Re: [PATCH net-next v9 2/8] netmem: introduce utility APIs to use struct netmem_desc
From: Pavel Begunkov <asml.silence@gmail.com>
Date: 2025-07-12 11:58:19
Also in:
bpf, linux-mm, linux-rdma, lkml
On 7/10/25 09:28, Byungchul Park wrote: ...> +
quoted hunk ↗ jump to hunk
static inline struct net_iov *netmem_to_net_iov(netmem_ref netmem) { if (netmem_is_net_iov(netmem))@@ -314,6 +340,21 @@ static inline netmem_ref netmem_compound_head(netmem_ref netmem) return page_to_netmem(compound_head(netmem_to_page(netmem))); } +#define nmdesc_to_page(nmdesc) (_Generic((nmdesc), \ + const struct netmem_desc * : (const struct page *)(nmdesc), \ + struct netmem_desc * : (struct page *)(nmdesc)))
Considering that nmdesc is going to be separated from pages and accessed through indirection, and back reference to the page is not needed (at least for net/), this helper shouldn't even exist. And in fact, you don't really use it ...
+static inline struct netmem_desc *page_to_nmdesc(struct page *page)
+{
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ return (struct netmem_desc *)page;
+}
+
+static inline void *nmdesc_address(struct netmem_desc *nmdesc)
+{
+ return page_address(nmdesc_to_page(nmdesc));
+}... That's the only caller, and nmdesc_address() is not used, so just nuke both of them. This helper doesn't even make sense. Please avoid introducing functions that you don't use as a general rule.
+ /** * __netmem_address - unsafely get pointer to the memory backing @netmem * @netmem: netmem reference to get the pointer for
-- Pavel Begunkov