linux-stable/drivers/target/target_core_user.c
Xiubo Li 141685a391 tcmu: Add dynamic growing data area feature support
Currently for the TCMU, the ring buffer size is fixed to 64K cmd
area + 1M data area, and this will be bottlenecks for high iops.

The struct tcmu_cmd_entry {} size is fixed about 112 bytes with
iovec[N] & N <= 4, and the size of struct iovec is about 16 bytes.

If N == 0, the ratio will be sizeof(cmd entry) : sizeof(datas) ==
112Bytes : (N * 4096)Bytes = 28 : 0, no data area is need.

If 0 < N <=4, the ratio will be sizeof(cmd entry) : sizeof(datas)
== 112Bytes : (N * 4096)Bytes = 28 : (N * 1024), so the max will
be 28 : 1024.

If N > 4, the sizeof(cmd entry) will be [(N - 4) *16 + 112] bytes,
and its corresponding data size will be [N * 4096], so the ratio
of sizeof(cmd entry) : sizeof(datas) == [(N - 4) * 16 + 112)Bytes
: (N * 4096)Bytes == 4/1024 - 12/(N * 1024), so the max is about
4 : 1024.

When N is bigger, the ratio will be smaller.

As the initial patch, we will set the cmd area size to 2M, and
the cmd area size to 32M. The TCMU will dynamically grows the data
area from 0 to max 32M size as needed.

The cmd area memory will be allocated through vmalloc(), and the
data area's blocks will be allocated individually later when needed.

The allocated data area block memory will be managed via radix tree.
For now the bitmap still be the most efficient way to search and
manage the block index, this could be update later.

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Jianfei Hu <hujianfei@cmss.chinamobile.com>
Acked-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2017-05-01 22:57:36 -07:00

1469 lines
36 KiB
C

/*
* Copyright (C) 2013 Shaohua Li <shli@kernel.org>
* Copyright (C) 2014 Red Hat, Inc.
* Copyright (C) 2015 Arrikto, Inc.
* Copyright (C) 2017 Chinamobile, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/parser.h>
#include <linux/vmalloc.h>
#include <linux/uio_driver.h>
#include <linux/radix-tree.h>
#include <linux/stringify.h>
#include <linux/bitops.h>
#include <linux/highmem.h>
#include <linux/configfs.h>
#include <net/genetlink.h>
#include <scsi/scsi_common.h>
#include <scsi/scsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_backend.h>
#include <linux/target_core_user.h>
/*
* Define a shared-memory interface for LIO to pass SCSI commands and
* data to userspace for processing. This is to allow backends that
* are too complex for in-kernel support to be possible.
*
* It uses the UIO framework to do a lot of the device-creation and
* introspection work for us.
*
* See the .h file for how the ring is laid out. Note that while the
* command ring is defined, the particulars of the data area are
* not. Offset values in the command entry point to other locations
* internal to the mmap()ed area. There is separate space outside the
* command ring for data buffers. This leaves maximum flexibility for
* moving buffer allocations, or even page flipping or other
* allocation techniques, without altering the command ring layout.
*
* SECURITY:
* The user process must be assumed to be malicious. There's no way to
* prevent it breaking the command ring protocol if it wants, but in
* order to prevent other issues we must only ever read *data* from
* the shared memory area, not offsets or sizes. This applies to
* command ring entries as well as the mailbox. Extra code needed for
* this may have a 'UAM' comment.
*/
#define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
/* For cmd area, the size is fixed 2M */
#define CMDR_SIZE (2 * 1024 * 1024)
/* For data area, the size is fixed 32M */
#define DATA_BLOCK_BITS (8 * 1024)
#define DATA_BLOCK_SIZE 4096
#define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
/* The ring buffer size is 34M */
#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
static struct device *tcmu_root_device;
struct tcmu_hba {
u32 host_id;
};
#define TCMU_CONFIG_LEN 256
struct tcmu_dev {
struct se_device se_dev;
char *name;
struct se_hba *hba;
#define TCMU_DEV_BIT_OPEN 0
#define TCMU_DEV_BIT_BROKEN 1
unsigned long flags;
struct uio_info uio_info;
struct tcmu_mailbox *mb_addr;
size_t dev_size;
u32 cmdr_size;
u32 cmdr_last_cleaned;
/* Offset of data area from start of mb */
/* Must add data_off and mb_addr to get the address */
size_t data_off;
size_t data_size;
wait_queue_head_t wait_cmdr;
/* TODO should this be a mutex? */
spinlock_t cmdr_lock;
uint32_t dbi_max;
DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
struct radix_tree_root data_blocks;
struct idr commands;
spinlock_t commands_lock;
struct timer_list timeout;
unsigned int cmd_time_out;
char dev_config[TCMU_CONFIG_LEN];
};
#define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
#define CMDR_OFF sizeof(struct tcmu_mailbox)
struct tcmu_cmd {
struct se_cmd *se_cmd;
struct tcmu_dev *tcmu_dev;
uint16_t cmd_id;
/* Can't use se_cmd when cleaning up expired cmds, because if
cmd has been completed then accessing se_cmd is off limits */
uint32_t dbi_cnt;
uint32_t dbi_cur;
uint32_t *dbi;
unsigned long deadline;
#define TCMU_CMD_BIT_EXPIRED 0
unsigned long flags;
};
static struct kmem_cache *tcmu_cmd_cache;
/* multicast group */
enum tcmu_multicast_groups {
TCMU_MCGRP_CONFIG,
};
static const struct genl_multicast_group tcmu_mcgrps[] = {
[TCMU_MCGRP_CONFIG] = { .name = "config", },
};
/* Our generic netlink family */
static struct genl_family tcmu_genl_family __ro_after_init = {
.module = THIS_MODULE,
.hdrsize = 0,
.name = "TCM-USER",
.version = 1,
.maxattr = TCMU_ATTR_MAX,
.mcgrps = tcmu_mcgrps,
.n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
.netnsok = true,
};
#define tcmu_cmd_set_dbi_cur(cmd, index) ((cmd)->dbi_cur = (index))
#define tcmu_cmd_reset_dbi_cur(cmd) tcmu_cmd_set_dbi_cur(cmd, 0)
#define tcmu_cmd_set_dbi(cmd, index) ((cmd)->dbi[(cmd)->dbi_cur++] = (index))
#define tcmu_cmd_get_dbi(cmd) ((cmd)->dbi[(cmd)->dbi_cur++])
static void tcmu_cmd_free_data(struct tcmu_cmd *tcmu_cmd)
{
struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
uint32_t i;
for (i = 0; i < tcmu_cmd->dbi_cnt; i++)
clear_bit(tcmu_cmd->dbi[i], udev->data_bitmap);
}
static int tcmu_get_empty_block(struct tcmu_dev *udev, void **addr)
{
void *p;
uint32_t dbi;
int ret;
dbi = find_first_zero_bit(udev->data_bitmap, DATA_BLOCK_BITS);
if (dbi > udev->dbi_max)
udev->dbi_max = dbi;
set_bit(dbi, udev->data_bitmap);
p = radix_tree_lookup(&udev->data_blocks, dbi);
if (!p) {
p = kzalloc(DATA_BLOCK_SIZE, GFP_ATOMIC);
if (!p) {
clear_bit(dbi, udev->data_bitmap);
return -ENOMEM;
}
ret = radix_tree_insert(&udev->data_blocks, dbi, p);
if (ret) {
kfree(p);
clear_bit(dbi, udev->data_bitmap);
return ret;
}
}
*addr = p;
return dbi;
}
static void *tcmu_get_block_addr(struct tcmu_dev *udev, uint32_t dbi)
{
return radix_tree_lookup(&udev->data_blocks, dbi);
}
static inline void tcmu_free_cmd(struct tcmu_cmd *tcmu_cmd)
{
kfree(tcmu_cmd->dbi);
kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
}
static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
{
struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE);
if (se_cmd->se_cmd_flags & SCF_BIDI) {
BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
data_length += round_up(se_cmd->t_bidi_data_sg->length,
DATA_BLOCK_SIZE);
}
return data_length;
}
static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd)
{
size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
return data_length / DATA_BLOCK_SIZE;
}
static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
{
struct se_device *se_dev = se_cmd->se_dev;
struct tcmu_dev *udev = TCMU_DEV(se_dev);
struct tcmu_cmd *tcmu_cmd;
int cmd_id;
tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
if (!tcmu_cmd)
return NULL;
tcmu_cmd->se_cmd = se_cmd;
tcmu_cmd->tcmu_dev = udev;
if (udev->cmd_time_out)
tcmu_cmd->deadline = jiffies +
msecs_to_jiffies(udev->cmd_time_out);
tcmu_cmd_reset_dbi_cur(tcmu_cmd);
tcmu_cmd->dbi_cnt = tcmu_cmd_get_block_cnt(tcmu_cmd);
tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
GFP_KERNEL);
if (!tcmu_cmd->dbi) {
kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
return NULL;
}
idr_preload(GFP_KERNEL);
spin_lock_irq(&udev->commands_lock);
cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
USHRT_MAX, GFP_NOWAIT);
spin_unlock_irq(&udev->commands_lock);
idr_preload_end();
if (cmd_id < 0) {
tcmu_free_cmd(tcmu_cmd);
return NULL;
}
tcmu_cmd->cmd_id = cmd_id;
return tcmu_cmd;
}
static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
{
unsigned long offset = offset_in_page(vaddr);
size = round_up(size+offset, PAGE_SIZE);
vaddr -= offset;
while (size) {
flush_dcache_page(virt_to_page(vaddr));
size -= PAGE_SIZE;
}
}
/*
* Some ring helper functions. We don't assume size is a power of 2 so
* we can't use circ_buf.h.
*/
static inline size_t spc_used(size_t head, size_t tail, size_t size)
{
int diff = head - tail;
if (diff >= 0)
return diff;
else
return size + diff;
}
static inline size_t spc_free(size_t head, size_t tail, size_t size)
{
/* Keep 1 byte unused or we can't tell full from empty */
return (size - spc_used(head, tail, size) - 1);
}
static inline size_t head_to_end(size_t head, size_t size)
{
return size - head;
}
static inline void new_iov(struct iovec **iov, int *iov_cnt,
struct tcmu_dev *udev)
{
struct iovec *iovec;
if (*iov_cnt != 0)
(*iov)++;
(*iov_cnt)++;
iovec = *iov;
memset(iovec, 0, sizeof(struct iovec));
}
#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
/* offset is relative to mb_addr */
static inline size_t get_block_offset_user(struct tcmu_dev *dev,
int dbi, int remaining)
{
return dev->data_off + dbi * DATA_BLOCK_SIZE +
DATA_BLOCK_SIZE - remaining;
}
static inline size_t iov_tail(struct tcmu_dev *udev, struct iovec *iov)
{
return (size_t)iov->iov_base + iov->iov_len;
}
static int alloc_and_scatter_data_area(struct tcmu_dev *udev,
struct tcmu_cmd *tcmu_cmd, struct scatterlist *data_sg,
unsigned int data_nents, struct iovec **iov,
int *iov_cnt, bool copy_data)
{
int i, dbi;
int block_remaining = 0;
void *from, *to = NULL;
size_t copy_bytes, to_offset, offset;
struct scatterlist *sg;
for_each_sg(data_sg, sg, data_nents, i) {
int sg_remaining = sg->length;
from = kmap_atomic(sg_page(sg)) + sg->offset;
while (sg_remaining > 0) {
if (block_remaining == 0) {
block_remaining = DATA_BLOCK_SIZE;
dbi = tcmu_get_empty_block(udev, &to);
if (dbi < 0) {
kunmap_atomic(from - sg->offset);
return dbi;
}
tcmu_cmd_set_dbi(tcmu_cmd, dbi);
}
copy_bytes = min_t(size_t, sg_remaining,
block_remaining);
to_offset = get_block_offset_user(udev, dbi,
block_remaining);
offset = DATA_BLOCK_SIZE - block_remaining;
to = (void *)(unsigned long)to + offset;
if (*iov_cnt != 0 &&
to_offset == iov_tail(udev, *iov)) {
(*iov)->iov_len += copy_bytes;
} else {
new_iov(iov, iov_cnt, udev);
(*iov)->iov_base = (void __user *)to_offset;
(*iov)->iov_len = copy_bytes;
}
if (copy_data) {
memcpy(to, from + sg->length - sg_remaining,
copy_bytes);
tcmu_flush_dcache_range(to, copy_bytes);
}
sg_remaining -= copy_bytes;
block_remaining -= copy_bytes;
}
kunmap_atomic(from - sg->offset);
}
return 0;
}
static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
bool bidi)
{
struct se_cmd *se_cmd = cmd->se_cmd;
int i, dbi;
int block_remaining = 0;
void *from, *to;
size_t copy_bytes, offset;
struct scatterlist *sg, *data_sg;
unsigned int data_nents;
uint32_t count = 0;
if (!bidi) {
data_sg = se_cmd->t_data_sg;
data_nents = se_cmd->t_data_nents;
} else {
/*
* For bidi case, the first count blocks are for Data-Out
* buffer blocks, and before gathering the Data-In buffer
* the Data-Out buffer blocks should be discarded.
*/
count = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
data_sg = se_cmd->t_bidi_data_sg;
data_nents = se_cmd->t_bidi_data_nents;
}
tcmu_cmd_set_dbi_cur(cmd, count);
for_each_sg(data_sg, sg, data_nents, i) {
int sg_remaining = sg->length;
to = kmap_atomic(sg_page(sg)) + sg->offset;
while (sg_remaining > 0) {
if (block_remaining == 0) {
block_remaining = DATA_BLOCK_SIZE;
dbi = tcmu_cmd_get_dbi(cmd);
from = tcmu_get_block_addr(udev, dbi);
}
copy_bytes = min_t(size_t, sg_remaining,
block_remaining);
offset = DATA_BLOCK_SIZE - block_remaining;
from = (void *)(unsigned long)from + offset;
tcmu_flush_dcache_range(from, copy_bytes);
memcpy(to + sg->length - sg_remaining, from,
copy_bytes);
sg_remaining -= copy_bytes;
block_remaining -= copy_bytes;
}
kunmap_atomic(to - sg->offset);
}
}
static inline size_t spc_bitmap_free(unsigned long *bitmap)
{
return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
bitmap_weight(bitmap, DATA_BLOCK_BITS));
}
/*
* We can't queue a command until we have space available on the cmd ring *and*
* space available on the data area.
*
* Called with ring lock held.
*/
static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
{
struct tcmu_mailbox *mb = udev->mb_addr;
size_t space, cmd_needed;
u32 cmd_head;
tcmu_flush_dcache_range(mb, sizeof(*mb));
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
/*
* If cmd end-of-ring space is too small then we need space for a NOP plus
* original cmd - cmds are internally contiguous.
*/
if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
cmd_needed = cmd_size;
else
cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
if (space < cmd_needed) {
pr_debug("no cmd space: %u %u %u\n", cmd_head,
udev->cmdr_last_cleaned, udev->cmdr_size);
return false;
}
space = spc_bitmap_free(udev->data_bitmap);
if (space < data_needed) {
pr_debug("no data space: only %zu available, but ask for %zu\n",
space, data_needed);
return false;
}
return true;
}
static sense_reason_t
tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
{
struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
size_t base_command_size, command_size;
struct tcmu_mailbox *mb;
struct tcmu_cmd_entry *entry;
struct iovec *iov;
int iov_cnt, ret;
uint32_t cmd_head;
uint64_t cdb_off;
bool copy_to_data_area;
size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
/*
* Must be a certain minimum size for response sense info, but
* also may be larger if the iov array is large.
*
* We prepare way too many iovs for potential uses here, because it's
* expensive to tell how many regions are freed in the bitmap
*/
base_command_size = max(offsetof(struct tcmu_cmd_entry,
req.iov[tcmu_cmd_get_block_cnt(tcmu_cmd)]),
sizeof(struct tcmu_cmd_entry));
command_size = base_command_size
+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
spin_lock_irq(&udev->cmdr_lock);
mb = udev->mb_addr;
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
if ((command_size > (udev->cmdr_size / 2)) ||
data_length > udev->data_size) {
pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
"cmd ring/data area\n", command_size, data_length,
udev->cmdr_size, udev->data_size);
spin_unlock_irq(&udev->cmdr_lock);
return TCM_INVALID_CDB_FIELD;
}
while (!is_ring_space_avail(udev, command_size, data_length)) {
int ret;
DEFINE_WAIT(__wait);
prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
pr_debug("sleeping for ring space\n");
spin_unlock_irq(&udev->cmdr_lock);
if (udev->cmd_time_out)
ret = schedule_timeout(
msecs_to_jiffies(udev->cmd_time_out));
else
ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
finish_wait(&udev->wait_cmdr, &__wait);
if (!ret) {
pr_warn("tcmu: command timed out\n");
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
spin_lock_irq(&udev->cmdr_lock);
/* We dropped cmdr_lock, cmd_head is stale */
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
}
/* Insert a PAD if end-of-ring space is too small */
if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
entry = (void *) mb + CMDR_OFF + cmd_head;
tcmu_flush_dcache_range(entry, sizeof(*entry));
tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
entry->hdr.cmd_id = 0; /* not used for PAD */
entry->hdr.kflags = 0;
entry->hdr.uflags = 0;
UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
WARN_ON(cmd_head != 0);
}
entry = (void *) mb + CMDR_OFF + cmd_head;
tcmu_flush_dcache_range(entry, sizeof(*entry));
tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
entry->hdr.cmd_id = tcmu_cmd->cmd_id;
entry->hdr.kflags = 0;
entry->hdr.uflags = 0;
/* Handle allocating space from the data area */
iov = &entry->req.iov[0];
iov_cnt = 0;
copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
|| se_cmd->se_cmd_flags & SCF_BIDI);
ret = alloc_and_scatter_data_area(udev, tcmu_cmd,
se_cmd->t_data_sg, se_cmd->t_data_nents,
&iov, &iov_cnt, copy_to_data_area);
if (ret) {
spin_unlock_irq(&udev->cmdr_lock);
pr_err("tcmu: alloc and scatter data failed\n");
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
entry->req.iov_cnt = iov_cnt;
entry->req.iov_dif_cnt = 0;
/* Handle BIDI commands */
if (se_cmd->se_cmd_flags & SCF_BIDI) {
iov_cnt = 0;
iov++;
ret = alloc_and_scatter_data_area(udev, tcmu_cmd,
se_cmd->t_bidi_data_sg,
se_cmd->t_bidi_data_nents,
&iov, &iov_cnt, false);
if (ret) {
spin_unlock_irq(&udev->cmdr_lock);
pr_err("tcmu: alloc and scatter bidi data failed\n");
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
entry->req.iov_bidi_cnt = iov_cnt;
}
/* All offsets relative to mb_addr, not start of entry! */
cdb_off = CMDR_OFF + cmd_head + base_command_size;
memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
entry->req.cdb_off = cdb_off;
tcmu_flush_dcache_range(entry, sizeof(*entry));
UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
tcmu_flush_dcache_range(mb, sizeof(*mb));
spin_unlock_irq(&udev->cmdr_lock);
/* TODO: only if FLUSH and FUA? */
uio_event_notify(&udev->uio_info);
if (udev->cmd_time_out)
mod_timer(&udev->timeout, round_jiffies_up(jiffies +
msecs_to_jiffies(udev->cmd_time_out)));
return TCM_NO_SENSE;
}
static sense_reason_t
tcmu_queue_cmd(struct se_cmd *se_cmd)
{
struct se_device *se_dev = se_cmd->se_dev;
struct tcmu_dev *udev = TCMU_DEV(se_dev);
struct tcmu_cmd *tcmu_cmd;
sense_reason_t ret;
tcmu_cmd = tcmu_alloc_cmd(se_cmd);
if (!tcmu_cmd)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
ret = tcmu_queue_cmd_ring(tcmu_cmd);
if (ret != TCM_NO_SENSE) {
pr_err("TCMU: Could not queue command\n");
spin_lock_irq(&udev->commands_lock);
idr_remove(&udev->commands, tcmu_cmd->cmd_id);
spin_unlock_irq(&udev->commands_lock);
tcmu_free_cmd(tcmu_cmd);
}
return ret;
}
static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
{
struct se_cmd *se_cmd = cmd->se_cmd;
struct tcmu_dev *udev = cmd->tcmu_dev;
/*
* cmd has been completed already from timeout, just reclaim
* data area space and free cmd
*/
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
goto out;
tcmu_cmd_reset_dbi_cur(cmd);
if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
cmd->se_cmd);
entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
} else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
se_cmd->scsi_sense_length);
} else if (se_cmd->se_cmd_flags & SCF_BIDI) {
/* Get Data-In buffer before clean up */
gather_data_area(udev, cmd, true);
} else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
gather_data_area(udev, cmd, false);
} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
/* TODO: */
} else if (se_cmd->data_direction != DMA_NONE) {
pr_warn("TCMU: data direction was %d!\n",
se_cmd->data_direction);
}
target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
out:
cmd->se_cmd = NULL;
tcmu_cmd_free_data(cmd);
tcmu_free_cmd(cmd);
}
static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
{
struct tcmu_mailbox *mb;
unsigned long flags;
int handled = 0;
if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
pr_err("ring broken, not handling completions\n");
return 0;
}
spin_lock_irqsave(&udev->cmdr_lock, flags);
mb = udev->mb_addr;
tcmu_flush_dcache_range(mb, sizeof(*mb));
while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
struct tcmu_cmd *cmd;
tcmu_flush_dcache_range(entry, sizeof(*entry));
if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
UPDATE_HEAD(udev->cmdr_last_cleaned,
tcmu_hdr_get_len(entry->hdr.len_op),
udev->cmdr_size);
continue;
}
WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
spin_lock(&udev->commands_lock);
cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
spin_unlock(&udev->commands_lock);
if (!cmd) {
pr_err("cmd_id not found, ring is broken\n");
set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
break;
}
tcmu_handle_completion(cmd, entry);
UPDATE_HEAD(udev->cmdr_last_cleaned,
tcmu_hdr_get_len(entry->hdr.len_op),
udev->cmdr_size);
handled++;
}
if (mb->cmd_tail == mb->cmd_head)
del_timer(&udev->timeout); /* no more pending cmds */
spin_unlock_irqrestore(&udev->cmdr_lock, flags);
wake_up(&udev->wait_cmdr);
return handled;
}
static int tcmu_check_expired_cmd(int id, void *p, void *data)
{
struct tcmu_cmd *cmd = p;
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
return 0;
if (!time_after(jiffies, cmd->deadline))
return 0;
set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
cmd->se_cmd = NULL;
return 0;
}
static void tcmu_device_timedout(unsigned long data)
{
struct tcmu_dev *udev = (struct tcmu_dev *)data;
unsigned long flags;
int handled;
handled = tcmu_handle_completions(udev);
pr_warn("%d completions handled from timeout\n", handled);
spin_lock_irqsave(&udev->commands_lock, flags);
idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
spin_unlock_irqrestore(&udev->commands_lock, flags);
/*
* We don't need to wakeup threads on wait_cmdr since they have their
* own timeout.
*/
}
static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
{
struct tcmu_hba *tcmu_hba;
tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
if (!tcmu_hba)
return -ENOMEM;
tcmu_hba->host_id = host_id;
hba->hba_ptr = tcmu_hba;
return 0;
}
static void tcmu_detach_hba(struct se_hba *hba)
{
kfree(hba->hba_ptr);
hba->hba_ptr = NULL;
}
static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
{
struct tcmu_dev *udev;
udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
if (!udev)
return NULL;
udev->name = kstrdup(name, GFP_KERNEL);
if (!udev->name) {
kfree(udev);
return NULL;
}
udev->hba = hba;
udev->cmd_time_out = TCMU_TIME_OUT;
init_waitqueue_head(&udev->wait_cmdr);
spin_lock_init(&udev->cmdr_lock);
idr_init(&udev->commands);
spin_lock_init(&udev->commands_lock);
setup_timer(&udev->timeout, tcmu_device_timedout,
(unsigned long)udev);
return &udev->se_dev;
}
static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
{
struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
tcmu_handle_completions(tcmu_dev);
return 0;
}
static void tcmu_blocks_release(struct tcmu_dev *udev, bool release_pending)
{
uint32_t dbi, end;
void *addr;
spin_lock_irq(&udev->cmdr_lock);
end = udev->dbi_max + 1;
/* try to release all unused blocks */
dbi = find_first_zero_bit(udev->data_bitmap, end);
if (dbi >= end) {
spin_unlock_irq(&udev->cmdr_lock);
return;
}
do {
addr = radix_tree_delete(&udev->data_blocks, dbi);
kfree(addr);
dbi = find_next_zero_bit(udev->data_bitmap, end, dbi + 1);
} while (dbi < end);
if (!release_pending)
return;
/* try to release all pending blocks */
dbi = find_first_bit(udev->data_bitmap, end);
if (dbi >= end) {
spin_unlock_irq(&udev->cmdr_lock);
return;
}
do {
addr = radix_tree_delete(&udev->data_blocks, dbi);
kfree(addr);
dbi = find_next_bit(udev->data_bitmap, end, dbi + 1);
} while (dbi < end);
spin_unlock_irq(&udev->cmdr_lock);
}
static void tcmu_vma_close(struct vm_area_struct *vma)
{
struct tcmu_dev *udev = vma->vm_private_data;
tcmu_blocks_release(udev, false);
}
/*
* mmap code from uio.c. Copied here because we want to hook mmap()
* and this stuff must come along.
*/
static int tcmu_find_mem_index(struct vm_area_struct *vma)
{
struct tcmu_dev *udev = vma->vm_private_data;
struct uio_info *info = &udev->uio_info;
if (vma->vm_pgoff < MAX_UIO_MAPS) {
if (info->mem[vma->vm_pgoff].size == 0)
return -1;
return (int)vma->vm_pgoff;
}
return -1;
}
static int tcmu_vma_fault(struct vm_fault *vmf)
{
struct tcmu_dev *udev = vmf->vma->vm_private_data;
struct uio_info *info = &udev->uio_info;
struct page *page;
unsigned long offset;
void *addr;
int mi = tcmu_find_mem_index(vmf->vma);
if (mi < 0)
return VM_FAULT_SIGBUS;
/*
* We need to subtract mi because userspace uses offset = N*PAGE_SIZE
* to use mem[N].
*/
offset = (vmf->pgoff - mi) << PAGE_SHIFT;
if (offset < udev->data_off) {
/* For the vmalloc()ed cmd area pages */
addr = (void *)(unsigned long)info->mem[mi].addr + offset;
page = vmalloc_to_page(addr);
} else {
/* For the dynamically growing data area pages */
uint32_t dbi;
dbi = (offset - udev->data_off) / DATA_BLOCK_SIZE;
addr = tcmu_get_block_addr(udev, dbi);
if (!addr)
return VM_FAULT_NOPAGE;
page = virt_to_page(addr);
}
get_page(page);
vmf->page = page;
return 0;
}
static const struct vm_operations_struct tcmu_vm_ops = {
.close = tcmu_vma_close,
.fault = tcmu_vma_fault,
};
static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = &tcmu_vm_ops;
vma->vm_private_data = udev;
/* Ensure the mmap is exactly the right size */
if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
return -EINVAL;
return 0;
}
static int tcmu_open(struct uio_info *info, struct inode *inode)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
/* O_EXCL not supported for char devs, so fake it? */
if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
return -EBUSY;
pr_debug("open\n");
return 0;
}
static int tcmu_release(struct uio_info *info, struct inode *inode)
{
struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
pr_debug("close\n");
return 0;
}
static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
{
struct sk_buff *skb;
void *msg_header;
int ret = -ENOMEM;
skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
if (!skb)
return ret;
msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
if (!msg_header)
goto free_skb;
ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
if (ret < 0)
goto free_skb;
ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
if (ret < 0)
goto free_skb;
genlmsg_end(skb, msg_header);
ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
TCMU_MCGRP_CONFIG, GFP_KERNEL);
/* We don't care if no one is listening */
if (ret == -ESRCH)
ret = 0;
return ret;
free_skb:
nlmsg_free(skb);
return ret;
}
static int tcmu_configure_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
struct tcmu_hba *hba = udev->hba->hba_ptr;
struct uio_info *info;
struct tcmu_mailbox *mb;
size_t size;
size_t used;
int ret = 0;
char *str;
info = &udev->uio_info;
size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
udev->dev_config);
size += 1; /* for \0 */
str = kmalloc(size, GFP_KERNEL);
if (!str)
return -ENOMEM;
used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
if (udev->dev_config[0])
snprintf(str + used, size - used, "/%s", udev->dev_config);
info->name = str;
udev->mb_addr = vzalloc(CMDR_SIZE);
if (!udev->mb_addr) {
ret = -ENOMEM;
goto err_vzalloc;
}
/* mailbox fits in first part of CMDR space */
udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
udev->data_off = CMDR_SIZE;
udev->data_size = DATA_SIZE;
/* Initialise the mailbox of the ring buffer */
mb = udev->mb_addr;
mb->version = TCMU_MAILBOX_VERSION;
mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
mb->cmdr_off = CMDR_OFF;
mb->cmdr_size = udev->cmdr_size;
WARN_ON(!PAGE_ALIGNED(udev->data_off));
WARN_ON(udev->data_size % PAGE_SIZE);
WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
INIT_RADIX_TREE(&udev->data_blocks, GFP_ATOMIC);
info->version = __stringify(TCMU_MAILBOX_VERSION);
info->mem[0].name = "tcm-user command & data buffer";
info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
info->mem[0].size = TCMU_RING_SIZE;
info->mem[0].memtype = UIO_MEM_NONE;
info->irqcontrol = tcmu_irqcontrol;
info->irq = UIO_IRQ_CUSTOM;
info->mmap = tcmu_mmap;
info->open = tcmu_open;
info->release = tcmu_release;
ret = uio_register_device(tcmu_root_device, info);
if (ret)
goto err_register;
/* User can set hw_block_size before enable the device */
if (dev->dev_attrib.hw_block_size == 0)
dev->dev_attrib.hw_block_size = 512;
/* Other attributes can be configured in userspace */
if (!dev->dev_attrib.hw_max_sectors)
dev->dev_attrib.hw_max_sectors = 128;
dev->dev_attrib.hw_queue_depth = 128;
ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
udev->uio_info.uio_dev->minor);
if (ret)
goto err_netlink;
return 0;
err_netlink:
uio_unregister_device(&udev->uio_info);
err_register:
vfree(udev->mb_addr);
err_vzalloc:
kfree(info->name);
return ret;
}
static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
{
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
kmem_cache_free(tcmu_cmd_cache, cmd);
return 0;
}
return -EINVAL;
}
static void tcmu_dev_call_rcu(struct rcu_head *p)
{
struct se_device *dev = container_of(p, struct se_device, rcu_head);
struct tcmu_dev *udev = TCMU_DEV(dev);
kfree(udev);
}
static bool tcmu_dev_configured(struct tcmu_dev *udev)
{
return udev->uio_info.uio_dev ? true : false;
}
static void tcmu_free_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
struct tcmu_cmd *cmd;
bool all_expired = true;
int i;
del_timer_sync(&udev->timeout);
vfree(udev->mb_addr);
/* Upper layer should drain all requests before calling this */
spin_lock_irq(&udev->commands_lock);
idr_for_each_entry(&udev->commands, cmd, i) {
if (tcmu_check_and_free_pending_cmd(cmd) != 0)
all_expired = false;
}
idr_destroy(&udev->commands);
spin_unlock_irq(&udev->commands_lock);
WARN_ON(!all_expired);
tcmu_blocks_release(udev, true);
if (tcmu_dev_configured(udev)) {
tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
udev->uio_info.uio_dev->minor);
uio_unregister_device(&udev->uio_info);
kfree(udev->uio_info.name);
kfree(udev->name);
}
call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
}
enum {
Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
Opt_err,
};
static match_table_t tokens = {
{Opt_dev_config, "dev_config=%s"},
{Opt_dev_size, "dev_size=%u"},
{Opt_hw_block_size, "hw_block_size=%u"},
{Opt_hw_max_sectors, "hw_max_sectors=%u"},
{Opt_err, NULL}
};
static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
{
unsigned long tmp_ul;
char *arg_p;
int ret;
arg_p = match_strdup(arg);
if (!arg_p)
return -ENOMEM;
ret = kstrtoul(arg_p, 0, &tmp_ul);
kfree(arg_p);
if (ret < 0) {
pr_err("kstrtoul() failed for dev attrib\n");
return ret;
}
if (!tmp_ul) {
pr_err("dev attrib must be nonzero\n");
return -EINVAL;
}
*dev_attrib = tmp_ul;
return 0;
}
static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
const char *page, ssize_t count)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
char *orig, *ptr, *opts, *arg_p;
substring_t args[MAX_OPT_ARGS];
int ret = 0, token;
opts = kstrdup(page, GFP_KERNEL);
if (!opts)
return -ENOMEM;
orig = opts;
while ((ptr = strsep(&opts, ",\n")) != NULL) {
if (!*ptr)
continue;
token = match_token(ptr, tokens, args);
switch (token) {
case Opt_dev_config:
if (match_strlcpy(udev->dev_config, &args[0],
TCMU_CONFIG_LEN) == 0) {
ret = -EINVAL;
break;
}
pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
break;
case Opt_dev_size:
arg_p = match_strdup(&args[0]);
if (!arg_p) {
ret = -ENOMEM;
break;
}
ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
kfree(arg_p);
if (ret < 0)
pr_err("kstrtoul() failed for dev_size=\n");
break;
case Opt_hw_block_size:
ret = tcmu_set_dev_attrib(&args[0],
&(dev->dev_attrib.hw_block_size));
break;
case Opt_hw_max_sectors:
ret = tcmu_set_dev_attrib(&args[0],
&(dev->dev_attrib.hw_max_sectors));
break;
default:
break;
}
if (ret)
break;
}
kfree(orig);
return (!ret) ? count : ret;
}
static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
ssize_t bl = 0;
bl = sprintf(b + bl, "Config: %s ",
udev->dev_config[0] ? udev->dev_config : "NULL");
bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
return bl;
}
static sector_t tcmu_get_blocks(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
return div_u64(udev->dev_size - dev->dev_attrib.block_size,
dev->dev_attrib.block_size);
}
static sense_reason_t
tcmu_parse_cdb(struct se_cmd *cmd)
{
return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
}
static ssize_t tcmu_cmd_time_out_show(struct config_item *item, char *page)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
struct se_dev_attrib, da_group);
struct tcmu_dev *udev = container_of(da->da_dev,
struct tcmu_dev, se_dev);
return snprintf(page, PAGE_SIZE, "%lu\n", udev->cmd_time_out / MSEC_PER_SEC);
}
static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *page,
size_t count)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
struct se_dev_attrib, da_group);
struct tcmu_dev *udev = container_of(da->da_dev,
struct tcmu_dev, se_dev);
u32 val;
int ret;
if (da->da_dev->export_count) {
pr_err("Unable to set tcmu cmd_time_out while exports exist\n");
return -EINVAL;
}
ret = kstrtou32(page, 0, &val);
if (ret < 0)
return ret;
udev->cmd_time_out = val * MSEC_PER_SEC;
return count;
}
CONFIGFS_ATTR(tcmu_, cmd_time_out);
static struct configfs_attribute **tcmu_attrs;
static struct target_backend_ops tcmu_ops = {
.name = "user",
.owner = THIS_MODULE,
.transport_flags = TRANSPORT_FLAG_PASSTHROUGH,
.attach_hba = tcmu_attach_hba,
.detach_hba = tcmu_detach_hba,
.alloc_device = tcmu_alloc_device,
.configure_device = tcmu_configure_device,
.free_device = tcmu_free_device,
.parse_cdb = tcmu_parse_cdb,
.set_configfs_dev_params = tcmu_set_configfs_dev_params,
.show_configfs_dev_params = tcmu_show_configfs_dev_params,
.get_device_type = sbc_get_device_type,
.get_blocks = tcmu_get_blocks,
.tb_dev_attrib_attrs = NULL,
};
static int __init tcmu_module_init(void)
{
int ret, i, len = 0;
BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
sizeof(struct tcmu_cmd),
__alignof__(struct tcmu_cmd),
0, NULL);
if (!tcmu_cmd_cache)
return -ENOMEM;
tcmu_root_device = root_device_register("tcm_user");
if (IS_ERR(tcmu_root_device)) {
ret = PTR_ERR(tcmu_root_device);
goto out_free_cache;
}
ret = genl_register_family(&tcmu_genl_family);
if (ret < 0) {
goto out_unreg_device;
}
for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
len += sizeof(struct configfs_attribute *);
}
len += sizeof(struct configfs_attribute *) * 2;
tcmu_attrs = kzalloc(len, GFP_KERNEL);
if (!tcmu_attrs) {
ret = -ENOMEM;
goto out_unreg_genl;
}
for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
tcmu_attrs[i] = passthrough_attrib_attrs[i];
}
tcmu_attrs[i] = &tcmu_attr_cmd_time_out;
tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
ret = transport_backend_register(&tcmu_ops);
if (ret)
goto out_attrs;
return 0;
out_attrs:
kfree(tcmu_attrs);
out_unreg_genl:
genl_unregister_family(&tcmu_genl_family);
out_unreg_device:
root_device_unregister(tcmu_root_device);
out_free_cache:
kmem_cache_destroy(tcmu_cmd_cache);
return ret;
}
static void __exit tcmu_module_exit(void)
{
target_backend_unregister(&tcmu_ops);
kfree(tcmu_attrs);
genl_unregister_family(&tcmu_genl_family);
root_device_unregister(tcmu_root_device);
kmem_cache_destroy(tcmu_cmd_cache);
}
MODULE_DESCRIPTION("TCM USER subsystem plugin");
MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
MODULE_LICENSE("GPL");
module_init(tcmu_module_init);
module_exit(tcmu_module_exit);