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@xxxxxxxxxx>
Reviewed-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
---
v6:
- Move skb ref helpers to new header file (Jakub).
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)
fix mirror
---
.../chelsio/inline_crypto/ch_ktls/chcr_ktls.c | 2 +-
drivers/net/ethernet/sun/cassini.c | 4 +-
drivers/net/veth.c | 2 +-
include/linux/skbuff_ref.h | 39 ++++++++++++++--
net/core/skbuff.c | 46 ++-----------------
net/tls/tls_device_fallback.c | 2 +-
6 files changed, 44 insertions(+), 51 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 e8e460a92e0e..3832c2e8ea5a 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
@@ -1659,7 +1659,7 @@ 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 8f1f43dbb76d..f058e154a3bc 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -2000,7 +2000,7 @@ 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)) {
@@ -2024,7 +2024,7 @@ 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 426e68a95067..0b0293629329 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -717,7 +717,7 @@ 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_ref.h b/include/linux/skbuff_ref.h
index 11f0a4063403..4dcdbe9fbc5f 100644
--- a/include/linux/skbuff_ref.h
+++ b/include/linux/skbuff_ref.h
@@ -8,16 +8,47 @@
#define _LINUX_SKBUFF_REF_H
#include <linux/skbuff.h>
+#include <net/page_pool/helpers.h>
+
+#ifdef CONFIG_PAGE_POOL
+static inline bool is_pp_page(struct page *page)
+{
+ return (page->pp_magic & ~0x3UL) == PP_SIGNATURE;
+}
+
+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);
}
/**
@@ -29,7 +60,7 @@ 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);
}
bool napi_pp_put_page(struct page *page);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 38c09a70adc1..3c276f56537b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -907,11 +907,6 @@ 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)
{
@@ -1033,37 +1028,6 @@ 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)
@@ -4176,7 +4140,7 @@ 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);
@@ -4826,7 +4790,7 @@ 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) {
@@ -5957,10 +5921,8 @@ 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 f9e3d3d90dcf..9237dded4467 100644
--- a/net/tls/tls_device_fallback.c
+++ b/net/tls/tls_device_fallback.c
@@ -278,7 +278,7 @@ 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
