replace ->follow_link() with new method that could stay in RCU mode
new method: ->get_link(); replacement of ->follow_link(). The differences
are:
* inode and dentry are passed separately
* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.
It's a flagday change - the old method is gone, all in-tree instances
converted. Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode. That'll change
in the next commits.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/shmem.c b/mm/shmem.c
index 64bf5ac..684dbc3 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2496,10 +2496,14 @@
return 0;
}
-static const char *shmem_follow_link(struct dentry *dentry, void **cookie)
+static const char *shmem_get_link(struct dentry *dentry,
+ struct inode *inode, void **cookie)
{
struct page *page = NULL;
- int error = shmem_getpage(d_inode(dentry), 0, &page, SGP_READ, NULL);
+ int error;
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+ error = shmem_getpage(inode, 0, &page, SGP_READ, NULL);
if (error)
return ERR_PTR(error);
unlock_page(page);
@@ -2656,7 +2660,7 @@
static const struct inode_operations shmem_short_symlink_operations = {
.readlink = generic_readlink,
- .follow_link = simple_follow_link,
+ .get_link = simple_get_link,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
@@ -2667,7 +2671,7 @@
static const struct inode_operations shmem_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = shmem_follow_link,
+ .get_link = shmem_get_link,
.put_link = shmem_put_link,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,