From: David Wei <[email protected]>
To: Jens Axboe <[email protected]>, Pavel Begunkov <[email protected]>
Cc: [email protected], Mina Almasry <[email protected]>,
Jakub Kicinski <[email protected]>
Subject: [PATCH 07/11] skbuff: add SKBFL_FIXED_FRAG and skb_fixed()
Date: Fri, 25 Aug 2023 15:55:46 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
From: David Wei <[email protected]>
When an skb that is marked as zero copy goes up the network stack during
RX, skb_orphan_frags_rx is called which then calls skb_copy_ubufs and
defeat the purpose of ZC.
This is because currently zero copy is only for TX and this behaviour is
designed to prevent TX zero copy data being redirected up the network
stack rather than new zero copy RX data coming from the driver.
This patch adds a new flag SKBFL_FIXED_FRAG and checks for this in
skb_orphan_frags, not calling skb_copy_ubufs if it is set.
Signed-off-by: David Wei <[email protected]>
Co-developed-by: Jonathan Lemon <[email protected]>
---
include/linux/skbuff.h | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8cff3d817131..d7ef998df4a5 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -518,6 +518,9 @@ enum {
* use frags only up until ubuf_info is released
*/
SKBFL_MANAGED_FRAG_REFS = BIT(4),
+
+ /* don't move or copy the fragment */
+ SKBFL_FIXED_FRAG = BIT(5),
};
#define SKBFL_ZEROCOPY_FRAG (SKBFL_ZEROCOPY_ENABLE | SKBFL_SHARED_FRAG)
@@ -1674,6 +1677,11 @@ static inline bool skb_zcopy_managed(const struct sk_buff *skb)
return skb_shinfo(skb)->flags & SKBFL_MANAGED_FRAG_REFS;
}
+static inline bool skb_fixed(const struct sk_buff *skb)
+{
+ return skb_shinfo(skb)->flags & SKBFL_FIXED_FRAG;
+}
+
static inline bool skb_pure_zcopy_same(const struct sk_buff *skb1,
const struct sk_buff *skb2)
{
@@ -3135,7 +3143,7 @@ static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
/* Frags must be orphaned, even if refcounted, if skb might loop to rx path */
static inline int skb_orphan_frags_rx(struct sk_buff *skb, gfp_t gfp_mask)
{
- if (likely(!skb_zcopy(skb)))
+ if (likely(!skb_zcopy(skb) || skb_fixed(skb)))
return 0;
return skb_copy_ubufs(skb, gfp_mask);
}
--
2.39.3
next prev parent reply other threads:[~2023-08-25 22:57 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-25 22:55 [RFC PATCH 00/11] Zero copy network RX using io_uring David Wei
2023-08-25 22:55 ` [PATCH 01/11] io_uring: add interface queue David Wei
2023-08-25 22:55 ` [PATCH 02/11] io_uring: add mmap support for shared ifq ringbuffers David Wei
2023-08-25 22:55 ` [PATCH 03/11] netdev: add XDP_SETUP_ZC_RX command David Wei
2023-08-25 22:55 ` [PATCH 04/11] io_uring: setup ZC for an RX queue when registering an ifq David Wei
2023-08-25 22:55 ` [PATCH 05/11] io_uring: add ZC buf and pool David Wei
2023-08-25 22:55 ` [PATCH 06/11] io_uring: add ZC pool API David Wei
2023-08-25 22:55 ` David Wei [this message]
2023-08-25 22:55 ` [PATCH 08/11] io_uring: allocate a uarg for freeing zero copy skbs David Wei
2023-08-25 22:55 ` [PATCH 09/11] io_uring: delay ZC pool destruction David Wei
2023-08-25 22:55 ` [PATCH 10/11] netdev/bnxt: add data pool and use it in BNXT driver David Wei
2023-08-25 22:55 ` [PATCH 11/11] io_uring: add io_recvzc request David Wei
2023-08-26 0:04 ` [RFC PATCH 00/11] Zero copy network RX using io_uring Jakub Kicinski
-- strict thread matches above, loose matches on Subject: below --
2023-08-26 1:19 [RFC RESEND " David Wei
2023-08-26 1:19 ` [PATCH 07/11] skbuff: add SKBFL_FIXED_FRAG and skb_fixed() David Wei
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