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 6DE1317CA12; Wed, 19 Feb 2025 22:31:45 +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=1740004305; cv=none; b=vGgJNUuyoszutSECIstVETCM+ygILdnQGK3Ph380IF5qESqvjY8XbOXL1KUdJuTGtZSv69+y2nwpbHd+B+8+z4YFkiXV82Bcs7Ppx8atPVq9b64vCMchlev3jHVnlCzlqaLsDRHgPue5IMP5SrS3wi52GxMpH0EoQrOUSYx6blg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740004305; c=relaxed/simple; bh=rjSUNO4FBfyczkNOrpnaKO1/3mMyZPB4f6E+zbJobb4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=m8Sow1k3eK0Edk+4uss0DhDqoZrMpC7gRu2AqOSUugOHCtVnq4Jd3zddT5Zeh9sqDRL1SADzagzSwdC/0NeL7U3f2Zwewa11NVNvrmq38zugPEPVY4eqVG+4Ei2vTQJDQoZ0r9VObWhV0Vd+mLqzwer5sP6GNmYzRk7HhAm1r6U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D/U0cIbG; 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="D/U0cIbG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E6AC5C4CED1; Wed, 19 Feb 2025 22:31:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740004305; bh=rjSUNO4FBfyczkNOrpnaKO1/3mMyZPB4f6E+zbJobb4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=D/U0cIbGvZlIIdF7wVL4bdsv01qrfUlAkE7buOO/aiDblUfGUkFm4kubdK65pQF1n vUtQjjky8XwFQDLmVbaFOF9mSto67WKF5s0JfhpZ0gXWVALaz2o8p5xvZLRgG/M5c2 qv5KjecULUorrDFpoHa3rNVjOUeRMru2XO48DfcGK6L5qQephYhdNBdsNCEvfZMPME HRO7E6W8/vDpCPISAgnmyIgW+8Dc75CIqI9GRC+hwC7ccHVgdo/BJO/3/ec5m95iu0 9H1KiP+G85k2mCBu0K6DLlheKS648u/v5QevgHJQbr2MWIV1/1hjCbMya32UHOQpNa Pw/zZZl+WUaRw== Date: Wed, 19 Feb 2025 14:31:44 -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: <20250219223144.GH21808@frogsfrogsfrogs> References: <20250219175050.83986-1-bfoster@redhat.com> <20250219175050.83986-2-bfoster@redhat.com> <20250219222235.GB21808@frogsfrogsfrogs> 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: <20250219222235.GB21808@frogsfrogsfrogs> On Wed, Feb 19, 2025 at 02:22:35PM -0800, Darrick J. Wong wrote: > 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? And that's provided in the last patch so Reviewed-by: "Darrick J. Wong" --D > > --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 > > > > >