From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Date: Fri, 23 Dec 2022 07:07:38 -0800 Subject: [Cluster-devel] [RFC v3 5/7] iomap: Get page in page_prepare handler In-Reply-To: <20221216150626.670312-6-agruenba@redhat.com> References: <20221216150626.670312-1-agruenba@redhat.com> <20221216150626.670312-6-agruenba@redhat.com> Message-ID: List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, Dec 16, 2022 at 04:06:24PM +0100, Andreas Gruenbacher wrote: > Change the iomap ->page_prepare() handler to get and return a locked > folio instead of doing that in iomap_write_begin(). This allows to > recover from out-of-memory situations in ->page_prepare(), which > eliminates the corresponding error handling code in iomap_write_begin(). > The ->page_done() handler is now not called with a NULL folio anymore. Ah, okay - this is the other half of what I asked for earlier, so we're aligned. Sorry for the noise earlier. I'd still prefer the naming I suggest, though. > + if (page_ops && page_ops->page_prepare) > + folio = page_ops->page_prepare(iter, pos, len); > + else > + folio = iomap_folio_prepare(iter, pos); > + if (IS_ERR_OR_NULL(folio)) { > + if (!folio) > + return (iter->flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOMEM; > + return PTR_ERR(folio); > } Maybe encapsulate this in a iomap_get_folio wrapper just to keep the symmetry with the done side.