From c450846461f88b8888d6f5c2a2aa63ab64864978 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 6 Feb 2020 14:22:28 +0000 Subject: afs: Set up the iov_iter before calling afs_extract_data() afs_extract_data() sets up a temporary iov_iter and passes it to AF_RXRPC each time it is called to describe the remaining buffer to be filled. Instead: (1) Put an iterator in the afs_call struct. (2) Set the iterator for each marshalling stage to load data into the appropriate places. A number of convenience functions are provided to this end (eg. afs_extract_to_buf()). This iterator is then passed to afs_extract_data(). (3) Use the new ITER_XARRAY iterator when reading data to load directly into the inode's pages without needing to create a list of them. This will allow O_DIRECT calls to be supported in future patches. Signed-off-by: David Howells Tested-By: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/152898380012.11616.12094591785228251717.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/153685394431.14766.3178466345696987059.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/153999787395.866.11218209749223643998.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/154033911195.12041.3882700371848894587.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/158861250059.340223.1248231474865140653.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465827399.1377938.11181327349704960046.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588533776.3465195.3612752083351956948.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118151238.1232039.17015723405750601161.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161047240.2537118.14721975104810564022.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340410333.1303470.16260122230371140878.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539554187.286939.15305559004905459852.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653810525.2770958.4630666029125411789.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789093719.6155.7877160739235087723.stgit@warthog.procyon.org.uk/ # v6 --- fs/afs/write.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) (limited to 'fs/afs/write.c') diff --git a/fs/afs/write.c b/fs/afs/write.c index a91da2e680da..cb24f849e592 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -22,6 +22,16 @@ int afs_set_page_dirty(struct page *page) return __set_page_dirty_nobuffers(page); } +/* + * Handle completion of a read operation to fill a page. + */ +static void afs_fill_hole(struct afs_read *req) +{ + if (iov_iter_count(req->iter) > 0) + /* The read was short - clear the excess buffer. */ + iov_iter_zero(iov_iter_count(req->iter), req->iter); +} + /* * partly or wholly fill a page that's under preparation for writing */ @@ -45,18 +55,19 @@ static int afs_fill_page(struct file *file, return 0; } - req = kzalloc(struct_size(req, array, 1), GFP_KERNEL); + req = kzalloc(sizeof(struct afs_read), GFP_KERNEL); if (!req) return -ENOMEM; refcount_set(&req->usage, 1); - req->key = key_get(afs_file_key(file)); - req->pos = pos; - req->len = len; - req->nr_pages = 1; - req->pages = req->array; - req->pages[0] = page; - get_page(page); + req->vnode = vnode; + req->done = afs_fill_hole; + req->key = key_get(afs_file_key(file)); + req->pos = pos; + req->len = len; + req->nr_pages = 1; + req->iter = &req->def_iter; + iov_iter_xarray(&req->def_iter, READ, &file->f_mapping->i_pages, pos, len); ret = afs_fetch_data(vnode, req); afs_put_read(req); -- cgit v1.2.3