[rds-devel] [PATCH 09/21] RDS: Message parsing
Andy Grover
andy.grover at oracle.com
Mon Jan 26 18:17:46 PST 2009
Parsing of newly-received RDS message headers (including ext.
headers) and copy-to/from-user routines.
page.c implements a per-cpu page remainder cache, to reduce the
number of allocations needed for small datagrams.
Signed-off-by: Andy Grover <andy.grover at oracle.com>
---
drivers/infiniband/ulp/rds/message.c | 414 ++++++++++++++++++++++++++++++++++
drivers/infiniband/ulp/rds/page.c | 222 ++++++++++++++++++
2 files changed, 636 insertions(+), 0 deletions(-)
create mode 100644 drivers/infiniband/ulp/rds/message.c
create mode 100644 drivers/infiniband/ulp/rds/page.c
diff --git a/drivers/infiniband/ulp/rds/message.c b/drivers/infiniband/ulp/rds/message.c
new file mode 100644
index 0000000..5cad4d5
--- /dev/null
+++ b/drivers/infiniband/ulp/rds/message.c
@@ -0,0 +1,414 @@
+/*
+ * 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/kernel.h>
+
+#include "rds.h"
+#include "rdma.h"
+
+static DECLARE_WAIT_QUEUE_HEAD(rds_message_flush_waitq);
+
+static unsigned int rds_exthdr_size[__RDS_EXTHDR_MAX] = {
+[RDS_EXTHDR_NONE] = 0,
+[RDS_EXTHDR_VERSION] = sizeof(struct rds_ext_header_version),
+[RDS_EXTHDR_RDMA] = sizeof(struct rds_ext_header_rdma),
+[RDS_EXTHDR_RDMA_DEST] = sizeof(struct rds_ext_header_rdma_dest),
+};
+
+
+void rds_message_addref(struct rds_message *rm)
+{
+ rdsdebug("addref rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
+ atomic_inc(&rm->m_refcount);
+}
+EXPORT_SYMBOL_GPL(rds_message_addref);
+
+/*
+ * This relies on dma_map_sg() not touching sg[].page during merging.
+ */
+static void rds_message_purge(struct rds_message *rm)
+{
+ unsigned long i;
+
+ if (unlikely(test_bit(RDS_MSG_PAGEVEC, &rm->m_flags)))
+ return;
+
+ for (i = 0; i < rm->m_nents; i++) {
+ rdsdebug("putting data page %p\n", (void *)sg_page(&rm->m_sg[i]));
+ /* XXX will have to put_page for page refs */
+ __free_page(sg_page(&rm->m_sg[i]));
+ }
+ rm->m_nents = 0;
+
+ if (rm->m_rdma_op)
+ rds_rdma_free_op(rm->m_rdma_op);
+ if (rm->m_rdma_mr)
+ rds_mr_put(rm->m_rdma_mr);
+}
+
+void rds_message_inc_purge(struct rds_incoming *inc)
+{
+ struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
+ rds_message_purge(rm);
+}
+
+void rds_message_put(struct rds_message *rm)
+{
+ rdsdebug("put rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
+
+ if (atomic_dec_and_test(&rm->m_refcount)) {
+ BUG_ON(!list_empty(&rm->m_sock_item));
+ BUG_ON(!list_empty(&rm->m_conn_item));
+ rds_message_purge(rm);
+
+ kfree(rm);
+ }
+}
+EXPORT_SYMBOL_GPL(rds_message_put);
+
+void rds_message_inc_free(struct rds_incoming *inc)
+{
+ struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
+ rds_message_put(rm);
+}
+
+void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
+ __be16 dport, u64 seq)
+{
+ hdr->h_flags = 0;
+ hdr->h_sport = sport;
+ hdr->h_dport = dport;
+ hdr->h_sequence = cpu_to_be64(seq);
+ hdr->h_exthdr[0] = RDS_EXTHDR_NONE;
+}
+EXPORT_SYMBOL_GPL(rds_message_populate_header);
+
+int rds_message_add_extension(struct rds_header *hdr,
+ unsigned int type, const void *data, unsigned int len)
+{
+ unsigned int ext_len = sizeof(u8) + len;
+ unsigned char *dst;
+
+ /* For now, refuse to add more than one extension header */
+ if (hdr->h_exthdr[0] != RDS_EXTHDR_NONE)
+ return 0;
+
+ if (type >= __RDS_EXTHDR_MAX
+ || len != rds_exthdr_size[type])
+ return 0;
+
+ if (ext_len >= RDS_HEADER_EXT_SPACE)
+ return 0;
+ dst = hdr->h_exthdr;
+
+ *dst++ = type;
+ memcpy(dst, data, len);
+
+ dst[len] = RDS_EXTHDR_NONE;
+ return 1;
+}
+EXPORT_SYMBOL_GPL(rds_message_add_extension);
+
+/*
+ * If a message has extension headers, retrieve them here.
+ * Call like this:
+ *
+ * unsigned int pos = 0;
+ *
+ * while (1) {
+ * buflen = sizeof(buffer);
+ * type = rds_message_next_extension(hdr, &pos, buffer, &buflen);
+ * if (type == RDS_EXTHDR_NONE)
+ * break;
+ * ...
+ * }
+ */
+int rds_message_next_extension(struct rds_header *hdr,
+ unsigned int *pos, void *buf, unsigned int *buflen)
+{
+ unsigned int offset, ext_type, ext_len;
+ u8 *src = hdr->h_exthdr;
+
+ offset = *pos;
+ if (offset >= RDS_HEADER_EXT_SPACE)
+ goto none;
+
+ /* Get the extension type and length. For now, the
+ * length is implied by the extension type. */
+ ext_type = src[offset++];
+
+ if (ext_type == RDS_EXTHDR_NONE || ext_type >= __RDS_EXTHDR_MAX)
+ goto none;
+ ext_len = rds_exthdr_size[ext_type];
+ if (offset + ext_len > RDS_HEADER_EXT_SPACE)
+ goto none;
+
+ *pos = offset + ext_len;
+ if (ext_len < *buflen)
+ *buflen = ext_len;
+ memcpy(buf, src + offset, *buflen);
+ return ext_type;
+
+none:
+ *pos = RDS_HEADER_EXT_SPACE;
+ *buflen = 0;
+ return RDS_EXTHDR_NONE;
+}
+
+int rds_message_add_version_extension(struct rds_header *hdr, unsigned int version)
+{
+ struct rds_ext_header_version ext_hdr;
+
+ ext_hdr.h_version = cpu_to_be32(version);
+ return rds_message_add_extension(hdr, RDS_EXTHDR_VERSION, &ext_hdr, sizeof(ext_hdr));
+}
+
+int rds_message_get_version_extension(struct rds_header *hdr, unsigned int *version)
+{
+ struct rds_ext_header_version ext_hdr;
+ unsigned int pos = 0, len = sizeof(ext_hdr);
+
+ /* We assume the version extension is the only one present */
+ if (rds_message_next_extension(hdr, &pos, &ext_hdr, &len) != RDS_EXTHDR_VERSION)
+ return 0;
+ *version = be32_to_cpu(ext_hdr.h_version);
+ return 1;
+}
+
+int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
+{
+ struct rds_ext_header_rdma_dest ext_hdr;
+
+ ext_hdr.h_rdma_rkey = cpu_to_be32(r_key);
+ ext_hdr.h_rdma_offset = cpu_to_be32(offset);
+ return rds_message_add_extension(hdr, RDS_EXTHDR_RDMA_DEST, &ext_hdr, sizeof(ext_hdr));
+}
+EXPORT_SYMBOL_GPL(rds_message_add_rdma_dest_extension);
+
+struct rds_message *rds_message_alloc(unsigned int nents, gfp_t gfp)
+{
+ struct rds_message *rm;
+
+ rm = kzalloc(sizeof(struct rds_message) +
+ (nents * sizeof(struct scatterlist)), gfp);
+ if (!rm)
+ goto out;
+
+#ifdef CONFIG_DEBUG_SG
+{
+ unsigned int i;
+
+ for (i=0; i < nents; i++)
+ rm->m_sg[i].sg_magic = SG_MAGIC;
+}
+#endif
+ atomic_set(&rm->m_refcount, 1);
+ INIT_LIST_HEAD(&rm->m_sock_item);
+ INIT_LIST_HEAD(&rm->m_conn_item);
+ spin_lock_init(&rm->m_rs_lock);
+
+out:
+ return rm;
+}
+
+struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
+{
+ struct rds_message *rm;
+ unsigned int i;
+
+ rm = rds_message_alloc(ceil(total_len, PAGE_SIZE), GFP_KERNEL);
+ if (rm == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
+ rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
+ rm->m_nents = ceil(total_len, PAGE_SIZE);
+
+ for (i = 0; i < rm->m_nents; ++i) {
+ sg_set_page(&rm->m_sg[i],
+ virt_to_page(page_addrs[i]),
+ PAGE_SIZE, 0);
+ }
+
+ return rm;
+}
+
+struct rds_message *rds_message_copy_from_user(struct iovec *first_iov,
+ size_t total_len)
+{
+ unsigned long to_copy;
+ unsigned long iov_off;
+ unsigned long sg_off;
+ struct rds_message *rm;
+ struct iovec *iov;
+ struct scatterlist *sg;
+ int ret;
+
+ rm = rds_message_alloc(ceil(total_len, PAGE_SIZE), GFP_KERNEL);
+ if (rm == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
+
+ /*
+ * now allocate and copy in the data payload.
+ */
+ sg = rm->m_sg;
+ iov = first_iov;
+ iov_off = 0;
+ sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */
+
+ while (total_len) {
+ if (sg_page(sg) == NULL) {
+ ret = rds_page_remainder_alloc(sg, total_len,
+ GFP_HIGHUSER);
+ if (ret)
+ goto out;
+ rm->m_nents++;
+ sg_off = 0;
+ }
+
+ while (iov_off == iov->iov_len) {
+ iov_off = 0;
+ iov++;
+ }
+
+ to_copy = min(iov->iov_len - iov_off, sg->length - sg_off);
+ to_copy = min_t(size_t, to_copy, total_len);
+
+ rdsdebug("copying %lu bytes from user iov [%p, %zu] + %lu to "
+ "sg [%p, %u, %u] + %lu\n",
+ to_copy, iov->iov_base, iov->iov_len, iov_off,
+ (void *)sg_page(sg), sg->offset, sg->length, sg_off);
+
+ ret = rds_page_copy_from_user(sg_page(sg), sg->offset + sg_off,
+ iov->iov_base + iov_off,
+ to_copy);
+ if (ret)
+ goto out;
+
+ iov_off += to_copy;
+ total_len -= to_copy;
+ sg_off += to_copy;
+
+ if (sg_off == sg->length)
+ sg++;
+ }
+
+ ret = 0;
+out:
+ if (ret) {
+ if (rm)
+ rds_message_put(rm);
+ rm = ERR_PTR(ret);
+ }
+ return rm;
+}
+
+int rds_message_inc_copy_to_user(struct rds_incoming *inc,
+ struct iovec *first_iov, size_t size)
+{
+ struct rds_message *rm;
+ struct iovec *iov;
+ struct scatterlist *sg;
+ unsigned long to_copy;
+ unsigned long iov_off;
+ unsigned long vec_off;
+ int copied;
+ int ret;
+ u32 len;
+
+ rm = container_of(inc, struct rds_message, m_inc);
+ len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
+
+ iov = first_iov;
+ iov_off = 0;
+ sg = rm->m_sg;
+ vec_off = 0;
+ copied = 0;
+
+ while (copied < size && copied < len) {
+ while (iov_off == iov->iov_len) {
+ iov_off = 0;
+ iov++;
+ }
+
+ to_copy = min(iov->iov_len - iov_off, sg->length - vec_off);
+ to_copy = min_t(size_t, to_copy, size - copied);
+ to_copy = min_t(unsigned long, to_copy, len - copied);
+
+ rdsdebug("copying %lu bytes to user iov [%p, %zu] + %lu to "
+ "sg [%p, %u, %u] + %lu\n",
+ to_copy, iov->iov_base, iov->iov_len, iov_off,
+ sg_page(sg), sg->offset, sg->length, vec_off);
+
+ ret = rds_page_copy_to_user(sg_page(sg), sg->offset + vec_off,
+ iov->iov_base + iov_off,
+ to_copy);
+ if (ret) {
+ copied = ret;
+ break;
+ }
+
+ iov_off += to_copy;
+ vec_off += to_copy;
+ copied += to_copy;
+
+ if (vec_off == sg->length) {
+ vec_off = 0;
+ sg++;
+ }
+ }
+
+ return copied;
+}
+
+/*
+ * If the message is still on the send queue, wait until the transport
+ * is done with it. This is particularly important for RDMA operations.
+ */
+void rds_message_wait(struct rds_message *rm)
+{
+ wait_event(rds_message_flush_waitq,
+ !test_bit(RDS_MSG_MAPPED, &rm->m_flags));
+}
+
+void rds_message_unmapped(struct rds_message *rm)
+{
+ clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
+ if (waitqueue_active(&rds_message_flush_waitq))
+ wake_up(&rds_message_flush_waitq);
+}
+EXPORT_SYMBOL_GPL(rds_message_unmapped);
+
diff --git a/drivers/infiniband/ulp/rds/page.c b/drivers/infiniband/ulp/rds/page.c
new file mode 100644
index 0000000..55c21ef
--- /dev/null
+++ b/drivers/infiniband/ulp/rds/page.c
@@ -0,0 +1,222 @@
+/*
+ * 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 "rds.h"
+
+struct rds_page_remainder {
+ struct page *r_page;
+ unsigned long r_offset;
+};
+
+DEFINE_PER_CPU(struct rds_page_remainder, rds_page_remainders) ____cacheline_aligned;
+
+/*
+ * returns 0 on success or -errno on failure.
+ *
+ * We don't have to worry about flush_dcache_page() as this only works
+ * with private pages. If, say, we were to do directed receive to pinned
+ * user pages we'd have to worry more about cache coherence. (Though
+ * the flush_dcache_page() in get_user_pages() would probably be enough).
+ */
+int rds_page_copy_user(struct page *page, unsigned long offset,
+ void __user *ptr, unsigned long bytes,
+ int to_user)
+{
+ unsigned long ret;
+ void *addr;
+
+ if (to_user)
+ rds_stats_add(s_copy_to_user, bytes);
+ else
+ rds_stats_add(s_copy_from_user, bytes);
+
+ addr = kmap_atomic(page, KM_USER0);
+ if (to_user)
+ ret = __copy_to_user_inatomic(ptr, addr + offset, bytes);
+ else
+ ret = __copy_from_user_inatomic(addr + offset, ptr, bytes);
+ kunmap_atomic(addr, KM_USER0);
+
+ if (ret) {
+ addr = kmap(page);
+ if (to_user)
+ ret = copy_to_user(ptr, addr + offset, bytes);
+ else
+ ret = copy_from_user(addr + offset, ptr, bytes);
+ kunmap(page);
+ if (ret)
+ return -EFAULT;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(rds_page_copy_user);
+
+/*
+ * Message allocation uses this to build up regions of a 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;
+ unsigned long flags;
+ 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 == NULL) {
+ ret = -ENOMEM;
+ } else {
+ sg_set_page(scat, page, PAGE_SIZE, 0);
+ ret = 0;
+ }
+ goto out;
+ }
+
+ rem = &per_cpu(rds_page_remainders, get_cpu());
+ local_irq_save(flags);
+
+ 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 += bytes;
+ 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_irq_restore(flags);
+ put_cpu();
+
+ page = alloc_page(gfp);
+
+ rem = &per_cpu(rds_page_remainders, get_cpu());
+ local_irq_save(flags);
+
+ if (page == NULL) {
+ 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_irq_restore(flags);
+ put_cpu();
+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;
+}
+
+static int rds_page_remainder_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ struct rds_page_remainder *rem;
+ long cpu = (long)hcpu;
+
+ rem = &per_cpu(rds_page_remainders, cpu);
+
+ rdsdebug("cpu %ld action 0x%lx\n", cpu, action);
+
+ switch (action) {
+ case CPU_DEAD:
+ if (rem->r_page)
+ __free_page(rem->r_page);
+ rem->r_page = NULL;
+ break;
+ }
+
+ return 0;
+}
+
+static struct notifier_block rds_page_remainder_nb = {
+ .notifier_call = rds_page_remainder_cpu_notify,
+};
+
+void rds_page_exit(void)
+{
+ int i;
+
+ for_each_possible_cpu(i)
+ rds_page_remainder_cpu_notify(&rds_page_remainder_nb,
+ (unsigned long)CPU_DEAD,
+ (void *)(long)i);
+}
--
1.5.6.3
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