From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 69B4F47988C for ; Fri, 31 Jul 2026 16:20:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785514856; cv=none; b=tK8OhabpXb6HoxUMMfDqLEvrAGEAiO99hhrVMYUWH2OygX383l6e0wFvC92u2Dc1V6ABkJTAnLEKWr/YJiqUcFFWKFuFLRtbo+POCiJn3h15GuuocLMADYNFjJtTg/MMsyfHmEcLANAsK4MKkW7e3kNKP5F/O5aiAReHeso/hzQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785514856; c=relaxed/simple; bh=mN2iX8Z5zX5qtBCnaXzCxjsKWUiQDrZ48Y99zlVkxio=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=QYpSloCor7zsAUgfT+lOBbkpG3swePLx+xPShmiz+RiKw31danMGh43xgUnKYFVEBew7+tCnhHV+PQI07h+yo5WkX2ol4aKhCZlbg3tEDrZk3eUmw+pDae6IpRMgFRpDLuyRTwStv4BWWD95bmZPRUBq1aKZ/iQXfP2m/3oDCTk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=pSj/VEdO; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=aSJb6N4G; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=Xi9hN4Kp; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=b6JpNAWz; arc=none smtp.client-ip=195.135.223.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="pSj/VEdO"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="aSJb6N4G"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="Xi9hN4Kp"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="b6JpNAWz" Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id AA2BC4149; Fri, 31 Jul 2026 16:20:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1785514846; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=MruqvTvGmsky1Hcwgom4mOLdCN1z/IAud4ovvSmFkMM=; b=pSj/VEdOSpchcfuwnWVuH8olMuCI0wdLTiSFGeJDeZyFcuYX8VYx9VXKYd34FG1UE9Ts7m AsFl4xp6YzGCZJLjmLNJmudd8dPxhSh7k/bKQdIRV3Cu67649Zfy4VnyIx8oF0BKr+xDfj WiDaPWKCtLfxha2mpOaVUcMd2L93lW0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1785514846; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=MruqvTvGmsky1Hcwgom4mOLdCN1z/IAud4ovvSmFkMM=; b=aSJb6N4GDrXm71IsrLkcvCfjFaWRc8ZJjCkHP/f2grI5L6L5W3gbfQWDgg3p2J1KA1ApOw PFj6XJjkrJsJEVCA== Authentication-Results: smtp-out2.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1785514842; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=MruqvTvGmsky1Hcwgom4mOLdCN1z/IAud4ovvSmFkMM=; b=Xi9hN4KpLFQC8mvU1I6WjSvtY/vj0WLviZE8HZiDwmnZsmQeFr+z7j5NvKx1idMBQ9m/fp Itv4BtEfyu6HXtKbpDNPMW8t+M4Z4Pe/BfqkTR8wpYN4K3iZfV1GWXNsYwrlUDF2hwk3u5 7mAqhTOnIXplh1puexP57PH/J+A/0jg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1785514842; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=MruqvTvGmsky1Hcwgom4mOLdCN1z/IAud4ovvSmFkMM=; b=b6JpNAWzBDOuLmccosr9WyJ1t17fnJwjbYhTg7HIUF0iW4ql1gQ0v7gNN8v8Nu9BcQa+t2 cprt47oD5f5RZOCQ== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 5A425779B0; Fri, 31 Jul 2026 16:20:42 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 0RUDClrLbGpiawAAD6G6ig (envelope-from ); Fri, 31 Jul 2026 16:20:42 +0000 From: Gabriel Krisman Bertazi To: axboe@kernel.dk Cc: io-uring@vger.kernel.org, Gabriel Krisman Bertazi Subject: [PATCH liburing] man: Fix FUTEX_WAIT/FUTEX_WAKE explanation Date: Fri, 31 Jul 2026 12:20:35 -0400 Message-ID: <20260731162035.3882874-1-krisman@suse.de> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; FROM_EQ_ENVFROM(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.de:mid,suse.de:email]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] X-Spam-Flag: NO X-Spam-Score: -2.80 X-Spam-Level: The description of the futex_wait parameters is incorrect when explaining the futex value. Correct it and rewrite the rest of the futex operations description to make them clearer. Closes: https://github.com/axboe/liburing/issues/1625 Signed-off-by: Gabriel Krisman Bertazi --- man/io_uring_enter.2 | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) diff --git a/man/io_uring_enter.2 b/man/io_uring_enter.2 index 7b99335e..b2e93f43 100644 --- a/man/io_uring_enter.2 +++ b/man/io_uring_enter.2 @@ -1538,20 +1538,19 @@ system call. .I addr must hold a pointer to the futex, .I addr2 -must hold the value to which the futex has to be changed so this caller to -.BR futex_wait (2) -can be woken by a call to -.BR futex_wake (2), +must hold the value of the futex word read by the application when +submitting the operation. The kernel will only put the task to sleep +and wait on the futex if, at the time of queueing, the futex word still +matches this value. .I addr3 -must hold the bitmask of this +must hold a bitmask of this .BR futex_wait (2) -caller. -For a caller of -.BR futex_wake (2) -to wake a waiter additionally the bitmask of the waiter and waker must have -at least one set bit in common. +caller, which will be used as a key by the kernel when +deciding which callers to wake up. .I fd -must contain additional flags passed in. +may contain additional flags following the +.B futex2 +interface flags. Available since 6.7. @@ -1561,17 +1560,19 @@ Issues the equivalent of the .BR futex_wake (2) system call. .I addr -must hold a pointer to the futex, +must hold a pointer to the futex to be awaken, .I addr2 -must hold the maximum number of waiters waiting on this futex to wake, +must hold the maximum number of waiters to be awaken by this call, .I addr3 -must hold the bitmask of this -.BR futex_wake (2) -call. -To wake a waiter additionally the bitmask of the waiter and waker must have -at least one set bit in common. +must hold a bitmask identifying which callers to wake. +A waker will be waken if at least one bit of the bitmask matches, +subject to the limit of waiters set by +.IR addr2 . .I fd -must contain additional flags passed in. +may contain additional flags following +the +.B futex2 +interface flags. Available since 6.7. -- 2.55.0