From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 906CF38F249; Wed, 30 Sep 2026 19:44:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790797461; cv=none; b=RZ82BSLaRu2cH+owV992iOSmKy7CjSLmKbzoOR6TMCZTaRpk0NkvzY/RgqF/+7b02jcS1hHbSVbzm7IHXpikjZLhXQrbizZOOMU72b8My64t4PHy91QZ5WyPAi51JEmUnEZR1Qu4ln0XdjpSX/kAnsFT8un7oOx0Sxy/THwFX5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790797461; c=relaxed/simple; bh=leG+KYeMecwefNn3L8fO7Ys/JSrQICGvkRv9x3AvfgE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=CAp3oRyVv/+BMSxlm2BCMrUd8V/XAYfIU9u+0i7EkSbcpyfG8U10Ry0yzuqFTa+OtKkTfs7LeT1AzaCSJODXzjq5sZbdfS7b8zjtqHRajmaeH4fKKRzY+Gc2T1RUpne5KZpBK0CVxj1+cx3bF72zWOt1RxibadKfyEHGP5oDM6Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LPNkegk9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LPNkegk9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4431D1F000FF; Wed, 30 Sep 2026 19:44:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790797460; bh=OFImjkr9ZJupqvHYnBoqpp0icOp41KnUwRZeP8bQc5I=; h=From:Date:Subject:To:Cc; b=LPNkegk9RXC05RGxdiAl4ldyTuAeoeyViY0lP+p34gdbBl6CcI6PNu7f6q08ghDGT NL6rN8YsDe3YEcIxBxUO2jbgoMw0egQzmF7ivQ1EsvMEM427qqQgVhUBUdRvRnfba2 TbtLNRUgZ3EkmHvOw0OBcKYpsDacdqFZB9jZt1KapL+pQurYP4icnrZZsw9XB+PRRd ZNBX78lSQK6Ejg3Oa9febQIigI5NvUi+nCDRLvQYZYmZzZj/Wo9299VkUlqbCOWB31 Si/D3X+k5HrfBpz+YyqjtATXApXhN8ZaA8P0e6fQufzNRNq9C6/Y549/CF1Roma6O8 NCtVUK0gQzTEw== From: Andreas Hindborg Date: Wed, 30 Sep 2026 21:43:55 +0200 Subject: [PATCH] rust: block: implement `Send` and `Sync` for `TagSet` Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260930-tag-set-send-sync-v1-1-51acdb36f4bb@kernel.org> X-B4-Tracking: v=1; b=H4sIAHpmvWoC/yXMMQ6DMBBE0augrVnJJoAEV4koiD0hm8JEXoMSI e6OIcUUr5i/kSIKlPpio4hVVOaQYcuC3GsME1h8NlWmak13M5zGiRUpL3jWX3Dsat/WjW1gYSj /PhFP+V7N+/C3Lo83XDpDtO8HiZZuRnUAAAA= X-Change-ID: 20260930-tag-set-send-sync-c4d64515e1e0 To: Jens Axboe Cc: Thorsten Leemhuis , Boqun Feng , Miguel Ojeda , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , =?utf-8?q?Onur_=C3=96zkan?= , linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Hindborg X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2010; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=leG+KYeMecwefNn3L8fO7Ys/JSrQICGvkRv9x3AvfgE=; b=owEBbQKS/ZANAwAKAfpQKQiqxb3QAcsmYgBqvWaAXiJhiIrfd2oNYRlrnpRfVkoC3C6m8r4DH VY6XRN7LkyJAjMEAAEKAB0WIQRXitnI2WZ2JirAaob6UCkIqsW90AUCar1mgAAKCRD6UCkIqsW9 0JYED/4n5gj6Blm4y7ot1QcNTsHXJ+I1rgKjbWpH2WbtKyBSUTjmHFwJ68YPJ2C58FfNE3yntOy FS6FkfYYmt40M5KXL9Fg1ZAwKEBWIQdYAM0SFWc1ZzorNBEgxqzZDfnL19TB562O/zoUEwhe7fY Ru9jbfOeRKTiQviVkd1uiN9zA+i0KXoStglEgoceL4u15dBqeGaBkV6GSpkH17l4AqzL7K/tOQW kpAWqH0GooXvncxrRwsHMKZptJqd5R5745Z1A7Ge6WjTzLam1uV2y3jJsATizbtH44jrtwRs+gw 2VzxfEZneBnoTIEperYhFc7WrPS8l74A0yV9CM8nvkRwNu0NTn6ysVosxeornosqhKF1qrjfh3X umXd4lmvkgVDvxsjd5PUBd6yjj+ssQV0tsACJ48/jCTgyR5GeDW8dDSGAtM9YHZTTW6FlpSQqQi fGyla98K74N5YrXBJrZ6ykT1YeI9Y+kwuVOjCKhEJ4XkXBD/nGbvhkZQ5NhkMBHKN/YbaBM0Ayu /OFiMupuwKTbNFGhUrp3Pz+JLne7QIFXt5PZ1yjOIidTorLoUiv0jmDdmzr/IF/K3Gtoeu6F8op 8EkVV8kexsffyfv1LibkAdRdiS3g2bTNtsSrjjAwuQP0QtkHlZySVeinvN18xYpH7iF4UWmlKIP aOGYoMqmsdCbytA== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 `TagSet` never implemented `Send` or `Sync`. This did not matter until commit "rust: block: fix `Send` bound for `GenDisk`" made `GenDisk: Send` depend on `Arc>: Send`, which in turn requires `TagSet: Send + Sync`. With that bound unsatisfiable, `GenDisk` is never `Send`, and the rnull driver fails to build once configfs requires `GroupOperations::Child: Send`. `TagSet` owns no data typed by `T`. It only wraps the C `struct blk_mq_tag_set`, which can be dropped from any thread by calling `blk_mq_free_tag_set`. Thus, implement `Send` and `Sync` for `TagSet` unconditionally. Reported-by: Thorsten Leemhuis Closes: https://lore.kernel.org/r/d1381ed8-eab8-4fd7-8b15-1e94876d7099@leemhuis.info Suggested-by: Gary Guo Signed-off-by: Andreas Hindborg --- Hi Jens, Please pick this patch to resolve a problematic rust configfs/block interaction in linux-next [1]. Best regards, Andreas Hindborg [1] https://lore.kernel.org/r/d1381ed8-eab8-4fd7-8b15-1e94876d7099@leemhuis.info --- rust/kernel/block/mq/tag_set.rs | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs index dae9df408a86..00d29688f920 100644 --- a/rust/kernel/block/mq/tag_set.rs +++ b/rust/kernel/block/mq/tag_set.rs @@ -83,3 +83,10 @@ fn drop(self: Pin<&mut Self>) { unsafe { bindings::blk_mq_free_tag_set(self.inner.get()) }; } } + +// SAFETY: It is safe to transfer ownership of `TagSet` between threads. +unsafe impl Send for TagSet {} + +// SAFETY: It is safe to share `&TagSet` across threads. `TagSet` exposes no +// `&self` methods that mutate the contained `blk_mq_tag_set`. +unsafe impl Sync for TagSet {} --- base-commit: df2908090cda368b01ff43709f51890076c56157 change-id: 20260930-tag-set-send-sync-c4d64515e1e0 Best regards, -- Andreas Hindborg