fs: afs: revert mmap_prepare() change

Partially reverts commit 9d5403b1036c ("fs: convert most other
generic_file_*mmap() users to .mmap_prepare()").

This is because the .mmap invocation establishes a refcount, but
.mmap_prepare is called at a point where a merge or an allocation failure
might happen after the call, which would leak the refcount increment.

Functionality is being added to permit the use of .mmap_prepare in this
case, but in the interim, we need to fix this.

Link: https://lkml.kernel.org/r/08804c94e39d9102a3a8fbd12385e8aa079ba1d3.1774045440.git.ljs@kernel.org
Fixes: 9d5403b1036c ("fs: convert most other generic_file_*mmap() users to .mmap_prepare()")
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bodo Stroesser <bostroesser@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: David Hildenbrand <david@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Long Li <longli@microsoft.com>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Richard Weinberger <richard@nod.at>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/afs/file.c b/fs/afs/file.c
index f609366fd2ac076c7a3f1437997622a7df6ea0eb..74d04af51ff4ae80e626d897aeb266751db70573 100644 (file)
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -19,7 +19,7 @@
 #include <trace/events/netfs.h>
 #include "internal.h"
 
-static int afs_file_mmap_prepare(struct vm_area_desc *desc);
+static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
 
 static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
 static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
@@ -35,7 +35,7 @@ const struct file_operations afs_file_operations = {
        .llseek         = generic_file_llseek,
        .read_iter      = afs_file_read_iter,
        .write_iter     = netfs_file_write_iter,
-       .mmap_prepare   = afs_file_mmap_prepare,
+       .mmap           = afs_file_mmap,
        .splice_read    = afs_file_splice_read,
        .splice_write   = iter_file_splice_write,
        .fsync          = afs_fsync,
@@ -492,16 +492,16 @@ static void afs_drop_open_mmap(struct afs_vnode *vnode)
 /*
  * Handle setting up a memory mapping on an AFS file.
  */
-static int afs_file_mmap_prepare(struct vm_area_desc *desc)
+static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
-       struct afs_vnode *vnode = AFS_FS_I(file_inode(desc->file));
+       struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
        int ret;
 
        afs_add_open_mmap(vnode);
 
-       ret = generic_file_mmap_prepare(desc);
+       ret = generic_file_mmap(file, vma);
        if (ret == 0)
-               desc->vm_ops = &afs_vm_ops;
+               vma->vm_ops = &afs_vm_ops;
        else
                afs_drop_open_mmap(vnode);
        return ret;