Messages in this thread Patch in this message | | | Date | Mon, 8 Apr 2024 08:29:57 -0700 | Subject | [PATCH net-next v5 2/3] net: mirror skb frag ref/unref helpers | From | Mina Almasry <> |
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Refactor some of the skb frag ref/unref helpers for improved clarity.
Implement napi_pp_get_page() to be the mirror counterpart of napi_pp_put_page().
Implement skb_page_ref() to be the mirror of skb_page_unref().
Improve __skb_frag_ref() to become a mirror counterpart of __skb_frag_unref(). Previously unref could handle pp & non-pp pages, while the ref could only handle non-pp pages. Now both the ref & unref helpers can correctly handle both pp & non-pp pages.
Now that __skb_frag_ref() can handle both pp & non-pp pages, remove skb_pp_frag_ref(), and use __skb_frag_ref() instead. This lets us remove pp specific handling from skb_try_coalesce.
Additionally, since __skb_frag_ref() can now handle both pp & non-pp pages, a latent issue in skb_shift() should now be fixed. Previously this function would do a non-pp ref & pp unref on potential pp frags (fragfrom). After this patch, skb_shift() should correctly do a pp ref/unref on pp frags.
Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
---
v5: - Made changes to inline napi_pp_get_page() (Eric). I had to move page_pool_ref_page() from include/net/page_pool/helpers.h to include/linux/skbuff.h, so I don't add more includes to skbuff.h, which slows down the incremental builds.
v4: - pass skb->pp_recycle instead of 'false' in __skb_frag_ref in chcr_ktls.c & cassini.c. - Add some details on the changes to skb_shift() in this commit in the commit message.
v3: - Fix build errors reported by patchwork. - Fix drivers/net/veth.c & tls_device_fallback.c callsite I missed to update. - Fix page_pool_ref_page(head_page) -> page_pool_ref_page(page)
--- .../chelsio/inline_crypto/ch_ktls/chcr_ktls.c | 2 +- drivers/net/ethernet/sun/cassini.c | 4 +- drivers/net/veth.c | 2 +- include/linux/skbuff.h | 44 ++++++++++++++++-- include/net/page_pool/helpers.h | 5 -- net/core/skbuff.c | 46 ++----------------- net/tls/tls_device_fallback.c | 2 +- 7 files changed, 49 insertions(+), 56 deletions(-)
diff --git a/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c b/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c index 6482728794dd..d7e8deafddf1 100644 --- a/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c +++ b/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c @@ -1658,7 +1658,7 @@ static void chcr_ktls_copy_record_in_skb(struct sk_buff *nskb, for (i = 0; i < record->num_frags; i++) { skb_shinfo(nskb)->frags[i] = record->frags[i]; /* increase the frag ref count */ - __skb_frag_ref(&skb_shinfo(nskb)->frags[i]); + __skb_frag_ref(&skb_shinfo(nskb)->frags[i], nskb->pp_recycle); } skb_shinfo(nskb)->nr_frags = record->num_frags; diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c index bfb903506367..31878256feee 100644 --- a/drivers/net/ethernet/sun/cassini.c +++ b/drivers/net/ethernet/sun/cassini.c @@ -1999,7 +1999,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, skb->len += hlen - swivel; skb_frag_fill_page_desc(frag, page->buffer, off, hlen - swivel); - __skb_frag_ref(frag); + __skb_frag_ref(frag, skb->pp_recycle); /* any more data? */ if ((words[0] & RX_COMP1_SPLIT_PKT) && ((dlen -= hlen) > 0)) { @@ -2023,7 +2023,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, frag++; skb_frag_fill_page_desc(frag, page->buffer, 0, hlen); - __skb_frag_ref(frag); + __skb_frag_ref(frag, skb->pp_recycle); RX_USED_ADD(page, hlen + cp->crc_size); } diff --git a/drivers/net/veth.c b/drivers/net/veth.c index bcdfbf61eb66..6160a3e8d341 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -716,7 +716,7 @@ static void veth_xdp_get(struct xdp_buff *xdp) return; for (i = 0; i < sinfo->nr_frags; i++) - __skb_frag_ref(&sinfo->frags[i]); + __skb_frag_ref(&sinfo->frags[i], false); } static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq, diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index c0ff85bb087a..2e6a77c398e6 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3492,15 +3492,51 @@ static inline struct page *skb_frag_page(const skb_frag_t *frag) return netmem_to_page(frag->netmem); } +#ifdef CONFIG_PAGE_POOL +static inline bool is_pp_page(struct page *page) +{ + return (page->pp_magic & ~0x3UL) == PP_SIGNATURE; +} + +/* page_pool_unref_page() lives in net/page_pool/helpers.h */ +static inline void page_pool_ref_page(struct page *page) +{ + atomic_long_inc(&page->pp_ref_count); +} + +static inline bool napi_pp_get_page(struct page *page) +{ + page = compound_head(page); + + if (!is_pp_page(page)) + return false; + + page_pool_ref_page(page); + return true; +} +#endif + +static inline void skb_page_ref(struct page *page, bool recycle) +{ +#ifdef CONFIG_PAGE_POOL + if (recycle && napi_pp_get_page(page)) + return; +#endif + get_page(page); +} + /** * __skb_frag_ref - take an addition reference on a paged fragment. * @frag: the paged fragment + * @recycle: skb->pp_recycle param of the parent skb. False if no parent skb. * - * Takes an additional reference on the paged fragment @frag. + * Takes an additional reference on the paged fragment @frag. Obtains the + * correct reference count depending on whether skb->pp_recycle is set and + * whether the frag is a page pool frag. */ -static inline void __skb_frag_ref(skb_frag_t *frag) +static inline void __skb_frag_ref(skb_frag_t *frag, bool recycle) { - get_page(skb_frag_page(frag)); + skb_page_ref(skb_frag_page(frag), recycle); } /** @@ -3512,7 +3548,7 @@ static inline void __skb_frag_ref(skb_frag_t *frag) */ static inline void skb_frag_ref(struct sk_buff *skb, int f) { - __skb_frag_ref(&skb_shinfo(skb)->frags[f]); + __skb_frag_ref(&skb_shinfo(skb)->frags[f], skb->pp_recycle); } int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb, diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 1d397c1a0043..ead2c0d24b2c 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -277,11 +277,6 @@ static inline long page_pool_unref_page(struct page *page, long nr) return ret; } -static inline void page_pool_ref_page(struct page *page) -{ - atomic_long_inc(&page->pp_ref_count); -} - static inline bool page_pool_is_last_ref(struct page *page) { /* If page_pool_unref_page() returns 0, we were the last user */ diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 21cd01641f4c..928c615b0fd8 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -906,11 +906,6 @@ static void skb_clone_fraglist(struct sk_buff *skb) skb_get(list); } -static bool is_pp_page(struct page *page) -{ - return (page->pp_magic & ~0x3UL) == PP_SIGNATURE; -} - int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb, unsigned int headroom) { @@ -1032,37 +1027,6 @@ static bool skb_pp_recycle(struct sk_buff *skb, void *data) return napi_pp_put_page(virt_to_page(data)); } -/** - * skb_pp_frag_ref() - Increase fragment references of a page pool aware skb - * @skb: page pool aware skb - * - * Increase the fragment reference count (pp_ref_count) of a skb. This is - * intended to gain fragment references only for page pool aware skbs, - * i.e. when skb->pp_recycle is true, and not for fragments in a - * non-pp-recycling skb. It has a fallback to increase references on normal - * pages, as page pool aware skbs may also have normal page fragments. - */ -static int skb_pp_frag_ref(struct sk_buff *skb) -{ - struct skb_shared_info *shinfo; - struct page *head_page; - int i; - - if (!skb->pp_recycle) - return -EINVAL; - - shinfo = skb_shinfo(skb); - - for (i = 0; i < shinfo->nr_frags; i++) { - head_page = compound_head(skb_frag_page(&shinfo->frags[i])); - if (likely(is_pp_page(head_page))) - page_pool_ref_page(head_page); - else - page_ref_inc(head_page); - } - return 0; -} - static void skb_kfree_head(void *head, unsigned int end_offset) { if (end_offset == SKB_SMALL_HEAD_HEADROOM) @@ -4175,7 +4139,7 @@ int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen) to++; } else { - __skb_frag_ref(fragfrom); + __skb_frag_ref(fragfrom, skb->pp_recycle); skb_frag_page_copy(fragto, fragfrom); skb_frag_off_copy(fragto, fragfrom); skb_frag_size_set(fragto, todo); @@ -4825,7 +4789,7 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, } *nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag; - __skb_frag_ref(nskb_frag); + __skb_frag_ref(nskb_frag, nskb->pp_recycle); size = skb_frag_size(nskb_frag); if (pos < offset) { @@ -5956,10 +5920,8 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, /* if the skb is not cloned this does nothing * since we set nr_frags to 0. */ - if (skb_pp_frag_ref(from)) { - for (i = 0; i < from_shinfo->nr_frags; i++) - __skb_frag_ref(&from_shinfo->frags[i]); - } + for (i = 0; i < from_shinfo->nr_frags; i++) + __skb_frag_ref(&from_shinfo->frags[i], from->pp_recycle); to->truesize += delta; to->len += len; diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c index 4e7228f275fa..d4000b4a1f7d 100644 --- a/net/tls/tls_device_fallback.c +++ b/net/tls/tls_device_fallback.c @@ -277,7 +277,7 @@ static int fill_sg_in(struct scatterlist *sg_in, for (i = 0; remaining > 0; i++) { skb_frag_t *frag = &record->frags[i]; - __skb_frag_ref(frag); + __skb_frag_ref(frag, false); sg_set_page(sg_in + i, skb_frag_page(frag), skb_frag_size(frag), skb_frag_off(frag)); -- 2.44.0.478.gd926399ef9-goog
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