___change_bit(9)

💖 NAME

okay so bestie, welcome to the Kernel API Manual — the main character today is ___change_bit(9), and its whole vibe is flipping a single bit in memory. That's it. That's the gig. 💅

✨ SYNOPSIS

void ___change_bit (unsigned long nr , volatile unsigned long *addr );

🎀 ARGUMENTS

• nr — the bit to change. this is the bit you're toggling, bestie.
• addr — the address to start counting from. yes, literally the starting address for the counting situation.

🦋 DESCRIPTION

okay so real talk: unlike change_bit, this function is non-atomic and may be reordered. it is absolutely not giving "safe simultaneous vibes."

🚨 if it's called on the same region of memory simultaneously, the effect may be that only one operation succeeds. so like… don't expect both calls to land, because that's literally the warning.

🌈 SEE ALSO

• Kernel file: ./tools/include/asm-generic/bitops/non-atomic.h
• ___set_bit(9)
• ___test_and_set_bit(9)
• ___test_and_clear_bit(9)
• _test_bit(9)

mwah 💋 this lil page came from ./tools/include/asm-generic/bi... and it's dated October 2026 — periodt. 🫶