Re: [PATCH] net: sched: One function call less in em_meta_change() after error detection
From: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Date: 2015-01-31 17:31:15
Also in:
kernel-janitors, lkml
Hi, On 31.01.2015 17:34, SF Markus Elfring wrote:
quoted hunk ↗ jump to hunk
From: Markus Elfring <redacted> Date: Sat, 31 Jan 2015 17:18:48 +0100 The meta_delete() function could be called in four cases by the em_meta_change() function during error handling even if the passed variable "meta" contained still a null pointer. * This implementation detail could be improved by adjustments for jump labels. * Let us return immediately after the first failed function call according to the current Linux coding style convention. * Let us delete also unnecessary checks for the variables "err" and "meta" there. Signed-off-by: Markus Elfring <redacted> --- net/sched/em_meta.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)diff --git a/net/sched/em_meta.c b/net/sched/em_meta.c index b5294ce..2aa67b1 100644 --- a/net/sched/em_meta.c +++ b/net/sched/em_meta.c@@ -866,23 +866,23 @@ static int em_meta_change(struct net *net, void *data, int len, err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy); if (err < 0) - goto errout; + return err; err = -EINVAL; if (tb[TCA_EM_META_HDR] == NULL) - goto errout; + goto exit; hdr = nla_data(tb[TCA_EM_META_HDR]); if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) || TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX || TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX || TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX) - goto errout; + goto exit; meta = kzalloc(sizeof(*meta), GFP_KERNEL); if (meta == NULL) { err = -ENOMEM; - goto errout; + goto exit; } memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));@@ -891,20 +891,20 @@ static int em_meta_change(struct net *net, void *data, int len, if (!meta_is_supported(&meta->lvalue) || !meta_is_supported(&meta->rvalue)) { err = -EOPNOTSUPP; - goto errout; + goto delete_meta; } if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 || meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0) - goto errout; + goto delete_meta; m->datalen = sizeof(*meta); m->data = (unsigned long) meta; - err = 0; -errout: - if (err && meta) - meta_delete(meta); + return 0; +delete_meta: + meta_delete(meta); +exit: return err; }
Why do you use that exit label if it does nothing more than returning the error value? Also if nla_parse fails you dont use it but return the error directly. While using a label which is used only to return an error may be a matter of taste, its at least inconsistent to do both in a function, use such a label in one case and return immediately in another, isnt it? Regards, Lino