From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C0800286280; Wed, 19 Feb 2025 22:22:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740003756; cv=none; b=AYAXPiRxaRLrBz4BBkTfuURbeBOAqWhYEIOnXhMntgVXgqLtKu8yoG04qsLsmy1X3A8nx4U8OcK/v9a8b/uHNSBzGBqhWfU8YR+3sAiYb334fazbazoJLkiIAHKz9OYpKiDzAtMfyukkOpMHj83X9AlEVTceFELiMmktLzScYMs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740003756; c=relaxed/simple; bh=SutIu3Ft66646WwIdiUf9XX7kwLKS5b0/THMrNij154=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=iWB2I1W6f55gkf9gjt5ex9AsqBGUJ12PDJbVnLwYok2ToKTu0h/XZ4WeLUQjHV9zNMXG+dEqdq/I7xxivOT6vKljgiu2VaJqweuatiqB8MuE86I6fdn3yQPn/t1x1HxflMF2ml/TljbWwNHePKYn2vAB3On4tJwHxSdYnyTJap8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QjaRJYTz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QjaRJYTz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3701FC4CED1; Wed, 19 Feb 2025 22:22:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740003756; bh=SutIu3Ft66646WwIdiUf9XX7kwLKS5b0/THMrNij154=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QjaRJYTzL4nrxje5CL7mkYTi8EhO80WJ/4SUIDrfkN+snUjwMl61SjSTPSG6XW3Qm zR/aui7wFk/dTZYyx3h4/l+ZL8cPrx5bXhagZ1hEmeBRa2zkRVZoUkXxOt7cSvAZTW PTvwEugHQDgkVVm7Ez9Duuqt/64aA0ExTCxzZE73WdOhe0gQ0kr6BAS7jj+Yg1vO0W 3ul6UMTtsbjUrW20AYYgY/ZP+rFx3lX+GxqKUuxqVam3wwfoKKze6E73MBS2yxqERc 0nBGOvSoyM7cle9YsngvwwBMrgyjatXfIKw7WS5Dj6ANmqQiS0qyTzQksXcCbVPYnf tWhNGRvmSW0Fw== Date: Wed, 19 Feb 2025 14:22:35 -0800 From: "Darrick J. Wong" To: Brian Foster Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, Christoph Hellwig Subject: Re: [PATCH v2 01/12] iomap: advance the iter directly on buffered read Message-ID: <20250219222235.GB21808@frogsfrogsfrogs> References: <20250219175050.83986-1-bfoster@redhat.com> <20250219175050.83986-2-bfoster@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250219175050.83986-2-bfoster@redhat.com> On Wed, Feb 19, 2025 at 12:50:39PM -0500, Brian Foster wrote: > iomap buffered read advances the iter via iter.processed. To > continue separating iter advance from return status, update > iomap_readpage_iter() to advance the iter instead of returning the > number of bytes processed. In turn, drop the offset parameter and > sample the updated iter->pos at the start of the function. Update > the callers to loop based on remaining length in the current > iteration instead of number of bytes processed. > > Signed-off-by: Brian Foster > Reviewed-by: Christoph Hellwig > --- > fs/iomap/buffered-io.c | 45 +++++++++++++++++++----------------------- > 1 file changed, 20 insertions(+), 25 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index ec227b45f3aa..215866ba264d 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -366,15 +366,14 @@ static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter, > pos >= i_size_read(iter->inode); > } > > -static loff_t iomap_readpage_iter(const struct iomap_iter *iter, > - struct iomap_readpage_ctx *ctx, loff_t offset) > +static loff_t iomap_readpage_iter(struct iomap_iter *iter, I wonder, do we really need to return loff_t from some of these functions now? I thought the only return codes were the -EIO/0 from iomap_iter_advance? --D > + struct iomap_readpage_ctx *ctx) > { > const struct iomap *iomap = &iter->iomap; > - loff_t pos = iter->pos + offset; > - loff_t length = iomap_length(iter) - offset; > + loff_t pos = iter->pos; > + loff_t length = iomap_length(iter); > struct folio *folio = ctx->cur_folio; > struct iomap_folio_state *ifs; > - loff_t orig_pos = pos; > size_t poff, plen; > sector_t sector; > > @@ -438,25 +437,22 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter, > * we can skip trailing ones as they will be handled in the next > * iteration. > */ > - return pos - orig_pos + plen; > + length = pos - iter->pos + plen; > + return iomap_iter_advance(iter, &length); > } > > -static loff_t iomap_read_folio_iter(const struct iomap_iter *iter, > +static loff_t iomap_read_folio_iter(struct iomap_iter *iter, > struct iomap_readpage_ctx *ctx) > { > - struct folio *folio = ctx->cur_folio; > - size_t offset = offset_in_folio(folio, iter->pos); > - loff_t length = min_t(loff_t, folio_size(folio) - offset, > - iomap_length(iter)); > - loff_t done, ret; > - > - for (done = 0; done < length; done += ret) { > - ret = iomap_readpage_iter(iter, ctx, done); > - if (ret <= 0) > + loff_t ret; > + > + while (iomap_length(iter)) { > + ret = iomap_readpage_iter(iter, ctx); > + if (ret) > return ret; > } > > - return done; > + return 0; > } > > int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) > @@ -493,15 +489,14 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) > } > EXPORT_SYMBOL_GPL(iomap_read_folio); > > -static loff_t iomap_readahead_iter(const struct iomap_iter *iter, > +static loff_t iomap_readahead_iter(struct iomap_iter *iter, > struct iomap_readpage_ctx *ctx) > { > - loff_t length = iomap_length(iter); > - loff_t done, ret; > + loff_t ret; > > - for (done = 0; done < length; done += ret) { > + while (iomap_length(iter)) { > if (ctx->cur_folio && > - offset_in_folio(ctx->cur_folio, iter->pos + done) == 0) { > + offset_in_folio(ctx->cur_folio, iter->pos) == 0) { > if (!ctx->cur_folio_in_bio) > folio_unlock(ctx->cur_folio); > ctx->cur_folio = NULL; > @@ -510,12 +505,12 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter, > ctx->cur_folio = readahead_folio(ctx->rac); > ctx->cur_folio_in_bio = false; > } > - ret = iomap_readpage_iter(iter, ctx, done); > - if (ret <= 0) > + ret = iomap_readpage_iter(iter, ctx); > + if (ret) > return ret; > } > > - return done; > + return 0; > } > > /** > -- > 2.48.1 > >