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mirror_zfs/module/zfs/qat_compress.c
Tom Caputi 32dce2da0c Resolve QAT issues with incompressible data 
Currently, when ZFS wants to accelerate compression with QAT, it
passes a destination buffer of the same size as the source buffer.
Unfortunately, if the data is incompressible, QAT can actually
"compress" the data to be larger than the source buffer. When this
happens, the QAT driver will return a FAILED error code and print
warnings to dmesg. This patch fixes these issues by providing the
QAT driver with an additional buffer to work with so that even
completely incompressible source data will not cause an overflow.

This patch also resolves an error handling issue where
incompressible data attempts compression twice: once by QAT and
once in software. To fix this issue, a new (and fake) error code
CPA_STATUS_INOMPRESSIBLE has been added so that the calling code
can correctly account for the difference between a hardware
failure and data that simply cannot be compressed.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Weigang Li <weigang.li@intel.com>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes #7338
2018-03-29 17:40:34 -07:00

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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
#if defined(_KERNEL) && defined(HAVE_QAT)
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/completion.h>
#include <sys/zfs_context.h>
#include <sys/zio.h>
#include "qat.h"
/*
* Max instances in a QAT device, each instance is a channel to submit
* jobs to QAT hardware, this is only for pre-allocating instance and
* session arrays; the actual number of instances are defined in the
* QAT driver's configuration file.
*/
#define QAT_DC_MAX_INSTANCES 48
/*
* ZLIB head and foot size
*/
#define ZLIB_HEAD_SZ 2
#define ZLIB_FOOT_SZ 4
static CpaInstanceHandle dc_inst_handles[QAT_DC_MAX_INSTANCES];
static CpaDcSessionHandle session_handles[QAT_DC_MAX_INSTANCES];
static CpaBufferList **buffer_array[QAT_DC_MAX_INSTANCES];
static Cpa16U num_inst = 0;
static Cpa32U inst_num = 0;
static boolean_t qat_dc_init_done = B_FALSE;
int zfs_qat_compress_disable = 0;
boolean_t
qat_dc_use_accel(size_t s_len)
{
return (!zfs_qat_compress_disable &&
qat_dc_init_done &&
s_len >= QAT_MIN_BUF_SIZE &&
s_len <= QAT_MAX_BUF_SIZE);
}
static void
qat_dc_callback(void *p_callback, CpaStatus status)
{
if (p_callback != NULL)
complete((struct completion *)p_callback);
}
static void
qat_dc_clean(void)
{
Cpa16U buff_num = 0;
Cpa16U num_inter_buff_lists = 0;
Cpa16U i = 0;
for (i = 0; i < num_inst; i++) {
cpaDcStopInstance(dc_inst_handles[i]);
QAT_PHYS_CONTIG_FREE(session_handles[i]);
/* free intermediate buffers */
if (buffer_array[i] != NULL) {
cpaDcGetNumIntermediateBuffers(
dc_inst_handles[i], &num_inter_buff_lists);
for (buff_num = 0; buff_num < num_inter_buff_lists;
buff_num++) {
CpaBufferList *buffer_inter =
buffer_array[i][buff_num];
if (buffer_inter->pBuffers) {
QAT_PHYS_CONTIG_FREE(
buffer_inter->pBuffers->pData);
QAT_PHYS_CONTIG_FREE(
buffer_inter->pBuffers);
}
QAT_PHYS_CONTIG_FREE(
buffer_inter->pPrivateMetaData);
QAT_PHYS_CONTIG_FREE(buffer_inter);
}
}
}
num_inst = 0;
qat_dc_init_done = B_FALSE;
}
int
qat_dc_init(void)
{
CpaStatus status = CPA_STATUS_SUCCESS;
Cpa32U sess_size = 0;
Cpa32U ctx_size = 0;
Cpa16U num_inter_buff_lists = 0;
Cpa16U buff_num = 0;
Cpa32U buff_meta_size = 0;
CpaDcSessionSetupData sd = {0};
Cpa16U i;
status = cpaDcGetNumInstances(&num_inst);
if (status != CPA_STATUS_SUCCESS)
return (-1);
/* if the user has configured no QAT compression units just return */
if (num_inst == 0)
return (0);
if (num_inst > QAT_DC_MAX_INSTANCES)
num_inst = QAT_DC_MAX_INSTANCES;
status = cpaDcGetInstances(num_inst, &dc_inst_handles[0]);
if (status != CPA_STATUS_SUCCESS)
return (-1);
for (i = 0; i < num_inst; i++) {
cpaDcSetAddressTranslation(dc_inst_handles[i],
(void*)virt_to_phys);
status = cpaDcBufferListGetMetaSize(dc_inst_handles[i],
1, &buff_meta_size);
if (status == CPA_STATUS_SUCCESS)
status = cpaDcGetNumIntermediateBuffers(
dc_inst_handles[i], &num_inter_buff_lists);
if (status == CPA_STATUS_SUCCESS && num_inter_buff_lists != 0)
status = QAT_PHYS_CONTIG_ALLOC(&buffer_array[i],
num_inter_buff_lists *
sizeof (CpaBufferList *));
for (buff_num = 0; buff_num < num_inter_buff_lists;
buff_num++) {
if (status == CPA_STATUS_SUCCESS)
status = QAT_PHYS_CONTIG_ALLOC(
&buffer_array[i][buff_num],
sizeof (CpaBufferList));
if (status == CPA_STATUS_SUCCESS)
status = QAT_PHYS_CONTIG_ALLOC(
&buffer_array[i][buff_num]->
pPrivateMetaData,
buff_meta_size);
if (status == CPA_STATUS_SUCCESS)
status = QAT_PHYS_CONTIG_ALLOC(
&buffer_array[i][buff_num]->pBuffers,
sizeof (CpaFlatBuffer));
if (status == CPA_STATUS_SUCCESS) {
/*
* implementation requires an intermediate
* buffer approximately twice the size of
* output buffer, which is 2x max buffer
* size here.
*/
status = QAT_PHYS_CONTIG_ALLOC(
&buffer_array[i][buff_num]->pBuffers->
pData, 2 * QAT_MAX_BUF_SIZE);
if (status != CPA_STATUS_SUCCESS)
goto fail;
buffer_array[i][buff_num]->numBuffers = 1;
buffer_array[i][buff_num]->pBuffers->
dataLenInBytes = 2 * QAT_MAX_BUF_SIZE;
}
}
status = cpaDcStartInstance(dc_inst_handles[i],
num_inter_buff_lists, buffer_array[i]);
if (status != CPA_STATUS_SUCCESS)
goto fail;
sd.compLevel = CPA_DC_L1;
sd.compType = CPA_DC_DEFLATE;
sd.huffType = CPA_DC_HT_FULL_DYNAMIC;
sd.sessDirection = CPA_DC_DIR_COMBINED;
sd.sessState = CPA_DC_STATELESS;
sd.deflateWindowSize = 7;
sd.checksum = CPA_DC_ADLER32;
status = cpaDcGetSessionSize(dc_inst_handles[i],
&sd, &sess_size, &ctx_size);
if (status != CPA_STATUS_SUCCESS)
goto fail;
QAT_PHYS_CONTIG_ALLOC(&session_handles[i], sess_size);
if (session_handles[i] == NULL)
goto fail;
status = cpaDcInitSession(dc_inst_handles[i],
session_handles[i],
&sd, NULL, qat_dc_callback);
if (status != CPA_STATUS_SUCCESS)
goto fail;
}
qat_dc_init_done = B_TRUE;
return (0);
fail:
qat_dc_clean();
return (-1);
}
void
qat_dc_fini(void)
{
if (!qat_dc_init_done)
return;
qat_dc_clean();
}
/*
* The "add" parameter is an additional buffer which is passed
* to QAT as a scratch buffer alongside the destination buffer
* in case the "compressed" data ends up being larger than the
* original source data. This is necessary to prevent QAT from
* generating buffer overflow warnings for incompressible data.
*/
static int
qat_compress_impl(qat_compress_dir_t dir, char *src, int src_len,
char *dst, int dst_len, char *add, int add_len, size_t *c_len)
{
CpaInstanceHandle dc_inst_handle;
CpaDcSessionHandle session_handle;
CpaBufferList *buf_list_src = NULL;
CpaBufferList *buf_list_dst = NULL;
CpaFlatBuffer *flat_buf_src = NULL;
CpaFlatBuffer *flat_buf_dst = NULL;
Cpa8U *buffer_meta_src = NULL;
Cpa8U *buffer_meta_dst = NULL;
Cpa32U buffer_meta_size = 0;
CpaDcRqResults dc_results;
CpaStatus status = CPA_STATUS_SUCCESS;
Cpa32U hdr_sz = 0;
Cpa32U compressed_sz;
Cpa32U num_src_buf = (src_len >> PAGE_SHIFT) + 2;
Cpa32U num_dst_buf = (dst_len >> PAGE_SHIFT) + 2;
Cpa32U num_add_buf = (add_len >> PAGE_SHIFT) + 2;
Cpa32U bytes_left;
Cpa32U dst_pages = 0;
char *data;
struct page *page;
struct page **in_pages = NULL;
struct page **out_pages = NULL;
struct page **add_pages = NULL;
Cpa32U page_off = 0;
struct completion complete;
Cpa32U page_num = 0;
Cpa16U i;
/*
* We increment num_src_buf and num_dst_buf by 2 to allow
* us to handle non page-aligned buffer addresses and buffers
* whose sizes are not divisible by PAGE_SIZE.
*/
Cpa32U src_buffer_list_mem_size = sizeof (CpaBufferList) +
(num_src_buf * sizeof (CpaFlatBuffer));
Cpa32U dst_buffer_list_mem_size = sizeof (CpaBufferList) +
((num_dst_buf + num_add_buf) * sizeof (CpaFlatBuffer));
if (QAT_PHYS_CONTIG_ALLOC(&in_pages,
num_src_buf * sizeof (struct page *)) != CPA_STATUS_SUCCESS)
goto fail;
if (QAT_PHYS_CONTIG_ALLOC(&out_pages,
num_dst_buf * sizeof (struct page *)) != CPA_STATUS_SUCCESS)
goto fail;
if (QAT_PHYS_CONTIG_ALLOC(&add_pages,
num_add_buf * sizeof (struct page *)) != CPA_STATUS_SUCCESS)
goto fail;
i = atomic_inc_32_nv(&inst_num) % num_inst;
dc_inst_handle = dc_inst_handles[i];
session_handle = session_handles[i];
cpaDcBufferListGetMetaSize(dc_inst_handle, num_src_buf,
&buffer_meta_size);
if (QAT_PHYS_CONTIG_ALLOC(&buffer_meta_src, buffer_meta_size) !=
CPA_STATUS_SUCCESS)
goto fail;
cpaDcBufferListGetMetaSize(dc_inst_handle, num_dst_buf + num_add_buf,
&buffer_meta_size);
if (QAT_PHYS_CONTIG_ALLOC(&buffer_meta_dst, buffer_meta_size) !=
CPA_STATUS_SUCCESS)
goto fail;
/* build source buffer list */
if (QAT_PHYS_CONTIG_ALLOC(&buf_list_src, src_buffer_list_mem_size) !=
CPA_STATUS_SUCCESS)
goto fail;
flat_buf_src = (CpaFlatBuffer *)(buf_list_src + 1);
buf_list_src->pBuffers = flat_buf_src; /* always point to first one */
/* build destination buffer list */
if (QAT_PHYS_CONTIG_ALLOC(&buf_list_dst, dst_buffer_list_mem_size) !=
CPA_STATUS_SUCCESS)
goto fail;
flat_buf_dst = (CpaFlatBuffer *)(buf_list_dst + 1);
buf_list_dst->pBuffers = flat_buf_dst; /* always point to first one */
buf_list_src->numBuffers = 0;
buf_list_src->pPrivateMetaData = buffer_meta_src;
bytes_left = src_len;
data = src;
page_num = 0;
while (bytes_left > 0) {
page_off = ((long)data & ~PAGE_MASK);
page = qat_mem_to_page(data);
in_pages[page_num] = page;
flat_buf_src->pData = kmap(page) + page_off;
flat_buf_src->dataLenInBytes =
min((long)PAGE_SIZE - page_off, (long)bytes_left);
bytes_left -= flat_buf_src->dataLenInBytes;
data += flat_buf_src->dataLenInBytes;
flat_buf_src++;
buf_list_src->numBuffers++;
page_num++;
}
buf_list_dst->numBuffers = 0;
buf_list_dst->pPrivateMetaData = buffer_meta_dst;
bytes_left = dst_len;
data = dst;
page_num = 0;
while (bytes_left > 0) {
page_off = ((long)data & ~PAGE_MASK);
page = qat_mem_to_page(data);
flat_buf_dst->pData = kmap(page) + page_off;
out_pages[page_num] = page;
flat_buf_dst->dataLenInBytes =
min((long)PAGE_SIZE - page_off, (long)bytes_left);
bytes_left -= flat_buf_dst->dataLenInBytes;
data += flat_buf_dst->dataLenInBytes;
flat_buf_dst++;
buf_list_dst->numBuffers++;
page_num++;
dst_pages++;
}
/* map additional scratch pages into the destination buffer list */
bytes_left = add_len;
data = add;
page_num = 0;
while (bytes_left > 0) {
page_off = ((long)data & ~PAGE_MASK);
page = qat_mem_to_page(data);
flat_buf_dst->pData = kmap(page) + page_off;
add_pages[page_num] = page;
flat_buf_dst->dataLenInBytes =
min((long)PAGE_SIZE - page_off, (long)bytes_left);
bytes_left -= flat_buf_dst->dataLenInBytes;
data += flat_buf_dst->dataLenInBytes;
flat_buf_dst++;
buf_list_dst->numBuffers++;
page_num++;
}
init_completion(&complete);
if (dir == QAT_COMPRESS) {
QAT_STAT_BUMP(comp_requests);
QAT_STAT_INCR(comp_total_in_bytes, src_len);
cpaDcGenerateHeader(session_handle,
buf_list_dst->pBuffers, &hdr_sz);
buf_list_dst->pBuffers->pData += hdr_sz;
buf_list_dst->pBuffers->dataLenInBytes -= hdr_sz;
status = cpaDcCompressData(
dc_inst_handle, session_handle,
buf_list_src, buf_list_dst,
&dc_results, CPA_DC_FLUSH_FINAL,
&complete);
if (status != CPA_STATUS_SUCCESS) {
goto fail;
}
/* we now wait until the completion of the operation. */
if (!wait_for_completion_interruptible_timeout(&complete,
QAT_TIMEOUT_MS)) {
status = CPA_STATUS_FAIL;
goto fail;
}
if (dc_results.status != CPA_STATUS_SUCCESS) {
status = CPA_STATUS_FAIL;
goto fail;
}
compressed_sz = dc_results.produced;
if (compressed_sz + hdr_sz + ZLIB_FOOT_SZ > dst_len) {
status = CPA_STATUS_INCOMPRESSIBLE;
goto fail;
}
flat_buf_dst = (CpaFlatBuffer *)(buf_list_dst + 1);
/* move to the last page */
flat_buf_dst += (compressed_sz + hdr_sz) >> PAGE_SHIFT;
/* no space for gzip footer in the last page */
if (((compressed_sz + hdr_sz) % PAGE_SIZE)
+ ZLIB_FOOT_SZ > PAGE_SIZE) {
status = CPA_STATUS_INCOMPRESSIBLE;
goto fail;
}
/* jump to the end of the buffer and append footer */
flat_buf_dst->pData =
(char *)((unsigned long)flat_buf_dst->pData & PAGE_MASK)
+ ((compressed_sz + hdr_sz) % PAGE_SIZE);
flat_buf_dst->dataLenInBytes = ZLIB_FOOT_SZ;
dc_results.produced = 0;
status = cpaDcGenerateFooter(session_handle,
flat_buf_dst, &dc_results);
if (status != CPA_STATUS_SUCCESS)
goto fail;
*c_len = compressed_sz + dc_results.produced + hdr_sz;
QAT_STAT_INCR(comp_total_out_bytes, *c_len);
} else {
ASSERT3U(dir, ==, QAT_DECOMPRESS);
QAT_STAT_BUMP(decomp_requests);
QAT_STAT_INCR(decomp_total_in_bytes, src_len);
buf_list_src->pBuffers->pData += ZLIB_HEAD_SZ;
buf_list_src->pBuffers->dataLenInBytes -= ZLIB_HEAD_SZ;
status = cpaDcDecompressData(dc_inst_handle, session_handle,
buf_list_src, buf_list_dst, &dc_results, CPA_DC_FLUSH_FINAL,
&complete);
if (CPA_STATUS_SUCCESS != status) {
status = CPA_STATUS_FAIL;
goto fail;
}
/* we now wait until the completion of the operation. */
if (!wait_for_completion_interruptible_timeout(&complete,
QAT_TIMEOUT_MS)) {
status = CPA_STATUS_FAIL;
goto fail;
}
if (dc_results.status != CPA_STATUS_SUCCESS) {
status = CPA_STATUS_FAIL;
goto fail;
}
*c_len = dc_results.produced;
QAT_STAT_INCR(decomp_total_out_bytes, *c_len);
}
fail:
if (status != CPA_STATUS_SUCCESS && status != CPA_STATUS_INCOMPRESSIBLE)
QAT_STAT_BUMP(dc_fails);
if (in_pages) {
for (page_num = 0;
page_num < buf_list_src->numBuffers;
page_num++) {
kunmap(in_pages[page_num]);
}
QAT_PHYS_CONTIG_FREE(in_pages);
}
if (out_pages) {
for (page_num = 0; page_num < dst_pages; page_num++) {
kunmap(out_pages[page_num]);
}
QAT_PHYS_CONTIG_FREE(out_pages);
}
if (add_pages) {
for (page_num = 0;
page_num < buf_list_dst->numBuffers - dst_pages;
page_num++) {
kunmap(add_pages[page_num]);
}
QAT_PHYS_CONTIG_FREE(add_pages);
}
QAT_PHYS_CONTIG_FREE(buffer_meta_src);
QAT_PHYS_CONTIG_FREE(buffer_meta_dst);
QAT_PHYS_CONTIG_FREE(buf_list_src);
QAT_PHYS_CONTIG_FREE(buf_list_dst);
return (status);
}
/*
* Entry point for QAT accelerated compression / decompression.
*/
int
qat_compress(qat_compress_dir_t dir, char *src, int src_len,
char *dst, int dst_len, size_t *c_len)
{
int ret;
size_t add_len = 0;
void *add = NULL;
if (dir == QAT_COMPRESS) {
add_len = dst_len;
add = zio_data_buf_alloc(add_len);
}
ret = qat_compress_impl(dir, src, src_len, dst,
dst_len, add, add_len, c_len);
if (dir == QAT_COMPRESS)
zio_data_buf_free(add, add_len);
return (ret);
}
module_param(zfs_qat_compress_disable, int, 0644);
MODULE_PARM_DESC(zfs_qat_compress_disable, "Disable QAT compression");
#endif
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