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>

diff --git a/mm/filemap.c b/mm/filemap.c
index ac8f690..455119c 100644 (file)
--- 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;