Replace kref_t by a simple refcount. We do not care about the atomicity of the operation as long as the mutex is held. This fixes a false-positive memory leak warning from kref_put() where we close the cached fid twice and make the kref underflow. Link: https://lore.kernel.org/linux-cifs/20190319115151.GA2092@xxxxxxxxxxxxxxxxxxxxxxxxxx/ Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx> --- fs/cifs/cifsglob.h | 2 +- fs/cifs/smb2ops.c | 34 ++++++++++++++-------------------- 2 files changed, 15 insertions(+), 21 deletions(-) diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 38feae812b47..256cd48fb4c7 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -972,7 +972,7 @@ struct cached_fid { bool is_valid:1; /* Do we have a useable root fid */ bool file_all_info_is_valid:1; - struct kref refcount; + refcount_t refcount; struct cifs_fid *fid; struct mutex fid_mutex; struct cifs_tcon *tcon; diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 1022a3771e14..062c081a298c 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -608,25 +608,21 @@ SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon) return rc; } -static void -smb2_close_cached_fid(struct kref *ref) -{ - struct cached_fid *cfid = container_of(ref, struct cached_fid, - refcount); - - if (cfid->is_valid) { - cifs_dbg(FYI, "clear cached root file handle\n"); - SMB2_close(0, cfid->tcon, cfid->fid->persistent_fid, - cfid->fid->volatile_fid); - cfid->is_valid = false; - cfid->file_all_info_is_valid = false; - } -} - void close_shroot(struct cached_fid *cfid) { + unsigned int n; mutex_lock(&cfid->fid_mutex); - kref_put(&cfid->refcount, smb2_close_cached_fid); + n = refcount_read(&cfid->refcount); + if (n > 0) { + refcount_dec(&cfid->refcount); + if (n == 1 && cfid->is_valid) { + cifs_dbg(FYI, "clear cached root file handle\n"); + SMB2_close(0, cfid->tcon, cfid->fid->persistent_fid, + cfid->fid->volatile_fid); + cfid->is_valid = false; + cfid->file_all_info_is_valid = false; + } + } mutex_unlock(&cfid->fid_mutex); } @@ -662,7 +658,7 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid) if (tcon->crfid.is_valid) { cifs_dbg(FYI, "found a cached root file handle\n"); memcpy(pfid, tcon->crfid.fid, sizeof(struct cifs_fid)); - kref_get(&tcon->crfid.refcount); + refcount_inc(&tcon->crfid.refcount); mutex_unlock(&tcon->crfid.fid_mutex); return 0; } @@ -728,9 +724,7 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid) memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid)); tcon->crfid.tcon = tcon; tcon->crfid.is_valid = true; - kref_init(&tcon->crfid.refcount); - kref_get(&tcon->crfid.refcount); - + refcount_set(&tcon->crfid.refcount, 1); qi_rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base; if (le32_to_cpu(qi_rsp->OutputBufferLength) < sizeof(struct smb2_file_all_info)) -- 2.16.4
