RDS: Message parsing

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@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andy Grover 2009-02-24 15:30:26 +00:00 committed by David S. Miller
parent 3e5048495c
commit 7875e18e09
2 changed files with 623 additions and 0 deletions

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net/rds/message.c Normal file
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/*
* 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);
}
/*
* 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);
}
}
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;
}
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;
}
/*
* 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));
}
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;
if (nents)
sg_init_table(rm->m_sg, nents);
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);
}

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/*
* 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;
}
/*
* 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);
}