[PATCH v2 2/6] 9p: Change p9_fid_create calling convention

[Matthew Wilcox]

Return NULL instead of ERR_PTR when we can't allocate a FID.  The ENOSPC
return value was getting all the way back to userspace, and that's
confusing for a userspace program which isn't expecting read() to tell it
there's no space left on the filesystem.  The best error we can return to
indicate a temporary failure caused by lack of client resources is ENOMEM.

Maybe it would be better to sleep until a FID is available, but that's
not a change I'm comfortable making.

Signed-off-by: Matthew Wilcox <wi...@infradead.org>
---
 net/9p/client.c | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/net/9p/client.c b/net/9p/client.c
index 999eceb8af98..389a2904b7b3 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -913,13 +913,11 @@ static struct p9_fid *p9_fid_create(struct p9_client 
*clnt)
        p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
        fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
        if (!fid)
-               return ERR_PTR(-ENOMEM);
+               return NULL;
 
        ret = p9_idpool_get(clnt->fidpool);
-       if (ret < 0) {
-               ret = -ENOSPC;
+       if (ret < 0)
                goto error;
-       }
        fid->fid = ret;
 
        memset(&fid->qid, 0, sizeof(struct p9_qid));
@@ -935,7 +933,7 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt)
 
 error:
        kfree(fid);
-       return ERR_PTR(ret);
+       return NULL;
 }
 
 static void p9_fid_destroy(struct p9_fid *fid)
@@ -1137,9 +1135,8 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, 
struct p9_fid *afid,
        p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
                 afid ? afid->fid : -1, uname, aname);
        fid = p9_fid_create(clnt);
-       if (IS_ERR(fid)) {
-               err = PTR_ERR(fid);
-               fid = NULL;
+       if (!fid) {
+               err = -ENOMEM;
                goto error;
        }
        fid->uid = n_uname;
@@ -1188,9 +1185,8 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, 
uint16_t nwname,
        clnt = oldfid->clnt;
        if (clone) {
                fid = p9_fid_create(clnt);
-               if (IS_ERR(fid)) {
-                       err = PTR_ERR(fid);
-                       fid = NULL;
+               if (!fid) {
+                       err = -ENOMEM;
                        goto error;
                }
 
@@ -2018,9 +2014,8 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid 
*file_fid,
        err = 0;
        clnt = file_fid->clnt;
        attr_fid = p9_fid_create(clnt);
-       if (IS_ERR(attr_fid)) {
-               err = PTR_ERR(attr_fid);
-               attr_fid = NULL;
+       if (!attr_fid) {
+               err = -ENOMEM;
                goto error;
        }
        p9_debug(P9_DEBUG_9P,
-- 
2.18.0