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Subject[PATCH v4 net-next 01/11] skbuff: move __alloc_skb() next to the other skb allocation functions
In preparation before reusing several functions in all three skb
allocation variants, move __alloc_skb() next to the
__netdev_alloc_skb() and __napi_alloc_skb().
No functional changes.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
net/core/skbuff.c | 284 +++++++++++++++++++++++-----------------------
1 file changed, 142 insertions(+), 142 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d380c7b5a12d..a0f846872d19 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -119,148 +119,6 @@ static void skb_under_panic(struct sk_buff *skb, unsigned int sz, void *addr)
skb_panic(skb, sz, addr, __func__);
}

-/*
- * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
- * the caller if emergency pfmemalloc reserves are being used. If it is and
- * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
- * may be used. Otherwise, the packet data may be discarded until enough
- * memory is free
- */
-#define kmalloc_reserve(size, gfp, node, pfmemalloc) \
- __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
-
-static void *__kmalloc_reserve(size_t size, gfp_t flags, int node,
- unsigned long ip, bool *pfmemalloc)
-{
- void *obj;
- bool ret_pfmemalloc = false;
-
- /*
- * Try a regular allocation, when that fails and we're not entitled
- * to the reserves, fail.
- */
- obj = kmalloc_node_track_caller(size,
- flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
- node);
- if (obj || !(gfp_pfmemalloc_allowed(flags)))
- goto out;
-
- /* Try again but now we are using pfmemalloc reserves */
- ret_pfmemalloc = true;
- obj = kmalloc_node_track_caller(size, flags, node);
-
-out:
- if (pfmemalloc)
- *pfmemalloc = ret_pfmemalloc;
-
- return obj;
-}
-
-/* Allocate a new skbuff. We do this ourselves so we can fill in a few
- * 'private' fields and also do memory statistics to find all the
- * [BEEP] leaks.
- *
- */
-
-/**
- * __alloc_skb - allocate a network buffer
- * @size: size to allocate
- * @gfp_mask: allocation mask
- * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
- * instead of head cache and allocate a cloned (child) skb.
- * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
- * allocations in case the data is required for writeback
- * @node: numa node to allocate memory on
- *
- * Allocate a new &sk_buff. The returned buffer has no headroom and a
- * tail room of at least size bytes. The object has a reference count
- * of one. The return is the buffer. On a failure the return is %NULL.
- *
- * Buffers may only be allocated from interrupts using a @gfp_mask of
- * %GFP_ATOMIC.
- */
-struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
- int flags, int node)
-{
- struct kmem_cache *cache;
- struct skb_shared_info *shinfo;
- struct sk_buff *skb;
- u8 *data;
- bool pfmemalloc;
-
- cache = (flags & SKB_ALLOC_FCLONE)
- ? skbuff_fclone_cache : skbuff_head_cache;
-
- if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
- gfp_mask |= __GFP_MEMALLOC;
-
- /* Get the HEAD */
- skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
- if (!skb)
- goto out;
- prefetchw(skb);
-
- /* We do our best to align skb_shared_info on a separate cache
- * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
- * aligned memory blocks, unless SLUB/SLAB debug is enabled.
- * Both skb->head and skb_shared_info are cache line aligned.
- */
- size = SKB_DATA_ALIGN(size);
- size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
- if (!data)
- goto nodata;
- /* kmalloc(size) might give us more room than requested.
- * Put skb_shared_info exactly at the end of allocated zone,
- * to allow max possible filling before reallocation.
- */
- size = SKB_WITH_OVERHEAD(ksize(data));
- prefetchw(data + size);
-
- /*
- * Only clear those fields we need to clear, not those that we will
- * actually initialise below. Hence, don't put any more fields after
- * the tail pointer in struct sk_buff!
- */
- memset(skb, 0, offsetof(struct sk_buff, tail));
- /* Account for allocated memory : skb + skb->head */
- skb->truesize = SKB_TRUESIZE(size);
- skb->pfmemalloc = pfmemalloc;
- refcount_set(&skb->users, 1);
- skb->head = data;
- skb->data = data;
- skb_reset_tail_pointer(skb);
- skb->end = skb->tail + size;
- skb->mac_header = (typeof(skb->mac_header))~0U;
- skb->transport_header = (typeof(skb->transport_header))~0U;
-
- /* make sure we initialize shinfo sequentially */
- shinfo = skb_shinfo(skb);
- memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
- atomic_set(&shinfo->dataref, 1);
-
- if (flags & SKB_ALLOC_FCLONE) {
- struct sk_buff_fclones *fclones;
-
- fclones = container_of(skb, struct sk_buff_fclones, skb1);
-
- skb->fclone = SKB_FCLONE_ORIG;
- refcount_set(&fclones->fclone_ref, 1);
-
- fclones->skb2.fclone = SKB_FCLONE_CLONE;
- }
-
- skb_set_kcov_handle(skb, kcov_common_handle());
-
-out:
- return skb;
-nodata:
- kmem_cache_free(cache, skb);
- skb = NULL;
- goto out;
-}
-EXPORT_SYMBOL(__alloc_skb);
-
/* Caller must provide SKB that is memset cleared */
static struct sk_buff *__build_skb_around(struct sk_buff *skb,
void *data, unsigned int frag_size)
@@ -408,6 +266,148 @@ void *__netdev_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
}
EXPORT_SYMBOL(__netdev_alloc_frag_align);

+/*
+ * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
+ * the caller if emergency pfmemalloc reserves are being used. If it is and
+ * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
+ * may be used. Otherwise, the packet data may be discarded until enough
+ * memory is free
+ */
+#define kmalloc_reserve(size, gfp, node, pfmemalloc) \
+ __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
+
+static void *__kmalloc_reserve(size_t size, gfp_t flags, int node,
+ unsigned long ip, bool *pfmemalloc)
+{
+ void *obj;
+ bool ret_pfmemalloc = false;
+
+ /*
+ * Try a regular allocation, when that fails and we're not entitled
+ * to the reserves, fail.
+ */
+ obj = kmalloc_node_track_caller(size,
+ flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
+ node);
+ if (obj || !(gfp_pfmemalloc_allowed(flags)))
+ goto out;
+
+ /* Try again but now we are using pfmemalloc reserves */
+ ret_pfmemalloc = true;
+ obj = kmalloc_node_track_caller(size, flags, node);
+
+out:
+ if (pfmemalloc)
+ *pfmemalloc = ret_pfmemalloc;
+
+ return obj;
+}
+
+/* Allocate a new skbuff. We do this ourselves so we can fill in a few
+ * 'private' fields and also do memory statistics to find all the
+ * [BEEP] leaks.
+ *
+ */
+
+/**
+ * __alloc_skb - allocate a network buffer
+ * @size: size to allocate
+ * @gfp_mask: allocation mask
+ * @flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
+ * instead of head cache and allocate a cloned (child) skb.
+ * If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
+ * allocations in case the data is required for writeback
+ * @node: numa node to allocate memory on
+ *
+ * Allocate a new &sk_buff. The returned buffer has no headroom and a
+ * tail room of at least size bytes. The object has a reference count
+ * of one. The return is the buffer. On a failure the return is %NULL.
+ *
+ * Buffers may only be allocated from interrupts using a @gfp_mask of
+ * %GFP_ATOMIC.
+ */
+struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
+ int flags, int node)
+{
+ struct kmem_cache *cache;
+ struct skb_shared_info *shinfo;
+ struct sk_buff *skb;
+ u8 *data;
+ bool pfmemalloc;
+
+ cache = (flags & SKB_ALLOC_FCLONE)
+ ? skbuff_fclone_cache : skbuff_head_cache;
+
+ if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
+ gfp_mask |= __GFP_MEMALLOC;
+
+ /* Get the HEAD */
+ skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
+ if (!skb)
+ goto out;
+ prefetchw(skb);
+
+ /* We do our best to align skb_shared_info on a separate cache
+ * line. It usually works because kmalloc(X > SMP_CACHE_BYTES) gives
+ * aligned memory blocks, unless SLUB/SLAB debug is enabled.
+ * Both skb->head and skb_shared_info are cache line aligned.
+ */
+ size = SKB_DATA_ALIGN(size);
+ size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
+ if (!data)
+ goto nodata;
+ /* kmalloc(size) might give us more room than requested.
+ * Put skb_shared_info exactly at the end of allocated zone,
+ * to allow max possible filling before reallocation.
+ */
+ size = SKB_WITH_OVERHEAD(ksize(data));
+ prefetchw(data + size);
+
+ /*
+ * Only clear those fields we need to clear, not those that we will
+ * actually initialise below. Hence, don't put any more fields after
+ * the tail pointer in struct sk_buff!
+ */
+ memset(skb, 0, offsetof(struct sk_buff, tail));
+ /* Account for allocated memory : skb + skb->head */
+ skb->truesize = SKB_TRUESIZE(size);
+ skb->pfmemalloc = pfmemalloc;
+ refcount_set(&skb->users, 1);
+ skb->head = data;
+ skb->data = data;
+ skb_reset_tail_pointer(skb);
+ skb->end = skb->tail + size;
+ skb->mac_header = (typeof(skb->mac_header))~0U;
+ skb->transport_header = (typeof(skb->transport_header))~0U;
+
+ /* make sure we initialize shinfo sequentially */
+ shinfo = skb_shinfo(skb);
+ memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
+ atomic_set(&shinfo->dataref, 1);
+
+ if (flags & SKB_ALLOC_FCLONE) {
+ struct sk_buff_fclones *fclones;
+
+ fclones = container_of(skb, struct sk_buff_fclones, skb1);
+
+ skb->fclone = SKB_FCLONE_ORIG;
+ refcount_set(&fclones->fclone_ref, 1);
+
+ fclones->skb2.fclone = SKB_FCLONE_CLONE;
+ }
+
+ skb_set_kcov_handle(skb, kcov_common_handle());
+
+out:
+ return skb;
+nodata:
+ kmem_cache_free(cache, skb);
+ skb = NULL;
+ goto out;
+}
+EXPORT_SYMBOL(__alloc_skb);
+
/**
* __netdev_alloc_skb - allocate an skbuff for rx on a specific device
* @dev: network device to receive on
--
2.30.1

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