__locked_re...a_with_flags(9)

💅 __locked_read_sk_user_data_with_flags(9) — the Kernel API Manual, bestie edition 🎀

okay so this is __locked_re...a_with_flags(9) from the Kernel API Manual, and the way I need you to understand it is: this is the picky little reader function. It only hands you the pointer if the flags you asked about are all set in sk_user_data. Otherwise? It gives you NULL and walks away. no notes. 🙈

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✨ NAME ✨

__locked_read_sk_user_data_with_flags — return the pointer only if the argument flags are all set in sk_user_data. Otherwise return NULL. that's it, that's the whole vibe check 🫶

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🌸 SYNOPSIS 🌸

void * __locked_read_sk_user_data_with_flags (const struct sock *sk ,
       uintptr_t flags );

like literally just two args, she's low maintenance 💅

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🦋 ARGUMENTS 🦋

• sk — the socket. the main character, the whole point, the socket in question 💖
• flags — flag bits. these are the bits she's gonna check against sk_user_data, and all of them have to be set or you get nothing back ✨

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👑 DESCRIPTION 👑

okay so the one rule, and it's not optional: the caller must be holding sk->sk_callback_lock. that's it. that's the whole description. no cap, it's short because it means it 😭

fr fr though, this is not a suggestion — it's a requirement. hold sk->sk_callback_lock before you call this. don't be the person who skips it. 💀

and remember how the NAME said it: you get the pointer back only if all of the argument flags are set in sk_user_data. otherwise it's NULL o'clock 🕐

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🧚 SEE ALSO 🧚

sibling functions and friends of the family, all iconic in their own right 🌈

• Kernel file ./include/net/sock.h
• struct sock_common(9)
• struct sock(9)
• sk_user_data_is_nocopy(9)
• __rcu_dereference_sk_user_data_with_flags(9)
• sk_for_each_entry_offset_rcu(9)
• SOCK_CONNECT_BIND(9)
• lock_sock_fast(9)
• unlock_sock_fast(9)
• sk_wmem_alloc_get(9)
• sk_rmem_alloc_get(9)
• sk_has_allocations(9)
• skwq_has_sleeper(9)
• sock_poll_wait(9)
• sk_page_frag(9)
• _sock_tx_timestamp(9)
• sk_eat_skb(9)

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and that's the page!! 💖 brought to you from ./include/net, dated October 2026, filed under __locked_re...a_with_flags(9) in the Kernel API Manual. mwah, go hold that lock 🫶✨🎀