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functionfs: switch to simple_remove_by_name() 

No need to return dentry from ffs_sb_create_file() or keep it around
afterwards.

To avoid subtle issues with getting to ffs from epfiles in
ffs_epfiles_destroy(), pass the superblock as explicit argument.
Callers have it anyway.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2025-09-17 22:55:33 -04:00
parent e5bf5ee266
commit c7747fafab
1 changed files with 22 additions and 29 deletions
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51
drivers/usb/gadget/function/f_fs.c
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@ -160,8 +160,6 @@ struct ffs_epfile {
struct ffs_data *ffs;
struct ffs_ep *ep; /* P: ffs->eps_lock */
struct dentry *dentry;
/*
* Buffer for holding data from partial reads which may happen since
* we’re rounding user read requests to a multiple of a max packet size.
@ -271,11 +269,11 @@ struct ffs_desc_helper {
};
static int __must_check ffs_epfiles_create(struct ffs_data *ffs);
static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
static void ffs_epfiles_destroy(struct super_block *sb,
struct ffs_epfile *epfiles, unsigned count);
static struct dentry *
ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
const struct file_operations *fops);
static int ffs_sb_create_file(struct super_block *sb, const char *name,
void *data, const struct file_operations *fops);
/* Devices management *******************************************************/
@ -1894,9 +1892,8 @@ ffs_sb_make_inode(struct super_block *sb, void *data,
}
/* Create "regular" file */
static struct dentry *ffs_sb_create_file(struct super_block *sb,
const char *name, void *data,
const struct file_operations *fops)
static int ffs_sb_create_file(struct super_block *sb, const char *name,
void *data, const struct file_operations *fops)
{
struct ffs_data *ffs = sb->s_fs_info;
struct dentry *dentry;
@ -1904,16 +1901,16 @@ static struct dentry *ffs_sb_create_file(struct super_block *sb,
dentry = d_alloc_name(sb->s_root, name);
if (!dentry)
return NULL;
return -ENOMEM;
inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
if (!inode) {
dput(dentry);
return NULL;
return -ENOMEM;
}
d_add(dentry, inode);
return dentry;
return 0;
}
/* Super block */
@ -1956,10 +1953,7 @@ static int ffs_sb_fill(struct super_block *sb, struct fs_context *fc)
return -ENOMEM;
/* EP0 file */
if (!ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations))
return -ENOMEM;
return 0;
return ffs_sb_create_file(sb, "ep0", ffs, &ffs_ep0_operations);
}
enum {
@ -2196,7 +2190,7 @@ static void ffs_data_closed(struct ffs_data *ffs)
flags);
if (epfiles)
ffs_epfiles_destroy(epfiles,
ffs_epfiles_destroy(ffs->sb, epfiles,
ffs->eps_count);
if (ffs->setup_state == FFS_SETUP_PENDING)
@ -2255,7 +2249,7 @@ static void ffs_data_clear(struct ffs_data *ffs)
* copy of epfile will save us from use-after-free.
*/
if (epfiles) {
ffs_epfiles_destroy(epfiles, ffs->eps_count);
ffs_epfiles_destroy(ffs->sb, epfiles, ffs->eps_count);
ffs->epfiles = NULL;
}
@ -2352,6 +2346,7 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
{
struct ffs_epfile *epfile, *epfiles;
unsigned i, count;
int err;
count = ffs->eps_count;
epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
@ -2368,12 +2363,11 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
else
sprintf(epfile->name, "ep%u", i);
epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
epfile,
&ffs_epfile_operations);
if (!epfile->dentry) {
ffs_epfiles_destroy(epfiles, i - 1);
return -ENOMEM;
err = ffs_sb_create_file(ffs->sb, epfile->name,
epfile, &ffs_epfile_operations);
if (err) {
ffs_epfiles_destroy(ffs->sb, epfiles, i - 1);
return err;
}
}
@ -2386,16 +2380,15 @@ static void clear_one(struct dentry *dentry)
smp_store_release(&dentry->d_inode->i_private, NULL);
}
static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
static void ffs_epfiles_destroy(struct super_block *sb,
struct ffs_epfile *epfiles, unsigned count)
{
struct ffs_epfile *epfile = epfiles;
struct dentry *root = sb->s_root;
for (; count; --count, ++epfile) {
BUG_ON(mutex_is_locked(&epfile->mutex));
if (epfile->dentry) {
simple_recursive_removal(epfile->dentry, clear_one);
epfile->dentry = NULL;
}
simple_remove_by_name(root, epfile->name, clear_one);
}
kfree(epfiles);