(page))
+                                goto readpage_eio;
                         if (!PageUptodate(page)) {
                                 if (page->mapping == NULL) {
                                         /*
@@ -1021,15 +1023,16 @@ readpage:
                                         goto find_page;
                                 }
                                 unlock_page(page);
-                                error = -EIO;
                                 shrink_readahead_size_eio(filp, ra);
-                                goto readpage_error;
+                                goto readpage_eio;
                         }
                         unlock_page(page);
                 }
 
                 goto page_ok;
 
+readpage_eio:
+                error = -EIO;
 readpage_error:
                 /* UHHUH! A synchronous read error occurred. Report it */
                 desc->error = error;