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authorSabrina Dubroca <sd@queasysnail.net>2021-04-16 18:11:46 +0300
committerSteffen Klassert <steffen.klassert@secunet.com>2021-04-19 13:49:29 +0300
commit747b67088f8d34b3ec64d31447a1044be92dd348 (patch)
tree67a3a9e9fd18a48a8270fc903a4f62a50b1f3be4 /net/xfrm
parent6218fe186109b93a2fa2343e13981e016e9961ab (diff)
downloadlinux-747b67088f8d34b3ec64d31447a1044be92dd348.tar.xz
xfrm: ipcomp: remove unnecessary get_cpu()
While testing ipcomp on a realtime kernel, Xiumei reported a "sleeping in atomic" bug, caused by a memory allocation while preemption is disabled (ipcomp_decompress -> alloc_page -> ... get_page_from_freelist). As Sebastian noted [1], this get_cpu() isn't actually needed, since ipcomp_decompress() is called in napi context anyway, so BH is already disabled. This patch replaces get_cpu + per_cpu_ptr with this_cpu_ptr, then simplifies the error returns, since there isn't any common operation left. [1] https://lore.kernel.org/lkml/20190820082810.ixkmi56fp7u7eyn2@linutronix.de/ Cc: Juri Lelli <jlelli@redhat.com> Reported-by: Xiumei Mu <xmu@redhat.com> Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/xfrm')
-rw-r--r--net/xfrm/xfrm_ipcomp.c25
1 files changed, 8 insertions, 17 deletions
diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index 4d422447aadc..2e8afe078d61 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -41,19 +41,16 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
const int plen = skb->len;
int dlen = IPCOMP_SCRATCH_SIZE;
const u8 *start = skb->data;
- const int cpu = get_cpu();
- u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
- struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
+ u8 *scratch = *this_cpu_ptr(ipcomp_scratches);
+ struct crypto_comp *tfm = *this_cpu_ptr(ipcd->tfms);
int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
int len;
if (err)
- goto out;
+ return err;
- if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
- err = -EINVAL;
- goto out;
- }
+ if (dlen < (plen + sizeof(struct ip_comp_hdr)))
+ return -EINVAL;
len = dlen - plen;
if (len > skb_tailroom(skb))
@@ -68,16 +65,14 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
skb_frag_t *frag;
struct page *page;
- err = -EMSGSIZE;
if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
- goto out;
+ return -EMSGSIZE;
frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
page = alloc_page(GFP_ATOMIC);
- err = -ENOMEM;
if (!page)
- goto out;
+ return -ENOMEM;
__skb_frag_set_page(frag, page);
@@ -96,11 +91,7 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
skb_shinfo(skb)->nr_frags++;
}
- err = 0;
-
-out:
- put_cpu();
- return err;
+ return 0;
}
int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)