2023-01-19 22:03:47

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v2 03/18] NFS: Support folios in nfs_generic_pgio()

From: Trond Myklebust <[email protected]>

Add support for multi-page folios in the generic NFS i/o engine.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/internal.h | 7 +++--
fs/nfs/pagelist.c | 68 +++++++++++++++++++++++++++++++++++++++--------
2 files changed, 60 insertions(+), 15 deletions(-)

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index ae7d4a8c728c..6197b165c8c8 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -807,11 +807,10 @@ unsigned char nfs_umode_to_dtype(umode_t mode)
* Determine the number of pages in an array of length 'len' and
* with a base offset of 'base'
*/
-static inline
-unsigned int nfs_page_array_len(unsigned int base, size_t len)
+static inline unsigned int nfs_page_array_len(unsigned int base, size_t len)
{
- return ((unsigned long)len + (unsigned long)base +
- PAGE_SIZE - 1) >> PAGE_SHIFT;
+ return ((unsigned long)len + (unsigned long)base + PAGE_SIZE - 1) >>
+ PAGE_SHIFT;
}

/*
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 315e58d73718..174462722266 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -31,6 +31,42 @@
static struct kmem_cache *nfs_page_cachep;
static const struct rpc_call_ops nfs_pgio_common_ops;

+struct nfs_page_iter_page {
+ const struct nfs_page *req;
+ size_t count;
+};
+
+static void nfs_page_iter_page_init(struct nfs_page_iter_page *i,
+ const struct nfs_page *req)
+{
+ i->req = req;
+ i->count = 0;
+}
+
+static void nfs_page_iter_page_advance(struct nfs_page_iter_page *i, size_t sz)
+{
+ const struct nfs_page *req = i->req;
+ size_t tmp = i->count + sz;
+
+ i->count = (tmp < req->wb_bytes) ? tmp : req->wb_bytes;
+}
+
+static struct page *nfs_page_iter_page_get(struct nfs_page_iter_page *i)
+{
+ const struct nfs_page *req = i->req;
+ struct page *page;
+
+ if (i->count != req->wb_bytes) {
+ size_t base = i->count + req->wb_pgbase;
+ size_t len = PAGE_SIZE - offset_in_page(base);
+
+ page = nfs_page_to_page(req, base);
+ nfs_page_iter_page_advance(i, len);
+ return page;
+ }
+ return NULL;
+}
+
static struct nfs_pgio_mirror *
nfs_pgio_get_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
{
@@ -693,13 +729,14 @@ EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
/**
* nfs_pgio_rpcsetup - Set up arguments for a pageio call
* @hdr: The pageio hdr
+ * @pgbase: base
* @count: Number of bytes to read
* @how: How to commit data (writes only)
* @cinfo: Commit information for the call (writes only)
*/
-static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
- unsigned int count,
- int how, struct nfs_commit_info *cinfo)
+static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr, unsigned int pgbase,
+ unsigned int count, int how,
+ struct nfs_commit_info *cinfo)
{
struct nfs_page *req = hdr->req;

@@ -710,7 +747,7 @@ static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
hdr->args.offset = req_offset(req);
/* pnfs_set_layoutcommit needs this */
hdr->mds_offset = hdr->args.offset;
- hdr->args.pgbase = req->wb_pgbase;
+ hdr->args.pgbase = pgbase;
hdr->args.pages = hdr->page_array.pagevec;
hdr->args.count = count;
hdr->args.context = get_nfs_open_context(nfs_req_openctx(req));
@@ -896,9 +933,10 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
struct nfs_commit_info cinfo;
struct nfs_page_array *pg_array = &hdr->page_array;
unsigned int pagecount, pageused;
+ unsigned int pg_base = offset_in_page(mirror->pg_base);
gfp_t gfp_flags = nfs_io_gfp_mask();

- pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
+ pagecount = nfs_page_array_len(pg_base, mirror->pg_count);
pg_array->npages = pagecount;

if (pagecount <= ARRAY_SIZE(pg_array->page_array))
@@ -918,19 +956,26 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
last_page = NULL;
pageused = 0;
while (!list_empty(head)) {
+ struct nfs_page_iter_page i;
+ struct page *page;
+
req = nfs_list_entry(head->next);
nfs_list_move_request(req, &hdr->pages);

if (req->wb_pgbase == 0)
last_page = NULL;

- if (!last_page || last_page != req->wb_page) {
- pageused++;
- if (pageused > pagecount)
- break;
- *pages++ = last_page = req->wb_page;
+ nfs_page_iter_page_init(&i, req);
+ while ((page = nfs_page_iter_page_get(&i)) != NULL) {
+ if (last_page != page) {
+ pageused++;
+ if (pageused > pagecount)
+ goto full;
+ *pages++ = last_page = page;
+ }
}
}
+full:
if (WARN_ON_ONCE(pageused != pagecount)) {
nfs_pgio_error(hdr);
desc->pg_error = -EINVAL;
@@ -942,7 +987,8 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
desc->pg_ioflags &= ~FLUSH_COND_STABLE;

/* Set up the argument struct */
- nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo);
+ nfs_pgio_rpcsetup(hdr, pg_base, mirror->pg_count, desc->pg_ioflags,
+ &cinfo);
desc->pg_rpc_callops = &nfs_pgio_common_ops;
return 0;
}
--
2.39.0