@@ -8,6 +8,102 @@
#include <linux/swap.h>
#include "internal.h"
+/**
+ * netfs_alloc_folioq_buffer - Allocate buffer space into a folio queue
+ * @mapping: Address space to set on the folio (or NULL).
+ * @_buffer: Pointer to the folio queue to add to (may point to a NULL; updated).
+ * @_cur_size: Current size of the buffer (updated).
+ * @size: Target size of the buffer.
+ * @gfp: The allocation constraints.
+ */
+int netfs_alloc_folioq_buffer(struct address_space *mapping,
+ struct folio_queue **_buffer,
+ size_t *_cur_size, ssize_t size, gfp_t gfp)
+{
+ struct folio_queue *tail = *_buffer, *p;
+
+ size = round_up(size, PAGE_SIZE);
+ if (*_cur_size >= size)
+ return 0;
+
+ if (tail)
+ while (tail->next)
+ tail = tail->next;
+
+ do {
+ struct folio *folio;
+ int order = 0, slot;
+
+ if (!tail || folioq_full(tail)) {
+ p = netfs_folioq_alloc(0, GFP_NOFS, netfs_trace_folioq_alloc_buffer);
+ if (!p)
+ return -ENOMEM;
+ if (tail) {
+ tail->next = p;
+ p->prev = tail;
+ } else {
+ *_buffer = p;
+ }
+ tail = p;
+ }
+
+ if (size - *_cur_size > PAGE_SIZE)
+ order = umin(ilog2(size - *_cur_size) - PAGE_SHIFT,
+ MAX_PAGECACHE_ORDER);
+
+ folio = folio_alloc(gfp, order);
+ if (!folio && order > 0)
+ folio = folio_alloc(gfp, 0);
+ if (!folio)
+ return -ENOMEM;
+
+ folio->mapping = mapping;
+ folio->index = *_cur_size / PAGE_SIZE;
+ trace_netfs_folio(folio, netfs_folio_trace_alloc_buffer);
+ slot = folioq_append_mark(tail, folio);
+ *_cur_size += folioq_folio_size(tail, slot);
+ } while (*_cur_size < size);
+
+ return 0;
+}
+EXPORT_SYMBOL(netfs_alloc_folioq_buffer);
+
+/**
+ * netfs_free_folioq_buffer - Free a folio queue.
+ * @fq: The start of the folio queue to free
+ *
+ * Free up a chain of folio_queues and, if marked, the marked folios they point
+ * to.
+ */
+void netfs_free_folioq_buffer(struct folio_queue *fq)
+{
+ struct folio_queue *next;
+ struct folio_batch fbatch;
+
+ folio_batch_init(&fbatch);
+
+ for (; fq; fq = next) {
+ for (int slot = 0; slot < folioq_count(fq); slot++) {
+ struct folio *folio = folioq_folio(fq, slot);
+
+ if (!folio ||
+ !folioq_is_marked(fq, slot))
+ continue;
+
+ trace_netfs_folio(folio, netfs_folio_trace_put);
+ if (folio_batch_add(&fbatch, folio))
+ folio_batch_release(&fbatch);
+ }
+
+ netfs_stat_d(&netfs_n_folioq);
+ next = fq->next;
+ kfree(fq);
+ }
+
+ folio_batch_release(&fbatch);
+}
+EXPORT_SYMBOL(netfs_free_folioq_buffer);
+
/*
* Reset the subrequest iterator to refer just to the region remaining to be
* read. The iterator may or may not have been advanced by socket ops or
@@ -457,6 +457,12 @@ struct folio_queue *netfs_folioq_alloc(unsigned int rreq_id, gfp_t gfp,
void netfs_folioq_free(struct folio_queue *folioq,
unsigned int trace /*enum netfs_trace_folioq*/);
+/* Buffer wrangling helpers API. */
+int netfs_alloc_folioq_buffer(struct address_space *mapping,
+ struct folio_queue **_buffer,
+ size_t *_cur_size, ssize_t size, gfp_t gfp);
+void netfs_free_folioq_buffer(struct folio_queue *fq);
+
/**
* netfs_inode - Get the netfs inode context from the inode
* @inode: The inode to query
@@ -155,6 +155,7 @@
EM(netfs_streaming_filled_page, "mod-streamw-f") \
EM(netfs_streaming_cont_filled_page, "mod-streamw-f+") \
EM(netfs_folio_trace_abandon, "abandon") \
+ EM(netfs_folio_trace_alloc_buffer, "alloc-buf") \
EM(netfs_folio_trace_cancel_copy, "cancel-copy") \
EM(netfs_folio_trace_cancel_store, "cancel-store") \
EM(netfs_folio_trace_clear, "clear") \
@@ -195,10 +196,7 @@
E_(netfs_trace_donate_to_deferred_next, "defer-next")
#define netfs_folioq_traces \
- EM(netfs_trace_folioq_alloc_append_folio, "alloc-apf") \
- EM(netfs_trace_folioq_alloc_read_prep, "alloc-r-prep") \
- EM(netfs_trace_folioq_alloc_read_prime, "alloc-r-prime") \
- EM(netfs_trace_folioq_alloc_read_sing, "alloc-r-sing") \
+ EM(netfs_trace_folioq_alloc_buffer, "alloc-buf") \
EM(netfs_trace_folioq_clear, "clear") \
EM(netfs_trace_folioq_delete, "delete") \
EM(netfs_trace_folioq_make_space, "make-space") \
Add two netfslib functions to build up or clean up a buffer in a folio_queue. The first, netfs_alloc_folioq_buffer() will add folios to a buffer, extending up at least to the given size. If it can, it will add multipage folios. The folios are optionally have the mapping set and will have the index set according to the distance from the front of the folio queue. The second function will free up a folio queue and put any folios in the queue that have the first mark set. The netfs_folio tracepoint is also altered to cope with folios that have a NULL mapping, and the folios being added/put will have trace lines emitted and will be accounted in the stats. Signed-off-by: David Howells <dhowells@redhat.com> cc: Jeff Layton <jlayton@kernel.org> cc: Marc Dionne <marc.dionne@auristor.com> cc: netfs@lists.linux.dev cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org --- fs/netfs/misc.c | 96 ++++++++++++++++++++++++++++++++++++ include/linux/netfs.h | 6 +++ include/trace/events/netfs.h | 6 +-- 3 files changed, 104 insertions(+), 4 deletions(-)