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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /fs/netfs/rolling_buffer.c
downloadlinux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz
linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
Diffstat (limited to 'fs/netfs/rolling_buffer.c')
-rw-r--r--fs/netfs/rolling_buffer.c226
1 files changed, 226 insertions, 0 deletions
diff --git a/fs/netfs/rolling_buffer.c b/fs/netfs/rolling_buffer.c
new file mode 100644
index 000000000..8c0026836
--- /dev/null
+++ b/fs/netfs/rolling_buffer.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Rolling buffer helpers
+ *
+ * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/bitops.h>
+#include <linux/mempool.h>
+#include <linux/pagemap.h>
+#include <linux/rolling_buffer.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+static atomic_t debug_ids;
+
+/**
+ * netfs_folioq_alloc - Allocate a folio_queue struct
+ * @rreq_id: Associated debugging ID for tracing purposes
+ * @gfp: Allocation constraints
+ * @trace: Trace tag to indicate the purpose of the allocation
+ *
+ * Allocate, initialise and account the folio_queue struct and log a trace line
+ * to mark the allocation.
+ */
+struct folio_queue *netfs_folioq_alloc(unsigned int rreq_id, gfp_t gfp,
+ unsigned int /*enum netfs_folioq_trace*/ trace)
+{
+ struct folio_queue *fq;
+
+ if (gfp == GFP_KERNEL)
+ fq = netfs_folioq_pool.alloc(gfp, netfs_folioq_pool.pool_data);
+ else
+ fq = mempool_alloc(&netfs_folioq_pool, gfp);
+ if (fq) {
+ netfs_stat(&netfs_n_folioq);
+ folioq_init(fq, rreq_id);
+ fq->debug_id = atomic_inc_return(&debug_ids);
+ trace_netfs_folioq(fq, trace);
+ }
+ return fq;
+}
+EXPORT_SYMBOL(netfs_folioq_alloc);
+
+/**
+ * netfs_folioq_free - Free a folio_queue struct
+ * @folioq: The object to free
+ * @trace: Trace tag to indicate which free
+ *
+ * Free and unaccount the folio_queue struct.
+ */
+void netfs_folioq_free(struct folio_queue *folioq,
+ unsigned int /*enum netfs_trace_folioq*/ trace)
+{
+ trace_netfs_folioq(folioq, trace);
+ netfs_stat_d(&netfs_n_folioq);
+ mempool_free(folioq, &netfs_folioq_pool);
+}
+EXPORT_SYMBOL(netfs_folioq_free);
+
+/*
+ * Initialise a rolling buffer. We allocate an empty folio queue struct to so
+ * that the pointers can be independently driven by the producer and the
+ * consumer.
+ */
+int rolling_buffer_init(struct rolling_buffer *roll, unsigned int rreq_id,
+ unsigned int direction, gfp_t gfp)
+{
+ struct folio_queue *fq;
+
+ fq = netfs_folioq_alloc(rreq_id, gfp, netfs_trace_folioq_rollbuf_init);
+ if (!fq)
+ return -ENOMEM;
+
+ roll->head = fq;
+ roll->tail = fq;
+ iov_iter_folio_queue(&roll->iter, direction, fq, 0, 0, 0);
+ return 0;
+}
+
+/*
+ * Add another folio_queue to a rolling buffer if there's no space left.
+ */
+int rolling_buffer_make_space(struct rolling_buffer *roll, gfp_t gfp)
+{
+ struct folio_queue *fq, *head = roll->head;
+
+ if (!folioq_full(head))
+ return 0;
+
+ fq = netfs_folioq_alloc(head->rreq_id, gfp, netfs_trace_folioq_make_space);
+ if (!fq)
+ return -ENOMEM;
+ fq->prev = head;
+
+ roll->head = fq;
+ if (folioq_full(head)) {
+ /* Make sure we don't leave the master iterator pointing to a
+ * block that might get immediately consumed.
+ */
+ if (roll->iter.folioq == head &&
+ roll->iter.folioq_slot == folioq_nr_slots(head)) {
+ roll->iter.folioq = fq;
+ roll->iter.folioq_slot = 0;
+ }
+ }
+
+ /* Make sure the initialisation is stored before the next pointer.
+ *
+ * [!] NOTE: After we set head->next, the consumer is at liberty to
+ * immediately delete the old head.
+ */
+ smp_store_release(&head->next, fq);
+ return 0;
+}
+
+/*
+ * Decant the list of folios to read into a rolling buffer.
+ */
+ssize_t rolling_buffer_load_from_ra(struct rolling_buffer *roll,
+ struct readahead_control *ractl,
+ struct folio_batch *put_batch)
+{
+ struct folio_queue *fq;
+ struct page **vec;
+ int nr, ix, to;
+ ssize_t size = 0;
+
+ if (rolling_buffer_make_space(roll, GFP_KERNEL) < 0)
+ return -ENOMEM;
+
+ fq = roll->head;
+ vec = (struct page **)fq->vec.folios;
+ nr = __readahead_batch(ractl, vec + folio_batch_count(&fq->vec),
+ folio_batch_space(&fq->vec));
+ ix = fq->vec.nr;
+ to = ix + nr;
+ fq->vec.nr = to;
+ for (; ix < to; ix++) {
+ struct folio *folio = folioq_folio(fq, ix);
+ unsigned int order = folio_order(folio);
+
+ fq->orders[ix] = order;
+ size += PAGE_SIZE << order;
+ trace_netfs_folio(folio, netfs_folio_trace_read);
+ if (!folio_batch_add(put_batch, folio))
+ folio_batch_release(put_batch);
+ }
+ WRITE_ONCE(roll->iter.count, roll->iter.count + size);
+
+ /* Store the counter after setting the slot. */
+ smp_store_release(&roll->next_head_slot, to);
+ return size;
+}
+
+/*
+ * Append a folio to the rolling buffer.
+ */
+ssize_t rolling_buffer_append(struct rolling_buffer *roll, struct folio *folio,
+ unsigned int flags, gfp_t gfp)
+{
+ ssize_t size = folio_size(folio);
+ int slot;
+
+ if (rolling_buffer_make_space(roll, gfp) < 0)
+ return -ENOMEM;
+
+ slot = folioq_append(roll->head, folio);
+ if (flags & ROLLBUF_MARK_1)
+ folioq_mark(roll->head, slot);
+ if (flags & ROLLBUF_MARK_2)
+ folioq_mark2(roll->head, slot);
+
+ WRITE_ONCE(roll->iter.count, roll->iter.count + size);
+
+ /* Store the counter after setting the slot. */
+ smp_store_release(&roll->next_head_slot, slot);
+ return size;
+}
+
+/*
+ * Delete a spent buffer from a rolling queue and return the next in line. We
+ * don't return the last buffer to keep the pointers independent, but return
+ * NULL instead.
+ */
+struct folio_queue *rolling_buffer_delete_spent(struct rolling_buffer *roll)
+{
+ struct folio_queue *spent = roll->tail, *next = READ_ONCE(spent->next);
+
+ if (!next)
+ return NULL;
+ next->prev = NULL;
+ netfs_folioq_free(spent, netfs_trace_folioq_delete);
+ roll->tail = next;
+ return next;
+}
+
+/*
+ * Clear out a rolling queue. Folios that have mark 1 set are put.
+ */
+void rolling_buffer_clear(struct rolling_buffer *roll)
+{
+ struct folio_batch fbatch;
+ struct folio_queue *p;
+
+ folio_batch_init(&fbatch);
+
+ while ((p = roll->tail)) {
+ roll->tail = p->next;
+ for (int slot = 0; slot < folioq_count(p); slot++) {
+ struct folio *folio = folioq_folio(p, slot);
+
+ if (!folio)
+ continue;
+ if (folioq_is_marked(p, slot)) {
+ trace_netfs_folio(folio, netfs_folio_trace_put);
+ if (!folio_batch_add(&fbatch, folio))
+ folio_batch_release(&fbatch);
+ }
+ }
+
+ netfs_folioq_free(p, netfs_trace_folioq_clear);
+ }
+
+ folio_batch_release(&fbatch);
+}