On 2018/7/12 5:02, Matthew Wilcox wrote:
> 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>
Reviewed-by: Yiwen Jiang <jiangyiwen@xxxxxxxxx>
> ---
> 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,
>
