[PATCH 1/6] 9p: Change p9_fid_create calling convention

From: Matthew Wilcox
Date: Thu Jun 28 2018 - 09:28:10 EST


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 <willy@xxxxxxxxxxxxx>
---
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 18c5271910dc..f8d58b0852fe 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