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bh=49IJ7O8KaG9bUjSCVtwVGeadJYJCODKyAnH6L7XF9aY=; b=DuYxIo6R/2/t+ljWYuwfegE73eHF5TDxIlwApqrLYn9UyolK3D9znLjqytYI1dRDwEcBZu PwE4pQSW9sgWnrWUnREVpj2uqgnbvKsCCOCosqL+l8o7FsRw+nskfUDswYk01axIEsbg29 K7YWiXOXJqEvDXVbBLwEpwQy43CScHQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-443-1yMYszxON0mvnfJn-xDpZA-1; Mon, 13 Feb 2023 10:33:17 -0500 X-MC-Unique: 1yMYszxON0mvnfJn-xDpZA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0864D18A6464; Mon, 13 Feb 2023 15:33:17 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1696CC16022; Mon, 13 Feb 2023 15:33:14 +0000 (UTC) From: David Howells To: Jens Axboe , Al Viro , Christoph Hellwig Cc: David Howells , Matthew Wilcox , Jan Kara , Jeff Layton , David Hildenbrand , Jason Gunthorpe , Logan Gunthorpe , Hillf Danton , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Hellwig , John Hubbard Subject: [PATCH v2 4/4] splice: Move filemap_read_splice() to mm/filemap.c Date: Mon, 13 Feb 2023 15:33:01 +0000 Message-Id: <20230213153301.2338806-5-dhowells@redhat.com> In-Reply-To: <20230213153301.2338806-1-dhowells@redhat.com> References: <20230213153301.2338806-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: 7hoqaq3dunz4nj1j3ieyoz1xqad6h4i6 X-Rspamd-Queue-Id: E0D7440016 X-HE-Tag: 1676302401-599231 X-HE-Meta: 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 MFstJ10T 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Move filemap_read_splice() to mm/filemap.c and make filemap_get_pages() static again. Requested-by: Christoph Hellwig Signed-off-by: David Howells Reviewed-by: Christoph Hellwig cc: Jens Axboe cc: Al Viro cc: John Hubbard cc: David Hildenbrand cc: Matthew Wilcox cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org Reviewed-by: David Hildenbrand --- fs/splice.c | 127 ------------------------------------- include/linux/pagemap.h | 2 - include/linux/splice.h | 4 ++ mm/filemap.c | 137 ++++++++++++++++++++++++++++++++++++++-- 4 files changed, 135 insertions(+), 135 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 4ea63d6a9040..341cd8fb47a8 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -375,133 +375,6 @@ static ssize_t direct_splice_read(struct file *in, loff_t *ppos, return ret; } -/* - * Splice subpages from a folio into a pipe. - */ -static size_t splice_folio_into_pipe(struct pipe_inode_info *pipe, - struct folio *folio, - loff_t fpos, size_t size) -{ - struct page *page; - size_t spliced = 0, offset = offset_in_folio(folio, fpos); - - page = folio_page(folio, offset / PAGE_SIZE); - size = min(size, folio_size(folio) - offset); - offset %= PAGE_SIZE; - - while (spliced < size && - !pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { - struct pipe_buffer *buf = pipe_head_buf(pipe); - size_t part = min_t(size_t, PAGE_SIZE - offset, size - spliced); - - *buf = (struct pipe_buffer) { - .ops = &page_cache_pipe_buf_ops, - .page = page, - .offset = offset, - .len = part, - }; - folio_get(folio); - pipe->head++; - page++; - spliced += part; - offset = 0; - } - - return spliced; -} - -/* - * Splice folios from the pagecache of a buffered (ie. non-O_DIRECT) file into - * a pipe. - */ -static ssize_t filemap_splice_read(struct file *in, loff_t *ppos, - struct pipe_inode_info *pipe, - size_t len, unsigned int flags) -{ - struct folio_batch fbatch; - struct kiocb iocb; - size_t total_spliced = 0, used, npages; - loff_t isize, end_offset; - bool writably_mapped; - int i, error = 0; - - init_sync_kiocb(&iocb, in); - iocb.ki_pos = *ppos; - - /* Work out how much data we can actually add into the pipe */ - used = pipe_occupancy(pipe->head, pipe->tail); - npages = max_t(ssize_t, pipe->max_usage - used, 0); - len = min_t(size_t, len, npages * PAGE_SIZE); - - folio_batch_init(&fbatch); - - do { - cond_resched(); - - if (*ppos >= i_size_read(file_inode(in))) - break; - - iocb.ki_pos = *ppos; - error = filemap_get_pages(&iocb, len, &fbatch, true); - if (error < 0) - break; - - /* - * i_size must be checked after we know the pages are Uptodate. - * - * Checking i_size after the check allows us to calculate - * the correct value for "nr", which means the zero-filled - * part of the page is not copied back to userspace (unless - * another truncate extends the file - this is desired though). - */ - isize = i_size_read(file_inode(in)); - if (unlikely(*ppos >= isize)) - break; - end_offset = min_t(loff_t, isize, *ppos + len); - - /* - * Once we start copying data, we don't want to be touching any - * cachelines that might be contended: - */ - writably_mapped = mapping_writably_mapped(in->f_mapping); - - for (i = 0; i < folio_batch_count(&fbatch); i++) { - struct folio *folio = fbatch.folios[i]; - size_t n; - - if (folio_pos(folio) >= end_offset) - goto out; - folio_mark_accessed(folio); - - /* - * If users can be writing to this folio using arbitrary - * virtual addresses, take care of potential aliasing - * before reading the folio on the kernel side. - */ - if (writably_mapped) - flush_dcache_folio(folio); - - n = splice_folio_into_pipe(pipe, folio, *ppos, len); - if (!n) - goto out; - len -= n; - total_spliced += n; - *ppos += n; - in->f_ra.prev_pos = *ppos; - if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) - goto out; - } - - folio_batch_release(&fbatch); - } while (len); - -out: - folio_batch_release(&fbatch); - file_accessed(in); - - return total_spliced ? total_spliced : error; -} - /** * generic_file_splice_read - splice data from file to a pipe * @in: file to splice from diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 3a7bdb35acff..29e1f9e76eb6 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -748,8 +748,6 @@ struct page *read_cache_page(struct address_space *, pgoff_t index, filler_t *filler, struct file *file); extern struct page * read_cache_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp_mask); -int filemap_get_pages(struct kiocb *iocb, size_t count, - struct folio_batch *fbatch, bool need_uptodate); static inline struct page *read_mapping_page(struct address_space *mapping, pgoff_t index, struct file *file) diff --git a/include/linux/splice.h b/include/linux/splice.h index a55179fd60fc..691c44ef5c0b 100644 --- a/include/linux/splice.h +++ b/include/linux/splice.h @@ -67,6 +67,10 @@ typedef int (splice_actor)(struct pipe_inode_info *, struct pipe_buffer *, typedef int (splice_direct_actor)(struct pipe_inode_info *, struct splice_desc *); +ssize_t filemap_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, + size_t len, unsigned int flags); + extern ssize_t splice_from_pipe(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int, splice_actor *); diff --git a/mm/filemap.c b/mm/filemap.c index 6970be64a3e0..e1ee267675d2 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -42,6 +42,8 @@ #include #include #include +#include +#include #include #include #include "internal.h" @@ -2576,12 +2578,8 @@ static int filemap_readahead(struct kiocb *iocb, struct file *file, return 0; } -/* - * Extract some folios from the pagecache of a file, reading those pages from - * the backing store if necessary and waiting for them. - */ -int filemap_get_pages(struct kiocb *iocb, size_t count, - struct folio_batch *fbatch, bool need_uptodate) +static int filemap_get_pages(struct kiocb *iocb, size_t count, + struct folio_batch *fbatch, bool need_uptodate) { struct file *filp = iocb->ki_filp; struct address_space *mapping = filp->f_mapping; @@ -2845,6 +2843,133 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) } EXPORT_SYMBOL(generic_file_read_iter); +/* + * Splice subpages from a folio into a pipe. + */ +static size_t splice_folio_into_pipe(struct pipe_inode_info *pipe, + struct folio *folio, + loff_t fpos, size_t size) +{ + struct page *page; + size_t spliced = 0, offset = offset_in_folio(folio, fpos); + + page = folio_page(folio, offset / PAGE_SIZE); + size = min(size, folio_size(folio) - offset); + offset %= PAGE_SIZE; + + while (spliced < size && + !pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { + struct pipe_buffer *buf = pipe_head_buf(pipe); + size_t part = min_t(size_t, PAGE_SIZE - offset, size - spliced); + + *buf = (struct pipe_buffer) { + .ops = &page_cache_pipe_buf_ops, + .page = page, + .offset = offset, + .len = part, + }; + folio_get(folio); + pipe->head++; + page++; + spliced += part; + offset = 0; + } + + return spliced; +} + +/* + * Splice folios from the pagecache of a buffered (ie. non-O_DIRECT) file into + * a pipe. + */ +ssize_t filemap_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, + size_t len, unsigned int flags) +{ + struct folio_batch fbatch; + struct kiocb iocb; + size_t total_spliced = 0, used, npages; + loff_t isize, end_offset; + bool writably_mapped; + int i, error = 0; + + init_sync_kiocb(&iocb, in); + iocb.ki_pos = *ppos; + + /* Work out how much data we can actually add into the pipe */ + used = pipe_occupancy(pipe->head, pipe->tail); + npages = max_t(ssize_t, pipe->max_usage - used, 0); + len = min_t(size_t, len, npages * PAGE_SIZE); + + folio_batch_init(&fbatch); + + do { + cond_resched(); + + if (*ppos >= i_size_read(file_inode(in))) + break; + + iocb.ki_pos = *ppos; + error = filemap_get_pages(&iocb, len, &fbatch, true); + if (error < 0) + break; + + /* + * i_size must be checked after we know the pages are Uptodate. + * + * Checking i_size after the check allows us to calculate + * the correct value for "nr", which means the zero-filled + * part of the page is not copied back to userspace (unless + * another truncate extends the file - this is desired though). + */ + isize = i_size_read(file_inode(in)); + if (unlikely(*ppos >= isize)) + break; + end_offset = min_t(loff_t, isize, *ppos + len); + + /* + * Once we start copying data, we don't want to be touching any + * cachelines that might be contended: + */ + writably_mapped = mapping_writably_mapped(in->f_mapping); + + for (i = 0; i < folio_batch_count(&fbatch); i++) { + struct folio *folio = fbatch.folios[i]; + size_t n; + + if (folio_pos(folio) >= end_offset) + goto out; + folio_mark_accessed(folio); + + /* + * If users can be writing to this folio using arbitrary + * virtual addresses, take care of potential aliasing + * before reading the folio on the kernel side. + */ + if (writably_mapped) + flush_dcache_folio(folio); + + n = splice_folio_into_pipe(pipe, folio, *ppos, len); + if (!n) + goto out; + len -= n; + total_spliced += n; + *ppos += n; + in->f_ra.prev_pos = *ppos; + if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) + goto out; + } + + folio_batch_release(&fbatch); + } while (len); + +out: + folio_batch_release(&fbatch); + file_accessed(in); + + return total_spliced ? total_spliced : error; +} + static inline loff_t folio_seek_hole_data(struct xa_state *xas, struct address_space *mapping, struct folio *folio, loff_t start, loff_t end, bool seek_data)