From: Matthew Wilcox <matthew@wil.cx>
Date: Thu, 6 Dec 2007 16:19:57 +0000 (-0500)
Subject: Use lock_page_killable
X-Git-Tag: v2.6.25-rc1~1125^2~7
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=0b94e97a25d9b06ef17fca8da23169200bead1e2;p=linux.git

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 ac8f690d2885..455119cc7f40 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -982,7 +982,8 @@ void do_generic_mapping_read(struct address_space *mapping,
 
 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 @@ void do_generic_mapping_read(struct address_space *mapping,
 		}
 
 		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 @@ void do_generic_mapping_read(struct address_space *mapping,
 					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;