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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 /net/rds/page.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 'net/rds/page.c')
-rw-r--r--net/rds/page.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/net/rds/page.c b/net/rds/page.c
new file mode 100644
index 000000000..afb151eac
--- /dev/null
+++ b/net/rds/page.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2006 Oracle. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#include <linux/highmem.h>
+#include <linux/gfp.h>
+#include <linux/cpu.h>
+#include <linux/export.h>
+
+#include "rds.h"
+
+struct rds_page_remainder {
+ struct page *r_page;
+ unsigned long r_offset;
+ local_lock_t bh_lock;
+};
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct rds_page_remainder, rds_page_remainders) = {
+ .bh_lock = INIT_LOCAL_LOCK(bh_lock),
+};
+
+/**
+ * rds_page_remainder_alloc - build up regions of a message.
+ *
+ * @scat: Scatter list for message
+ * @bytes: the number of bytes needed.
+ * @gfp: the waiting behaviour of the allocation
+ *
+ * @gfp is always ored with __GFP_HIGHMEM. Callers must be prepared to
+ * kmap the pages, etc.
+ *
+ * If @bytes is at least a full page then this just returns a page from
+ * alloc_page().
+ *
+ * If @bytes is a partial page then this stores the unused region of the
+ * page in a per-cpu structure. Future partial-page allocations may be
+ * satisfied from that cached region. This lets us waste less memory on
+ * small allocations with minimal complexity. It works because the transmit
+ * path passes read-only page regions down to devices. They hold a page
+ * reference until they are done with the region.
+ */
+int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
+ gfp_t gfp)
+{
+ struct rds_page_remainder *rem;
+ struct page *page;
+ int ret;
+
+ gfp |= __GFP_HIGHMEM;
+
+ /* jump straight to allocation if we're trying for a huge page */
+ if (bytes >= PAGE_SIZE) {
+ page = alloc_page(gfp);
+ if (!page) {
+ ret = -ENOMEM;
+ } else {
+ sg_set_page(scat, page, PAGE_SIZE, 0);
+ ret = 0;
+ }
+ goto out;
+ }
+
+ local_bh_disable();
+ local_lock_nested_bh(&rds_page_remainders.bh_lock);
+ rem = this_cpu_ptr(&rds_page_remainders);
+
+ while (1) {
+ /* avoid a tiny region getting stuck by tossing it */
+ if (rem->r_page && bytes > (PAGE_SIZE - rem->r_offset)) {
+ rds_stats_inc(s_page_remainder_miss);
+ __free_page(rem->r_page);
+ rem->r_page = NULL;
+ }
+
+ /* hand out a fragment from the cached page */
+ if (rem->r_page && bytes <= (PAGE_SIZE - rem->r_offset)) {
+ sg_set_page(scat, rem->r_page, bytes, rem->r_offset);
+ get_page(sg_page(scat));
+
+ if (rem->r_offset != 0)
+ rds_stats_inc(s_page_remainder_hit);
+
+ rem->r_offset += ALIGN(bytes, 8);
+ if (rem->r_offset >= PAGE_SIZE) {
+ __free_page(rem->r_page);
+ rem->r_page = NULL;
+ }
+ ret = 0;
+ break;
+ }
+
+ /* alloc if there is nothing for us to use */
+ local_unlock_nested_bh(&rds_page_remainders.bh_lock);
+ local_bh_enable();
+
+ page = alloc_page(gfp);
+
+ local_bh_disable();
+ local_lock_nested_bh(&rds_page_remainders.bh_lock);
+ rem = this_cpu_ptr(&rds_page_remainders);
+
+ if (!page) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ /* did someone race to fill the remainder before us? */
+ if (rem->r_page) {
+ __free_page(page);
+ continue;
+ }
+
+ /* otherwise install our page and loop around to alloc */
+ rem->r_page = page;
+ rem->r_offset = 0;
+ }
+
+ local_unlock_nested_bh(&rds_page_remainders.bh_lock);
+ local_bh_enable();
+out:
+ rdsdebug("bytes %lu ret %d %p %u %u\n", bytes, ret,
+ ret ? NULL : sg_page(scat), ret ? 0 : scat->offset,
+ ret ? 0 : scat->length);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(rds_page_remainder_alloc);
+
+void rds_page_exit(void)
+{
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct rds_page_remainder *rem;
+
+ rem = &per_cpu(rds_page_remainders, cpu);
+ rdsdebug("cpu %u\n", cpu);
+
+ if (rem->r_page)
+ __free_page(rem->r_page);
+ rem->r_page = NULL;
+ }
+}