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().
  ...

1 files changed, 628 insertions, 0 deletions

diff --git a/sound/pci/emu10k1/memory.c b/sound/pci/emu10k1/memory.c
new file mode 100644
index 000000000..edb3f1763
--- /dev/null
+++ b/sound/pci/emu10k1/memory.c
@@ -0,0 +1,628 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
+ *
+ *  EMU10K1 memory page allocation (PTB area)
+ */
+
+#include <linux/pci.h>
+#include <linux/gfp.h>
+#include <linux/time.h>
+#include <linux/mutex.h>
+#include <linux/export.h>
+
+#include <sound/core.h>
+#include <sound/emu10k1.h>
+
+/* page arguments of these two macros are Emu page (4096 bytes), not like
+ * aligned pages in others
+ */
+#define __set_ptb_entry(emu,page,addr) \
+	(((__le32 *)(emu)->ptb_pages.area)[page] = \
+	 cpu_to_le32(((addr) << (emu->address_mode)) | (page)))
+#define __get_ptb_entry(emu, page) \
+	(le32_to_cpu(((__le32 *)(emu)->ptb_pages.area)[page]))
+
+#define UNIT_PAGES		(PAGE_SIZE / EMUPAGESIZE)
+#define MAX_ALIGN_PAGES0		(MAXPAGES0 / UNIT_PAGES)
+#define MAX_ALIGN_PAGES1		(MAXPAGES1 / UNIT_PAGES)
+/* get aligned page from offset address */
+#define get_aligned_page(offset)	((offset) >> PAGE_SHIFT)
+/* get offset address from aligned page */
+#define aligned_page_offset(page)	((page) << PAGE_SHIFT)
+
+#if PAGE_SIZE == EMUPAGESIZE && !IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
+/* fill PTB entrie(s) corresponding to page with addr */
+#define set_ptb_entry(emu,page,addr)	__set_ptb_entry(emu,page,addr)
+/* fill PTB entrie(s) corresponding to page with silence pointer */
+#define set_silent_ptb(emu,page)	__set_ptb_entry(emu,page,emu->silent_page.addr)
+#else
+/* fill PTB entries -- we need to fill UNIT_PAGES entries */
+static inline void set_ptb_entry(struct snd_emu10k1 *emu, int page, dma_addr_t addr)
+{
+	int i;
+	page *= UNIT_PAGES;
+	for (i = 0; i < UNIT_PAGES; i++, page++) {
+		__set_ptb_entry(emu, page, addr);
+		dev_dbg(emu->card->dev, "mapped page %d to entry %.8x\n", page,
+			(unsigned int)__get_ptb_entry(emu, page));
+		addr += EMUPAGESIZE;
+	}
+}
+static inline void set_silent_ptb(struct snd_emu10k1 *emu, int page)
+{
+	int i;
+	page *= UNIT_PAGES;
+	for (i = 0; i < UNIT_PAGES; i++, page++) {
+		/* do not increment ptr */
+		__set_ptb_entry(emu, page, emu->silent_page.addr);
+		dev_dbg(emu->card->dev, "mapped silent page %d to entry %.8x\n",
+			page, (unsigned int)__get_ptb_entry(emu, page));
+	}
+}
+#endif /* PAGE_SIZE */
+
+
+/*
+ */
+static int synth_alloc_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);
+static int synth_free_pages(struct snd_emu10k1 *hw, struct snd_emu10k1_memblk *blk);
+
+#define get_emu10k1_memblk(l,member)	list_entry(l, struct snd_emu10k1_memblk, member)
+
+
+/* initialize emu10k1 part */
+static void emu10k1_memblk_init(struct snd_emu10k1_memblk *blk)
+{
+	blk->mapped_page = -1;
+	INIT_LIST_HEAD(&blk->mapped_link);
+	INIT_LIST_HEAD(&blk->mapped_order_link);
+	blk->map_locked = 0;
+
+	blk->first_page = get_aligned_page(blk->mem.offset);
+	blk->last_page = get_aligned_page(blk->mem.offset + blk->mem.size - 1);
+	blk->pages = blk->last_page - blk->first_page + 1;
+}
+
+/*
+ * search empty region on PTB with the given size
+ *
+ * if an empty region is found, return the page and store the next mapped block
+ * in nextp
+ * if not found, return a negative error code.
+ */
+static int search_empty_map_area(struct snd_emu10k1 *emu, int npages, struct list_head **nextp)
+{
+	int page = 1, found_page = -ENOMEM;
+	int max_size = npages;
+	int size;
+	struct list_head *candidate = &emu->mapped_link_head;
+	struct list_head *pos;
+
+	list_for_each (pos, &emu->mapped_link_head) {
+		struct snd_emu10k1_memblk *blk = get_emu10k1_memblk(pos, mapped_link);
+		if (blk->mapped_page < 0)
+			continue;
+		size = blk->mapped_page - page;
+		if (size == npages) {
+			*nextp = pos;
+			return page;
+		}
+		else if (size > max_size) {
+			/* we look for the maximum empty hole */
+			max_size = size;
+			candidate = pos;
+			found_page = page;
+		}
+		page = blk->mapped_page + blk->pages;
+	}
+	size = (emu->address_mode ? MAX_ALIGN_PAGES1 : MAX_ALIGN_PAGES0) - page;
+	if (size >= max_size) {
+		*nextp = pos;
+		return page;
+	}
+	*nextp = candidate;
+	return found_page;
+}
+
+/*
+ * map a memory block onto emu10k1's PTB
+ *
+ * call with memblk_lock held
+ */
+static int map_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
+{
+	int page, pg;
+	struct list_head *next;
+
+	page = search_empty_map_area(emu, blk->pages, &next);
+	if (page < 0) /* not found */
+		return page;
+	if (page == 0) {
+		dev_err(emu->card->dev, "trying to map zero (reserved) page\n");
+		return -EINVAL;
+	}
+	/* insert this block in the proper position of mapped list */
+	list_add_tail(&blk->mapped_link, next);
+	/* append this as a newest block in order list */
+	list_add_tail(&blk->mapped_order_link, &emu->mapped_order_link_head);
+	blk->mapped_page = page;
+	/* fill PTB */
+	for (pg = blk->first_page; pg <= blk->last_page; pg++) {
+		set_ptb_entry(emu, page, emu->page_addr_table[pg]);
+		page++;
+	}
+	return 0;
+}
+
+/*
+ * unmap the block
+ * return the size of resultant empty pages
+ *
+ * call with memblk_lock held
+ */
+static int unmap_memblk(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
+{
+	int start_page, end_page, mpage, pg;
+	struct list_head *p;
+	struct snd_emu10k1_memblk *q;
+
+	/* calculate the expected size of empty region */
+	p = blk->mapped_link.prev;
+	if (p != &emu->mapped_link_head) {
+		q = get_emu10k1_memblk(p, mapped_link);
+		start_page = q->mapped_page + q->pages;
+	} else {
+		start_page = 1;
+	}
+	p = blk->mapped_link.next;
+	if (p != &emu->mapped_link_head) {
+		q = get_emu10k1_memblk(p, mapped_link);
+		end_page = q->mapped_page;
+	} else {
+		end_page = (emu->address_mode ? MAX_ALIGN_PAGES1 : MAX_ALIGN_PAGES0);
+	}
+
+	/* remove links */
+	list_del(&blk->mapped_link);
+	list_del(&blk->mapped_order_link);
+	/* clear PTB */
+	mpage = blk->mapped_page;
+	for (pg = blk->first_page; pg <= blk->last_page; pg++) {
+		set_silent_ptb(emu, mpage);
+		mpage++;
+	}
+	blk->mapped_page = -1;
+	return end_page - start_page; /* return the new empty size */
+}
+
+/*
+ * search empty pages with the given size, and create a memory block
+ *
+ * unlike synth_alloc the memory block is aligned to the page start
+ */
+static struct snd_emu10k1_memblk *
+search_empty(struct snd_emu10k1 *emu, int size)
+{
+	struct list_head *p;
+	struct snd_emu10k1_memblk *blk;
+	int page, psize;
+
+	psize = get_aligned_page(size + PAGE_SIZE -1);
+	page = 0;
+	list_for_each(p, &emu->memhdr->block) {
+		blk = get_emu10k1_memblk(p, mem.list);
+		if (page + psize <= blk->first_page)
+			goto __found_pages;
+		page = blk->last_page + 1;
+	}
+	if (page + psize > emu->max_cache_pages)
+		return NULL;
+
+__found_pages:
+	/* create a new memory block */
+	blk = (struct snd_emu10k1_memblk *)__snd_util_memblk_new(emu->memhdr, psize << PAGE_SHIFT, p->prev);
+	if (blk == NULL)
+		return NULL;
+	blk->mem.offset = aligned_page_offset(page); /* set aligned offset */
+	emu10k1_memblk_init(blk);
+	return blk;
+}
+
+
+/*
+ * check if the given pointer is valid for pages
+ */
+static int is_valid_page(struct snd_emu10k1 *emu, dma_addr_t addr)
+{
+	if (addr & ~emu->dma_mask) {
+		dev_err_ratelimited(emu->card->dev,
+			"max memory size is 0x%lx (addr = 0x%lx)!!\n",
+			emu->dma_mask, (unsigned long)addr);
+		return 0;
+	}
+	if (addr & (EMUPAGESIZE-1)) {
+		dev_err_ratelimited(emu->card->dev, "page is not aligned\n");
+		return 0;
+	}
+	return 1;
+}
+
+/*
+ * map the given memory block on PTB.
+ * if the block is already mapped, update the link order.
+ * if no empty pages are found, tries to release unused memory blocks
+ * and retry the mapping.
+ */
+int snd_emu10k1_memblk_map(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
+{
+	int err;
+	int size;
+	struct list_head *p, *nextp;
+	struct snd_emu10k1_memblk *deleted;
+	unsigned long flags;
+
+	spin_lock_irqsave(&emu->memblk_lock, flags);
+	if (blk->mapped_page >= 0) {
+		/* update order link */
+		list_move_tail(&blk->mapped_order_link,
+			       &emu->mapped_order_link_head);
+		spin_unlock_irqrestore(&emu->memblk_lock, flags);
+		return 0;
+	}
+	err = map_memblk(emu, blk);
+	if (err < 0) {
+		/* no enough page - try to unmap some blocks */
+		/* starting from the oldest block */
+		p = emu->mapped_order_link_head.next;
+		for (; p != &emu->mapped_order_link_head; p = nextp) {
+			nextp = p->next;
+			deleted = get_emu10k1_memblk(p, mapped_order_link);
+			if (deleted->map_locked)
+				continue;
+			size = unmap_memblk(emu, deleted);
+			if (size >= blk->pages) {
+				/* ok the empty region is enough large */
+				err = map_memblk(emu, blk);
+				break;
+			}
+		}
+	}
+	spin_unlock_irqrestore(&emu->memblk_lock, flags);
+	return err;
+}
+
+EXPORT_SYMBOL(snd_emu10k1_memblk_map);
+
+/*
+ * page allocation for DMA
+ */
+struct snd_util_memblk *
+snd_emu10k1_alloc_pages(struct snd_emu10k1 *emu, struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_util_memhdr *hdr;
+	struct snd_emu10k1_memblk *blk;
+	int page, err, idx;
+
+	if (snd_BUG_ON(!emu))
+		return NULL;
+	if (snd_BUG_ON(runtime->dma_bytes <= 0 ||
+		       runtime->dma_bytes >= (emu->address_mode ? MAXPAGES1 : MAXPAGES0) * EMUPAGESIZE))
+		return NULL;
+	hdr = emu->memhdr;
+	if (snd_BUG_ON(!hdr))
+		return NULL;
+
+	idx = runtime->period_size >= runtime->buffer_size ?
+					(emu->delay_pcm_irq * 2) : 0;
+	mutex_lock(&hdr->block_mutex);
+	blk = search_empty(emu, runtime->dma_bytes + idx);
+	if (blk == NULL) {
+		mutex_unlock(&hdr->block_mutex);
+		return NULL;
+	}
+	/* fill buffer addresses but pointers are not stored so that
+	 * snd_free_pci_page() is not called in synth_free()
+	 */
+	idx = 0;
+	for (page = blk->first_page; page <= blk->last_page; page++, idx++) {
+		unsigned long ofs = idx << PAGE_SHIFT;
+		dma_addr_t addr;
+		if (ofs >= runtime->dma_bytes)
+			addr = emu->silent_page.addr;
+		else
+			addr = snd_pcm_sgbuf_get_addr(substream, ofs);
+		if (! is_valid_page(emu, addr)) {
+			dev_err_ratelimited(emu->card->dev,
+				"emu: failure page = %d\n", idx);
+			mutex_unlock(&hdr->block_mutex);
+			return NULL;
+		}
+		emu->page_addr_table[page] = addr;
+		emu->page_ptr_table[page] = NULL;
+	}
+
+	/* set PTB entries */
+	blk->map_locked = 1; /* do not unmap this block! */
+	err = snd_emu10k1_memblk_map(emu, blk);
+	if (err < 0) {
+		__snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
+		mutex_unlock(&hdr->block_mutex);
+		return NULL;
+	}
+	mutex_unlock(&hdr->block_mutex);
+	return (struct snd_util_memblk *)blk;
+}
+
+
+/*
+ * release DMA buffer from page table
+ */
+int snd_emu10k1_free_pages(struct snd_emu10k1 *emu, struct snd_util_memblk *blk)
+{
+	if (snd_BUG_ON(!emu || !blk))
+		return -EINVAL;
+	return snd_emu10k1_synth_free(emu, blk);
+}
+
+/*
+ * allocate DMA pages, widening the allocation if necessary
+ *
+ * See the comment above snd_emu10k1_detect_iommu() in emu10k1_main.c why
+ * this might be needed.
+ *
+ * If you modify this function check whether __synth_free_pages() also needs
+ * changes.
+ */
+int snd_emu10k1_alloc_pages_maybe_wider(struct snd_emu10k1 *emu, size_t size,
+					struct snd_dma_buffer *dmab)
+{
+	if (emu->iommu_workaround) {
+		size_t npages = DIV_ROUND_UP(size, PAGE_SIZE);
+		size_t size_real = npages * PAGE_SIZE;
+
+		/*
+		 * The device has been observed to accesses up to 256 extra
+		 * bytes, but use 1k to be safe.
+		 */
+		if (size_real < size + 1024)
+			size += PAGE_SIZE;
+	}
+
+	return snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV,
+				   &emu->pci->dev, size, dmab);
+}
+
+/*
+ * memory allocation using multiple pages (for synth)
+ * Unlike the DMA allocation above, non-contiguous pages are assined.
+ */
+
+/*
+ * allocate a synth sample area
+ */
+struct snd_util_memblk *
+snd_emu10k1_synth_alloc(struct snd_emu10k1 *hw, unsigned int size)
+{
+	struct snd_emu10k1_memblk *blk;
+	struct snd_util_memhdr *hdr = hw->memhdr; 
+
+	mutex_lock(&hdr->block_mutex);
+	blk = (struct snd_emu10k1_memblk *)__snd_util_mem_alloc(hdr, size);
+	if (blk == NULL) {
+		mutex_unlock(&hdr->block_mutex);
+		return NULL;
+	}
+	if (synth_alloc_pages(hw, blk)) {
+		__snd_util_mem_free(hdr, (struct snd_util_memblk *)blk);
+		mutex_unlock(&hdr->block_mutex);
+		return NULL;
+	}
+	snd_emu10k1_memblk_map(hw, blk);
+	mutex_unlock(&hdr->block_mutex);
+	return (struct snd_util_memblk *)blk;
+}
+
+EXPORT_SYMBOL(snd_emu10k1_synth_alloc);
+
+/*
+ * free a synth sample area
+ */
+int
+snd_emu10k1_synth_free(struct snd_emu10k1 *emu, struct snd_util_memblk *memblk)
+{
+	struct snd_util_memhdr *hdr = emu->memhdr; 
+	struct snd_emu10k1_memblk *blk = (struct snd_emu10k1_memblk *)memblk;
+	unsigned long flags;
+
+	mutex_lock(&hdr->block_mutex);
+	spin_lock_irqsave(&emu->memblk_lock, flags);
+	if (blk->mapped_page >= 0)
+		unmap_memblk(emu, blk);
+	spin_unlock_irqrestore(&emu->memblk_lock, flags);
+	synth_free_pages(emu, blk);
+	 __snd_util_mem_free(hdr, memblk);
+	mutex_unlock(&hdr->block_mutex);
+	return 0;
+}
+
+EXPORT_SYMBOL(snd_emu10k1_synth_free);
+
+/* check new allocation range */
+static void get_single_page_range(struct snd_util_memhdr *hdr,
+				  struct snd_emu10k1_memblk *blk,
+				  int *first_page_ret, int *last_page_ret)
+{
+	struct list_head *p;
+	struct snd_emu10k1_memblk *q;
+	int first_page, last_page;
+	first_page = blk->first_page;
+	p = blk->mem.list.prev;
+	if (p != &hdr->block) {
+		q = get_emu10k1_memblk(p, mem.list);
+		if (q->last_page == first_page)
+			first_page++;  /* first page was already allocated */
+	}
+	last_page = blk->last_page;
+	p = blk->mem.list.next;
+	if (p != &hdr->block) {
+		q = get_emu10k1_memblk(p, mem.list);
+		if (q->first_page == last_page)
+			last_page--; /* last page was already allocated */
+	}
+	*first_page_ret = first_page;
+	*last_page_ret = last_page;
+}
+
+/* release allocated pages */
+static void __synth_free_pages(struct snd_emu10k1 *emu, int first_page,
+			       int last_page)
+{
+	struct snd_dma_buffer dmab;
+	int page;
+
+	dmab.dev.type = SNDRV_DMA_TYPE_DEV;
+	dmab.dev.dev = &emu->pci->dev;
+
+	for (page = first_page; page <= last_page; page++) {
+		if (emu->page_ptr_table[page] == NULL)
+			continue;
+		dmab.area = emu->page_ptr_table[page];
+		dmab.addr = emu->page_addr_table[page];
+
+		/*
+		 * please keep me in sync with logic in
+		 * snd_emu10k1_alloc_pages_maybe_wider()
+		 */
+		dmab.bytes = PAGE_SIZE;
+		if (emu->iommu_workaround)
+			dmab.bytes *= 2;
+
+		snd_dma_free_pages(&dmab);
+		emu->page_addr_table[page] = 0;
+		emu->page_ptr_table[page] = NULL;
+	}
+}
+
+/*
+ * allocate kernel pages
+ */
+static int synth_alloc_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
+{
+	int page, first_page, last_page;
+	struct snd_dma_buffer dmab;
+
+	emu10k1_memblk_init(blk);
+	get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
+	/* allocate kernel pages */
+	for (page = first_page; page <= last_page; page++) {
+		if (snd_emu10k1_alloc_pages_maybe_wider(emu, PAGE_SIZE,
+							&dmab) < 0)
+			goto __fail;
+		if (!is_valid_page(emu, dmab.addr)) {
+			snd_dma_free_pages(&dmab);
+			goto __fail;
+		}
+		emu->page_addr_table[page] = dmab.addr;
+		emu->page_ptr_table[page] = dmab.area;
+	}
+	return 0;
+
+__fail:
+	/* release allocated pages */
+	last_page = page - 1;
+	__synth_free_pages(emu, first_page, last_page);
+
+	return -ENOMEM;
+}
+
+/*
+ * free pages
+ */
+static int synth_free_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
+{
+	int first_page, last_page;
+
+	get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
+	__synth_free_pages(emu, first_page, last_page);
+	return 0;
+}
+
+/* calculate buffer pointer from offset address */
+static inline void *offset_ptr(struct snd_emu10k1 *emu, int page, int offset)
+{
+	char *ptr;
+	if (snd_BUG_ON(page < 0 || page >= emu->max_cache_pages))
+		return NULL;
+	ptr = emu->page_ptr_table[page];
+	if (! ptr) {
+		dev_err(emu->card->dev,
+			"access to NULL ptr: page = %d\n", page);
+		return NULL;
+	}
+	ptr += offset & (PAGE_SIZE - 1);
+	return (void*)ptr;
+}
+
+/*
+ * bzero(blk + offset, size)
+ */
+int snd_emu10k1_synth_bzero(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
+			    int offset, int size)
+{
+	int page, nextofs, end_offset, temp, temp1;
+	void *ptr;
+	struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;
+
+	offset += blk->offset & (PAGE_SIZE - 1);
+	end_offset = offset + size;
+	page = get_aligned_page(offset);
+	do {
+		nextofs = aligned_page_offset(page + 1);
+		temp = nextofs - offset;
+		temp1 = end_offset - offset;
+		if (temp1 < temp)
+			temp = temp1;
+		ptr = offset_ptr(emu, page + p->first_page, offset);
+		if (ptr)
+			memset(ptr, 0, temp);
+		offset = nextofs;
+		page++;
+	} while (offset < end_offset);
+	return 0;
+}
+
+EXPORT_SYMBOL(snd_emu10k1_synth_bzero);
+
+/*
+ * copy_from_user(blk + offset, data, size)
+ */
+int snd_emu10k1_synth_copy_from_user(struct snd_emu10k1 *emu, struct snd_util_memblk *blk,
+				     int offset, const char __user *data, int size)
+{
+	int page, nextofs, end_offset, temp, temp1;
+	void *ptr;
+	struct snd_emu10k1_memblk *p = (struct snd_emu10k1_memblk *)blk;
+
+	offset += blk->offset & (PAGE_SIZE - 1);
+	end_offset = offset + size;
+	page = get_aligned_page(offset);
+	do {
+		nextofs = aligned_page_offset(page + 1);
+		temp = nextofs - offset;
+		temp1 = end_offset - offset;
+		if (temp1 < temp)
+			temp = temp1;
+		ptr = offset_ptr(emu, page + p->first_page, offset);
+		if (ptr && copy_from_user(ptr, data, temp))
+			return -EFAULT;
+		offset = nextofs;
+		data += temp;
+		page++;
+	} while (offset < end_offset);
+	return 0;
+}
+
+EXPORT_SYMBOL(snd_emu10k1_synth_copy_from_user);