[PATCH] checkpoint: discard const from struct cred * where appropriate

[Nathan Lynch <ntl-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>]

Building the checkpoint tree results in enough build noise that
it's getting easy to miss new warnings added during development:

kernel/cred.c:737: warning: passing argument 2 of 'checkpoint_capabilities' discards qualifiers from pointer target type
checkpoint/process.c:146: warning: assignment discards qualifiers from pointer target type
checkpoint/process.c:147: warning: assignment discards qualifiers from pointer target type
checkpoint/files.c:154: warning: passing argument 2 of 'checkpoint_obj' discards qualifiers from pointer target type

The objhash code would require significant modification to properly
handle const objects, and only struct cred * is causing this kind of
warning, so just insert casts or drop const where it makes sense.

Signed-off-by: Nathan Lynch <ntl-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
---
 checkpoint/files.c   |    4 +++-
 checkpoint/process.c |    4 ++--
 kernel/cred.c        |    2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/checkpoint/files.c b/checkpoint/files.c
index 204055b..8f90c16 100644
--- a/checkpoint/files.c
+++ b/checkpoint/files.c
@@ -146,12 +146,14 @@ static int scan_fds(struct files_struct *files, int **fdtable)
 int checkpoint_file_common(struct ckpt_ctx *ctx, struct file *file,
 			   struct ckpt_hdr_file *h)
 {
+	struct cred *f_cred = (struct cred *)file->f_cred;
+
 	h->f_flags = file->f_flags;
 	h->f_mode = file->f_mode;
 	h->f_pos = file->f_pos;
 	h->f_version = file->f_version;
 
-	h->f_credref = checkpoint_obj(ctx, file->f_cred, CKPT_OBJ_CRED);
+	h->f_credref = checkpoint_obj(ctx, f_cred, CKPT_OBJ_CRED);
 	if (h->f_credref < 0)
 		return h->f_credref;
 
diff --git a/checkpoint/process.c b/checkpoint/process.c
index 40b2580..41566db 100644
--- a/checkpoint/process.c
+++ b/checkpoint/process.c
@@ -143,8 +143,8 @@ static int checkpoint_task_creds(struct ckpt_ctx *ctx, struct task_struct *t)
 	struct ckpt_hdr_task_creds *h;
 	int ret;
 
-	rcred = get_cred(t->real_cred);
-	ecred = get_cred(t->cred);
+	rcred = (struct cred *)get_cred(t->real_cred);
+	ecred = (struct cred *)get_cred(t->cred);
 
 	realcred_ref = checkpoint_obj(ctx, rcred, CKPT_OBJ_CRED);
 	if (realcred_ref < 0) {
diff --git a/kernel/cred.c b/kernel/cred.c
index 27e02ca..9710cae 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -706,7 +706,7 @@ int cred_setfsgid(struct cred *new, gid_t gid, gid_t *old_fsgid)
 }
 
 #ifdef CONFIG_CHECKPOINT
-static int do_checkpoint_cred(struct ckpt_ctx *ctx, const struct cred *cred)
+static int do_checkpoint_cred(struct ckpt_ctx *ctx, struct cred *cred)
 {
 	int ret;
 	int groupinfo_ref, user_ref;
-- 
1.6.0.6