From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f73.google.com (mail-dl1-f73.google.com [74.125.82.73]) (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 61F7F1FECAB for ; Fri, 8 May 2026 01:54:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778205266; cv=none; b=eiY1fl/uPQ0TeR3nmMHs/UQ5VPDExniYdxofSie2t/+IMX/K30kXM/X1EcWPdAAkSTVK+2ooFTHdZcWB1SK/ci7j+GHDRfN9zo6K3anSdHX2rQalJ0enDWwbfdBMBZtDqfyetcDGArX0AsgJFem7I6HDe55A2pc7tNyxkNk9OQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778205266; c=relaxed/simple; bh=JvbD0U0T+bhy9IJj6fXaNvDa29+thTK1djpSTzYkHgw=; h=Date:Mime-Version:Message-ID:Subject:From:Cc:Content-Type; b=JeAu10WOx+c4FFWrHOppcoJqo3tLDQ1TCfJiV1+gfnyqxi0d2BCLr7LutG1xa2lrPKWuEJ9WKiNECuQCi1bDs5HrQWItTDaTbwSbvhyfKAjRFf3Yhm0LCPdgdye6oPCVqjMKOi4EMPUrdjanssOCH1rWQwcEwCTIaidgjvU0WRw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--fmayle.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=DH9fQ94j; arc=none smtp.client-ip=74.125.82.73 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--fmayle.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="DH9fQ94j" Received: by mail-dl1-f73.google.com with SMTP id a92af1059eb24-12dc3d81736so1674551c88.1 for ; Thu, 07 May 2026 18:54:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1778205264; x=1778810064; darn=vger.kernel.org; h=cc:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=nDCNoZ6k2LKNRaJd57QrXwFLyWNzjd5ZsttzB1Naw58=; b=DH9fQ94j/vmH8gtjjZEEozd4FIP8es8vfu6caveYEJOARiW/TkWe3r6Wp4CjXL4LZ1 sYwQHxQ4J2cXHFZt5trf6w27XkfyMdmQJFIM1qV2/dWD7oEsATVSo/qlbhvlpcjYeg/O pTvs3F+mKYfIbFSqv1V+Nsu1S4XFFkiUZ57sVZs0Ksaoz+9UZz2eheV1saZdA77+XGxS Rnvx9Kt7knMCMiwW4Y8ZyF9ESQ2KKF/z4PUonyvghAFqWqr9NN6ymmdlyZxvvyHUafuw HpE/7NhyIR9habje65gdGWufBCDoJHf/OkfJbTYDtL70t5Ig7cJvIdlSIymoWCmc7tmk UWYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778205264; x=1778810064; h=cc:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=nDCNoZ6k2LKNRaJd57QrXwFLyWNzjd5ZsttzB1Naw58=; b=nTL6vzyRxChNmQW1ojnOrSAf+dD872ZjzuwZgXzRqg4QSX3BdH4a838oO+/7Qb4XZ3 Sv7bXYzFPPwYK+S4pmMHRgyoSPOx29BV3iIQIRdWQ/0RQF5ZFgKH2S7orag4HBoXR9Lr 8dtX7YjwG0yZpri3j55TPlmpZ7RLR6scDjHc+0HAXrnPo3whYZZz47IqEQ0Cf8M+h3yf OjxOYaWZs1bNlmKZjB2IXh4gH/boc24onfSmHIpYwa93l9Tawdt52A+xm6cLnQwmqZxV XLd71W3IBKPPKx2siMg1e483CkBEGlvjxykrn//ZvGlYg9lbzDzB+Zy1aqo/YWBZyp0u 3Lkw== X-Forwarded-Encrypted: i=1; AFNElJ9R9ba5tGf4jMjwc97NbCNYMMOYVZczFxVegD2YSZRSQdZCJ4WiC3e8XG5VeXSO/ri9xHpYIJ7Pw5cgTUQ=@vger.kernel.org X-Gm-Message-State: AOJu0YxsVHCa26cYqS6P/4NS9H2ZsVoBKN38dHFnB4ym/ULvcgGSwWMp 8gv/m403UoO+ikdSJGQW1l/fInIDUi7cdhV0UzGqS0LZkIpbFZU6HpT6dzfzU7WtfYnjFrKfluK wnN973A== X-Received: from dlbep12.prod.google.com ([2002:a05:7022:108c:b0:12d:c585:f600]) (user=fmayle job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:7a6:b0:128:d9a1:b68b with SMTP id a92af1059eb24-131a69ece6bmr5011504c88.33.1778205263925; Thu, 07 May 2026 18:54:23 -0700 (PDT) Date: Thu, 7 May 2026 18:53:57 -0700 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 2.54.0.563.g4f69b47b94-goog Message-ID: <20260508015402.735441-1-fmayle@google.com> Subject: [PATCH 1/1] mm/readahead: add kerneldoc for read_pages From: Frederick Mayle Cc: android-mm@google.com, kernel-team@android.com, Frederick Mayle , Andrew Morton , "Matthew Wilcox (Oracle)" , Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Formalize one of the invariants provided by the current implementation so that callers can depend on it, as discussed in [1]. Link: https://lore.kernel.org/all/20260501061146.6e61392d125cf1847d7cc181@linux-foundation.org/ [1] Cc: Andrew Morton Signed-off-by: Frederick Mayle --- mm/readahead.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/readahead.c b/mm/readahead.c index 8c12b63ccd4a..23bec5497308 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -146,6 +146,17 @@ file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping) } EXPORT_SYMBOL_GPL(file_ra_state_init); +/** + * read_pages() - Start IO for a contiguous range of allocated folios in the + * page cache. + * @rac: Readahead control. + * + * When read_pages() returns, it is guaranteed that all of the folios will have + * been processed or removed so that ``readahead_count(rac) == 0``. However, + * that does not imply that ``readahead_index(rac)`` will be updated to point + * to the end of the originally requested range because, for example, the + * filesystem may expand the range upwards. + */ static void read_pages(struct readahead_control *rac) { const struct address_space_operations *aops = rac->mapping->a_ops; base-commit: 2d565cbaafd43b10b75da56e43e5db9852a56afd -- 2.54.0.563.g4f69b47b94-goog