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authorDavid Howells <dhowells@redhat.com>2021-04-26 21:16:16 +0100
committerDavid Howells <dhowells@redhat.com>2021-04-26 23:23:41 +0100
commit53b776c77aca99b663a5512a04abc27670d61058 (patch)
tree8b2144f8c4f1ddf47489c09605b646b03a032b93 /fs/netfs
parent3d14ec1fe61aebe3da85a9b8f2c3d61e43d522e6 (diff)
downloadlinux-53b776c77aca99b663a5512a04abc27670d61058.tar.gz
netfs: Miscellaneous fixes
Fix some miscellaneous things in the new netfs lib[1]:

 (1) The kerneldoc for netfs_readpage() shouldn't say netfs_page().

 (2) netfs_readpage() can get an integer overflow on 32-bit when it
     multiplies page_index(page) by PAGE_SIZE.  It should use
     page_file_offset() instead.

 (3) netfs_write_begin() should use page_offset() to avoid the same
     overflow.

Note that netfs_readpage() needs to use page_file_offset() rather than
page_offset() as it may see swap-over-NFS.

Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/161789062190.6155.12711584466338493050.stgit@warthog.procyon.org.uk/ [1]
Diffstat (limited to 'fs/netfs')
-rw-r--r--fs/netfs/read_helper.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index 1d3b50c5db6d..193841d03de0 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -933,7 +933,7 @@ cleanup:
 EXPORT_SYMBOL(netfs_readahead);
 
 /**
- * netfs_page - Helper to manage a readpage request
+ * netfs_readpage - Helper to manage a readpage request
  * @file: The file to read from
  * @page: The page to read
  * @ops: The network filesystem's operations for the helper to use
@@ -968,7 +968,7 @@ int netfs_readpage(struct file *file,
 		return -ENOMEM;
 	}
 	rreq->mapping	= page_file_mapping(page);
-	rreq->start	= page_index(page) * PAGE_SIZE;
+	rreq->start	= page_file_offset(page);
 	rreq->len	= thp_size(page);
 
 	if (ops->begin_cache_operation) {
@@ -1106,7 +1106,7 @@ retry:
 	if (!rreq)
 		goto error;
 	rreq->mapping		= page->mapping;
-	rreq->start		= page->index * PAGE_SIZE;
+	rreq->start		= page_offset(page);
 	rreq->len		= thp_size(page);
 	rreq->no_unlock_page	= page->index;
 	__set_bit(NETFS_RREQ_NO_UNLOCK_PAGE, &rreq->flags);