From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 D3BBA3B19DB for ; Tue, 21 Apr 2026 10:46:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776768420; cv=none; b=DvakjAXuTzQGLvKzhDtIBiuJ8m2ZHU6zIbGsWleM0ri3w5cK34VYUuy3VBj7gJiUj6Tcl1ROLuaOuOSf/015kBWxVGxQQSyliDuyj1i78JWWqANA0+/ZaK1IhFzkGcMFcwY3aGhz5CGwu2tDQ5uMsHCIR0ILzwfyPyK/ARJx2HM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776768420; c=relaxed/simple; bh=YE4xEaEm8Z1Zs64xYb7Sws3wIREFQx5oDmUEPY36rg4=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=H3bcgYxXTmmOU7Rojj9bnYLOsl9u7Csv8bugAchsZF6RT0XUCQMAEKIILWq9Vv/2VJWpGSJMOQCRdC5tYLCjkF9+0jfuNxGdB5808vrKv0tlBB3hp3sAgqokNabVtNFP8meWtXB6O4pQ0WPyv0wPXGobWBQ8Phf2LtysSU8r/aA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--joonwonkang.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=jBv0HISO; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--joonwonkang.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="jBv0HISO" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2b2ec17dc21so46400115ad.2 for ; Tue, 21 Apr 2026 03:46:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1776768418; x=1777373218; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=/udOUGzEjCi79/97ZZ0JQxYDEIsvCahdDGc/3JE8Y1U=; b=jBv0HISOQleBOC7oZWnca21gfJnBPMDtXTTs56oqZKBiRyX3bD4kVGawtDFhiyBtzg H3dC3GfZSQ4MvBApXUIvqeIJx3/rYun8p/xxsmoi19qyDGyOu8LGPiC8MXyQ1OLby1ex alxHVccPKHHgzqULf6q5+0qKFNkPocLKCStu8F6b6DCBrsR8tLZoHFQlEwvb/s/ucnJ6 aX/SI63SLk/rs8YmGbVuH732c6C/3ouKjc8mQmN9uiRmVY4ULIaDldqp4vuJuFp0hB63 VCZyp895oCEIs6zDRh2KKyVLC0JFrD4zHqwLa/wStdbx1m8omvNw11KlFvff0OJEpixd Hlng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776768418; x=1777373218; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=/udOUGzEjCi79/97ZZ0JQxYDEIsvCahdDGc/3JE8Y1U=; b=GM24K6jGQr9owHlJqaLMYiCQxt5n31iMZpeUOhGMW6+HP/gJxatYnC6I5fZdmlxrBJ knOakwOeV/y0tlvHKqHicZJx9qTCoDCiopVK1H1uqmMRbzDcFDWaSFb3LuB90USxQ34d a6E4siuVLbCv9fLHJEbhVCUvlBVrWKhGBlU9j+s8Cm1sM5rSJtcswueb1hBVascbntNV B9IXNlhpF9gFelkdbfbdm5d8i/VBKY7K4pgshRDA4+DhZyoYu5VqCioX51SDGPqR9Q6S JNiI3sCZazm2xus2/+fdzoNi9ooXLZaJOrM5m0RcxjJwTFaLcsdL4FxucrrxX3BLxgs1 1rBA== X-Gm-Message-State: AOJu0YxasAWmUCIu7XaUP0XMW3l8XqHhCQx+llpeMOSk+CIaoDPleY/E qcxSWiHvTrky9ASZJc+rqbET9QYoOQE7m4mM1z8TsMS3BlHMxz66xKKc3bheZu8kXZ4mA6W3X2L 31aeKIL1v4tx/LsKnOnbs5LBTzg== X-Received: from pga26.prod.google.com ([2002:a05:6a02:4f9a:b0:c79:8685:ebfc]) (user=joonwonkang job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:7285:b0:39f:27ab:2454 with SMTP id adf61e73a8af0-3a08d90d557mr19311506637.49.1776768418015; Tue, 21 Apr 2026 03:46:58 -0700 (PDT) Date: Tue, 21 Apr 2026 10:46:51 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.54.0.rc1.555.g9c883467ad-goog Message-ID: <20260421104652.211276-1-joonwonkang@google.com> Subject: [PATCH] mailbox: Clarify multi-thread is not supported in blocking mode From: Joonwon Kang To: jassisinghbrar@gmail.com, sudeep.holla@kernel.org Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, akpm@linux-foundation.org, Joonwon Kang Content-Type: text/plain; charset="UTF-8" Unlike in non-blocking mode, multi-thread has not been supported in blocking mode. This commit is to prevent clients from having wrong assumption by explicitly specifying this fact to the API doc. Cc: stable@vger.kernel.org Signed-off-by: Joonwon Kang --- v1: Abandon the previous attempts to support multi-thread in blocking mode and instead declare it is not supported. drivers/mailbox/mailbox.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c index bbc9fd75a95f..b00f7a32e866 100644 --- a/drivers/mailbox/mailbox.c +++ b/drivers/mailbox/mailbox.c @@ -258,6 +258,10 @@ EXPORT_SYMBOL_GPL(mbox_chan_tx_slots_available); * over the chan, i.e, tx_done() is made. * This function could be called from atomic context as it simply * queues the data and returns a token against the request. + * In blocking mode, it is caller's responsibility to serialize threads' + * access to a channel if multi-threads are to send messages through the + * same channel, i.e. caller should not call this function until any + * previous call returns. * * Return: Non-negative integer for successful submission (non-blocking mode) * or transmission over chan (blocking mode). -- 2.54.0.rc1.555.g9c883467ad-goog