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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /drivers/media/dvb-core/dvb_ringbuffer.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
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Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'drivers/media/dvb-core/dvb_ringbuffer.c')
-rw-r--r--drivers/media/dvb-core/dvb_ringbuffer.c371
1 files changed, 371 insertions, 0 deletions
diff --git a/drivers/media/dvb-core/dvb_ringbuffer.c b/drivers/media/dvb-core/dvb_ringbuffer.c
new file mode 100644
index 000000000..7d4558de8
--- /dev/null
+++ b/drivers/media/dvb-core/dvb_ringbuffer.c
@@ -0,0 +1,371 @@
+/*
+ *
+ * dvb_ringbuffer.c: ring buffer implementation for the dvb driver
+ *
+ * Copyright (C) 2003 Oliver Endriss
+ * Copyright (C) 2004 Andrew de Quincey
+ *
+ * based on code originally found in av7110.c & dvb_ci.c:
+ * Copyright (C) 1999-2003 Ralph Metzler
+ * & Marcus Metzler for convergence integrated media GmbH
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ */
+
+
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+
+#include <media/dvb_ringbuffer.h>
+
+#define PKT_READY 0
+#define PKT_DISPOSED 1
+
+
+void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
+{
+ rbuf->pread=rbuf->pwrite=0;
+ rbuf->data=data;
+ rbuf->size=len;
+ rbuf->error=0;
+
+ init_waitqueue_head(&rbuf->queue);
+
+ spin_lock_init(&(rbuf->lock));
+}
+
+
+
+int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
+{
+ /* smp_load_acquire() to load write pointer on reader side
+ * this pairs with smp_store_release() in dvb_ringbuffer_write(),
+ * dvb_ringbuffer_write_user(), or dvb_ringbuffer_reset()
+ *
+ * for memory barriers also see Documentation/core-api/circular-buffers.rst
+ */
+ return (rbuf->pread == smp_load_acquire(&rbuf->pwrite));
+}
+
+
+
+ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
+{
+ ssize_t free;
+
+ /* READ_ONCE() to load read pointer on writer side
+ * this pairs with smp_store_release() in dvb_ringbuffer_read(),
+ * dvb_ringbuffer_read_user(), dvb_ringbuffer_flush(),
+ * or dvb_ringbuffer_reset()
+ */
+ free = READ_ONCE(rbuf->pread) - rbuf->pwrite;
+ if (free <= 0)
+ free += rbuf->size;
+ return free-1;
+}
+
+
+
+ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
+{
+ ssize_t avail;
+
+ /* smp_load_acquire() to load write pointer on reader side
+ * this pairs with smp_store_release() in dvb_ringbuffer_write(),
+ * dvb_ringbuffer_write_user(), or dvb_ringbuffer_reset()
+ */
+ avail = smp_load_acquire(&rbuf->pwrite) - rbuf->pread;
+ if (avail < 0)
+ avail += rbuf->size;
+ return avail;
+}
+
+
+
+void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
+{
+ /* dvb_ringbuffer_flush() counts as read operation
+ * smp_load_acquire() to load write pointer
+ * smp_store_release() to update read pointer, this ensures that the
+ * correct pointer is visible for subsequent dvb_ringbuffer_free()
+ * calls on other cpu cores
+ */
+ smp_store_release(&rbuf->pread, smp_load_acquire(&rbuf->pwrite));
+ rbuf->error = 0;
+}
+EXPORT_SYMBOL(dvb_ringbuffer_flush);
+
+void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf)
+{
+ /* dvb_ringbuffer_reset() counts as read and write operation
+ * smp_store_release() to update read pointer
+ */
+ smp_store_release(&rbuf->pread, 0);
+ /* smp_store_release() to update write pointer */
+ smp_store_release(&rbuf->pwrite, 0);
+ rbuf->error = 0;
+}
+
+void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&rbuf->lock, flags);
+ dvb_ringbuffer_flush(rbuf);
+ spin_unlock_irqrestore(&rbuf->lock, flags);
+
+ wake_up(&rbuf->queue);
+}
+
+ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len)
+{
+ size_t todo = len;
+ size_t split;
+
+ split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
+ if (split > 0) {
+ if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
+ return -EFAULT;
+ buf += split;
+ todo -= split;
+ /* smp_store_release() for read pointer update to ensure
+ * that buf is not overwritten until read is complete,
+ * this pairs with READ_ONCE() in dvb_ringbuffer_free()
+ */
+ smp_store_release(&rbuf->pread, 0);
+ }
+ if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
+ return -EFAULT;
+
+ /* smp_store_release() to update read pointer, see above */
+ smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size);
+
+ return len;
+}
+
+void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len)
+{
+ size_t todo = len;
+ size_t split;
+
+ split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
+ if (split > 0) {
+ memcpy(buf, rbuf->data+rbuf->pread, split);
+ buf += split;
+ todo -= split;
+ /* smp_store_release() for read pointer update to ensure
+ * that buf is not overwritten until read is complete,
+ * this pairs with READ_ONCE() in dvb_ringbuffer_free()
+ */
+ smp_store_release(&rbuf->pread, 0);
+ }
+ memcpy(buf, rbuf->data+rbuf->pread, todo);
+
+ /* smp_store_release() to update read pointer, see above */
+ smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size);
+}
+
+
+ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
+{
+ size_t todo = len;
+ size_t split;
+
+ split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
+
+ if (split > 0) {
+ memcpy(rbuf->data+rbuf->pwrite, buf, split);
+ buf += split;
+ todo -= split;
+ /* smp_store_release() for write pointer update to ensure that
+ * written data is visible on other cpu cores before the pointer
+ * update, this pairs with smp_load_acquire() in
+ * dvb_ringbuffer_empty() or dvb_ringbuffer_avail()
+ */
+ smp_store_release(&rbuf->pwrite, 0);
+ }
+ memcpy(rbuf->data+rbuf->pwrite, buf, todo);
+ /* smp_store_release() for write pointer update, see above */
+ smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size);
+
+ return len;
+}
+
+ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
+ const u8 __user *buf, size_t len)
+{
+ int status;
+ size_t todo = len;
+ size_t split;
+
+ split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
+
+ if (split > 0) {
+ status = copy_from_user(rbuf->data+rbuf->pwrite, buf, split);
+ if (status)
+ return len - todo;
+ buf += split;
+ todo -= split;
+ /* smp_store_release() for write pointer update to ensure that
+ * written data is visible on other cpu cores before the pointer
+ * update, this pairs with smp_load_acquire() in
+ * dvb_ringbuffer_empty() or dvb_ringbuffer_avail()
+ */
+ smp_store_release(&rbuf->pwrite, 0);
+ }
+ status = copy_from_user(rbuf->data+rbuf->pwrite, buf, todo);
+ if (status)
+ return len - todo;
+ /* smp_store_release() for write pointer update, see above */
+ smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size);
+
+ return len;
+}
+
+ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
+{
+ int status;
+ ssize_t oldpwrite = rbuf->pwrite;
+
+ DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
+ DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
+ DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
+ status = dvb_ringbuffer_write(rbuf, buf, len);
+
+ if (status < 0) rbuf->pwrite = oldpwrite;
+ return status;
+}
+
+ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx,
+ int offset, u8 __user *buf, size_t len)
+{
+ size_t todo;
+ size_t split;
+ size_t pktlen;
+
+ pktlen = rbuf->data[idx] << 8;
+ pktlen |= rbuf->data[(idx + 1) % rbuf->size];
+ if (offset > pktlen) return -EINVAL;
+ if ((offset + len) > pktlen) len = pktlen - offset;
+
+ idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
+ todo = len;
+ split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
+ if (split > 0) {
+ if (copy_to_user(buf, rbuf->data+idx, split))
+ return -EFAULT;
+ buf += split;
+ todo -= split;
+ idx = 0;
+ }
+ if (copy_to_user(buf, rbuf->data+idx, todo))
+ return -EFAULT;
+
+ return len;
+}
+
+ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
+ int offset, u8* buf, size_t len)
+{
+ size_t todo;
+ size_t split;
+ size_t pktlen;
+
+ pktlen = rbuf->data[idx] << 8;
+ pktlen |= rbuf->data[(idx + 1) % rbuf->size];
+ if (offset > pktlen) return -EINVAL;
+ if ((offset + len) > pktlen) len = pktlen - offset;
+
+ idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
+ todo = len;
+ split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
+ if (split > 0) {
+ memcpy(buf, rbuf->data+idx, split);
+ buf += split;
+ todo -= split;
+ idx = 0;
+ }
+ memcpy(buf, rbuf->data+idx, todo);
+ return len;
+}
+
+void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
+{
+ size_t pktlen;
+
+ rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;
+
+ // clean up disposed packets
+ while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
+ if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
+ pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
+ pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
+ DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
+ } else {
+ // first packet is not disposed, so we stop cleaning now
+ break;
+ }
+ }
+}
+
+ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
+{
+ int consumed;
+ int curpktlen;
+ int curpktstatus;
+
+ if (idx == -1) {
+ idx = rbuf->pread;
+ } else {
+ curpktlen = rbuf->data[idx] << 8;
+ curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
+ idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
+ }
+
+ consumed = (idx - rbuf->pread);
+ if (consumed < 0)
+ consumed += rbuf->size;
+
+ while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {
+
+ curpktlen = rbuf->data[idx] << 8;
+ curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
+ curpktstatus = rbuf->data[(idx + 2) % rbuf->size];
+
+ if (curpktstatus == PKT_READY) {
+ *pktlen = curpktlen;
+ return idx;
+ }
+
+ consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
+ idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
+ }
+
+ // no packets available
+ return -1;
+}
+
+
+
+EXPORT_SYMBOL(dvb_ringbuffer_init);
+EXPORT_SYMBOL(dvb_ringbuffer_empty);
+EXPORT_SYMBOL(dvb_ringbuffer_free);
+EXPORT_SYMBOL(dvb_ringbuffer_avail);
+EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
+EXPORT_SYMBOL(dvb_ringbuffer_read_user);
+EXPORT_SYMBOL(dvb_ringbuffer_read);
+EXPORT_SYMBOL(dvb_ringbuffer_write);
+EXPORT_SYMBOL(dvb_ringbuffer_write_user);