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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/drivers/target/target_core_user.c

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51 KiB
C
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/*
* 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 <linux/mutex.h>
#include <linux/kthread.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 8MB */
#define CMDR_SIZE (8 * 1024 * 1024)
/*
* For data area, the block size is PAGE_SIZE and
* the total size is 256K * PAGE_SIZE.
*/
#define DATA_BLOCK_SIZE PAGE_SIZE
#define DATA_BLOCK_BITS (256 * 1024)
#define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
#define DATA_BLOCK_INIT_BITS 128
/* The total size of the ring is 8M + 256K * PAGE_SIZE */
#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
/* Default maximum of the global data blocks(512K * PAGE_SIZE) */
#define TCMU_GLOBAL_MAX_BLOCKS (512 * 1024)
static u8 tcmu_kern_cmd_reply_supported;
static struct device *tcmu_root_device;
struct tcmu_hba {
u32 host_id;
};
#define TCMU_CONFIG_LEN 256
struct tcmu_nl_cmd {
/* wake up thread waiting for reply */
struct completion complete;
int cmd;
int status;
};
struct tcmu_dev {
struct list_head node;
struct kref kref;
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 inode *inode;
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;
struct mutex cmdr_lock;
bool waiting_global;
uint32_t dbi_max;
uint32_t dbi_thresh;
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;
spinlock_t nl_cmd_lock;
struct tcmu_nl_cmd curr_nl_cmd;
/* wake up threads waiting on curr_nl_cmd */
wait_queue_head_t nl_cmd_wq;
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 task_struct *unmap_thread;
static wait_queue_head_t unmap_wait;
static DEFINE_MUTEX(root_udev_mutex);
static LIST_HEAD(root_udev);
static atomic_t global_db_count = ATOMIC_INIT(0);
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", },
};
static struct nla_policy tcmu_attr_policy[TCMU_ATTR_MAX+1] = {
[TCMU_ATTR_DEVICE] = { .type = NLA_STRING },
[TCMU_ATTR_MINOR] = { .type = NLA_U32 },
[TCMU_ATTR_CMD_STATUS] = { .type = NLA_S32 },
[TCMU_ATTR_DEVICE_ID] = { .type = NLA_U32 },
[TCMU_ATTR_SUPP_KERN_CMD_REPLY] = { .type = NLA_U8 },
};
static int tcmu_genl_cmd_done(struct genl_info *info, int completed_cmd)
{
struct se_device *dev;
struct tcmu_dev *udev;
struct tcmu_nl_cmd *nl_cmd;
int dev_id, rc, ret = 0;
bool is_removed = (completed_cmd == TCMU_CMD_REMOVED_DEVICE);
if (!info->attrs[TCMU_ATTR_CMD_STATUS] ||
!info->attrs[TCMU_ATTR_DEVICE_ID]) {
printk(KERN_ERR "TCMU_ATTR_CMD_STATUS or TCMU_ATTR_DEVICE_ID not set, doing nothing\n");
return -EINVAL;
}
dev_id = nla_get_u32(info->attrs[TCMU_ATTR_DEVICE_ID]);
rc = nla_get_s32(info->attrs[TCMU_ATTR_CMD_STATUS]);
dev = target_find_device(dev_id, !is_removed);
if (!dev) {
printk(KERN_ERR "tcmu nl cmd %u/%u completion could not find device with dev id %u.\n",
completed_cmd, rc, dev_id);
return -ENODEV;
}
udev = TCMU_DEV(dev);
spin_lock(&udev->nl_cmd_lock);
nl_cmd = &udev->curr_nl_cmd;
pr_debug("genl cmd done got id %d curr %d done %d rc %d\n", dev_id,
nl_cmd->cmd, completed_cmd, rc);
if (nl_cmd->cmd != completed_cmd) {
printk(KERN_ERR "Mismatched commands (Expecting reply for %d. Current %d).\n",
completed_cmd, nl_cmd->cmd);
ret = -EINVAL;
} else {
nl_cmd->status = rc;
}
spin_unlock(&udev->nl_cmd_lock);
if (!is_removed)
target_undepend_item(&dev->dev_group.cg_item);
if (!ret)
complete(&nl_cmd->complete);
return ret;
}
static int tcmu_genl_rm_dev_done(struct sk_buff *skb, struct genl_info *info)
{
return tcmu_genl_cmd_done(info, TCMU_CMD_REMOVED_DEVICE);
}
static int tcmu_genl_add_dev_done(struct sk_buff *skb, struct genl_info *info)
{
return tcmu_genl_cmd_done(info, TCMU_CMD_ADDED_DEVICE);
}
static int tcmu_genl_reconfig_dev_done(struct sk_buff *skb,
struct genl_info *info)
{
return tcmu_genl_cmd_done(info, TCMU_CMD_RECONFIG_DEVICE);
}
static int tcmu_genl_set_features(struct sk_buff *skb, struct genl_info *info)
{
if (info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]) {
tcmu_kern_cmd_reply_supported =
nla_get_u8(info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]);
printk(KERN_INFO "tcmu daemon: command reply support %u.\n",
tcmu_kern_cmd_reply_supported);
}
return 0;
}
static const struct genl_ops tcmu_genl_ops[] = {
{
.cmd = TCMU_CMD_SET_FEATURES,
.flags = GENL_ADMIN_PERM,
.policy = tcmu_attr_policy,
.doit = tcmu_genl_set_features,
},
{
.cmd = TCMU_CMD_ADDED_DEVICE_DONE,
.flags = GENL_ADMIN_PERM,
.policy = tcmu_attr_policy,
.doit = tcmu_genl_add_dev_done,
},
{
.cmd = TCMU_CMD_REMOVED_DEVICE_DONE,
.flags = GENL_ADMIN_PERM,
.policy = tcmu_attr_policy,
.doit = tcmu_genl_rm_dev_done,
},
{
.cmd = TCMU_CMD_RECONFIG_DEVICE_DONE,
.flags = GENL_ADMIN_PERM,
.policy = tcmu_attr_policy,
.doit = tcmu_genl_reconfig_dev_done,
},
};
/* Our generic netlink family */
static struct genl_family tcmu_genl_family __ro_after_init = {
.module = THIS_MODULE,
.hdrsize = 0,
.name = "TCM-USER",
.version = 2,
.maxattr = TCMU_ATTR_MAX,
.mcgrps = tcmu_mcgrps,
.n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
.netnsok = true,
.ops = tcmu_genl_ops,
.n_ops = ARRAY_SIZE(tcmu_genl_ops),
};
#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, uint32_t len)
{
struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
uint32_t i;
for (i = 0; i < len; i++)
clear_bit(tcmu_cmd->dbi[i], udev->data_bitmap);
}
static inline bool tcmu_get_empty_block(struct tcmu_dev *udev,
struct tcmu_cmd *tcmu_cmd)
{
struct page *page;
int ret, dbi;
dbi = find_first_zero_bit(udev->data_bitmap, udev->dbi_thresh);
if (dbi == udev->dbi_thresh)
return false;
page = radix_tree_lookup(&udev->data_blocks, dbi);
if (!page) {
if (atomic_add_return(1, &global_db_count) >
TCMU_GLOBAL_MAX_BLOCKS) {
atomic_dec(&global_db_count);
return false;
}
/* try to get new page from the mm */
page = alloc_page(GFP_KERNEL);
if (!page)
goto err_alloc;
ret = radix_tree_insert(&udev->data_blocks, dbi, page);
if (ret)
goto err_insert;
}
if (dbi > udev->dbi_max)
udev->dbi_max = dbi;
set_bit(dbi, udev->data_bitmap);
tcmu_cmd_set_dbi(tcmu_cmd, dbi);
return true;
err_insert:
__free_page(page);
err_alloc:
atomic_dec(&global_db_count);
return false;
}
static bool tcmu_get_empty_blocks(struct tcmu_dev *udev,
struct tcmu_cmd *tcmu_cmd)
{
int i;
udev->waiting_global = false;
for (i = tcmu_cmd->dbi_cur; i < tcmu_cmd->dbi_cnt; i++) {
if (!tcmu_get_empty_block(udev, tcmu_cmd))
goto err;
}
return true;
err:
udev->waiting_global = true;
/* Try to wake up the unmap thread */
wake_up(&unmap_wait);
return false;
}
static inline struct page *
tcmu_get_block_page(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 iovec *iov)
{
return (size_t)iov->iov_base + iov->iov_len;
}
static int 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;
struct page *page;
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) {
if (to)
kunmap_atomic(to);
block_remaining = DATA_BLOCK_SIZE;
dbi = tcmu_cmd_get_dbi(tcmu_cmd);
page = tcmu_get_block_page(udev, dbi);
to = kmap_atomic(page);
}
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 += offset;
if (*iov_cnt != 0 &&
to_offset == iov_tail(*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);
}
if (to)
kunmap_atomic(to);
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 = NULL, *to;
size_t copy_bytes, offset;
struct scatterlist *sg, *data_sg;
struct page *page;
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) {
if (from)
kunmap_atomic(from);
block_remaining = DATA_BLOCK_SIZE;
dbi = tcmu_cmd_get_dbi(cmd);
page = tcmu_get_block_page(udev, dbi);
from = kmap_atomic(page);
}
copy_bytes = min_t(size_t, sg_remaining,
block_remaining);
offset = DATA_BLOCK_SIZE - block_remaining;
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);
}
if (from)
kunmap_atomic(from);
}
static inline size_t spc_bitmap_free(unsigned long *bitmap, uint32_t thresh)
{
return DATA_BLOCK_SIZE * (thresh - bitmap_weight(bitmap, thresh));
}
/*
* 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, struct tcmu_cmd *cmd,
size_t cmd_size, size_t data_needed)
{
struct tcmu_mailbox *mb = udev->mb_addr;
uint32_t blocks_needed = (data_needed + DATA_BLOCK_SIZE - 1)
/ DATA_BLOCK_SIZE;
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;
}
/* try to check and get the data blocks as needed */
space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh);
if (space < data_needed) {
unsigned long blocks_left = DATA_BLOCK_BITS - udev->dbi_thresh;
unsigned long grow;
if (blocks_left < blocks_needed) {
pr_debug("no data space: only %lu available, but ask for %zu\n",
blocks_left * DATA_BLOCK_SIZE,
data_needed);
return false;
}
/* Try to expand the thresh */
if (!udev->dbi_thresh) {
/* From idle state */
uint32_t init_thresh = DATA_BLOCK_INIT_BITS;
udev->dbi_thresh = max(blocks_needed, init_thresh);
} else {
/*
* Grow the data area by max(blocks needed,
* dbi_thresh / 2), but limited to the max
* DATA_BLOCK_BITS size.
*/
grow = max(blocks_needed, udev->dbi_thresh / 2);
udev->dbi_thresh += grow;
if (udev->dbi_thresh > DATA_BLOCK_BITS)
udev->dbi_thresh = DATA_BLOCK_BITS;
}
}
return tcmu_get_empty_blocks(udev, cmd);
}
static inline size_t tcmu_cmd_get_base_cmd_size(size_t iov_cnt)
{
return max(offsetof(struct tcmu_cmd_entry, req.iov[iov_cnt]),
sizeof(struct tcmu_cmd_entry));
}
static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd *tcmu_cmd,
size_t base_command_size)
{
struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
size_t command_size;
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));
return command_size;
}
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 as many iovs as possbile for potential uses here,
* because it's expensive to tell how many regions are freed in
* the bitmap & global data pool, as the size calculated here
* will only be used to do the checks.
*
* The size will be recalculated later as actually needed to save
* cmd area memories.
*/
base_command_size = tcmu_cmd_get_base_cmd_size(tcmu_cmd->dbi_cnt);
command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
mutex_lock(&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);
mutex_unlock(&udev->cmdr_lock);
return TCM_INVALID_CDB_FIELD;
}
while (!is_ring_space_avail(udev, tcmu_cmd, 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");
mutex_unlock(&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;
}
mutex_lock(&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_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;
tcmu_flush_dcache_range(entry, sizeof(*entry));
UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
tcmu_flush_dcache_range(mb, sizeof(*mb));
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
WARN_ON(cmd_head != 0);
}
entry = (void *) mb + CMDR_OFF + cmd_head;
memset(entry, 0, command_size);
tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
entry->hdr.cmd_id = tcmu_cmd->cmd_id;
/* Handle allocating space from the data area */
tcmu_cmd_reset_dbi_cur(tcmu_cmd);
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 = 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) {
tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
mutex_unlock(&udev->cmdr_lock);
pr_err("tcmu: alloc and scatter data failed\n");
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
entry->req.iov_cnt = iov_cnt;
/* Handle BIDI commands */
iov_cnt = 0;
if (se_cmd->se_cmd_flags & SCF_BIDI) {
iov++;
ret = scatter_data_area(udev, tcmu_cmd,
se_cmd->t_bidi_data_sg,
se_cmd->t_bidi_data_nents,
&iov, &iov_cnt, false);
if (ret) {
tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
mutex_unlock(&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;
/*
* Recalaulate the command's base size and size according
* to the actual needs
*/
base_command_size = tcmu_cmd_get_base_cmd_size(entry->req.iov_cnt +
entry->req.iov_bidi_cnt);
command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
/* 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));
mutex_unlock(&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) {
transport_copy_sense_to_cmd(se_cmd, entry->rsp.sense_buffer);
} 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, cmd->dbi_cnt);
tcmu_free_cmd(cmd);
}
static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
{
struct tcmu_mailbox *mb;
int handled = 0;
if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
pr_err("ring broken, not handling completions\n");
return 0;
}
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 */
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;
spin_lock_irqsave(&udev->commands_lock, flags);
idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
spin_unlock_irqrestore(&udev->commands_lock, flags);
/* Try to wake up the ummap thread */
wake_up(&unmap_wait);
/*
* 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;
kref_init(&udev->kref);
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);
mutex_init(&udev->cmdr_lock);
idr_init(&udev->commands);
spin_lock_init(&udev->commands_lock);
setup_timer(&udev->timeout, tcmu_device_timedout,
(unsigned long)udev);
init_waitqueue_head(&udev->nl_cmd_wq);
spin_lock_init(&udev->nl_cmd_lock);
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);
mutex_lock(&tcmu_dev->cmdr_lock);
tcmu_handle_completions(tcmu_dev);
mutex_unlock(&tcmu_dev->cmdr_lock);
return 0;
}
/*
* 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 struct page *tcmu_try_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
{
struct page *page;
int ret;
mutex_lock(&udev->cmdr_lock);
page = tcmu_get_block_page(udev, dbi);
if (likely(page)) {
mutex_unlock(&udev->cmdr_lock);
return page;
}
/*
* Normally it shouldn't be here:
* Only when the userspace has touched the blocks which
* are out of the tcmu_cmd's data iov[], and will return
* one zeroed page.
*/
pr_warn("Block(%u) out of cmd's iov[] has been touched!\n", dbi);
pr_warn("Mostly it will be a bug of userspace, please have a check!\n");
if (dbi >= udev->dbi_thresh) {
/* Extern the udev->dbi_thresh to dbi + 1 */
udev->dbi_thresh = dbi + 1;
udev->dbi_max = dbi;
}
page = radix_tree_lookup(&udev->data_blocks, dbi);
if (!page) {
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page) {
mutex_unlock(&udev->cmdr_lock);
return NULL;
}
ret = radix_tree_insert(&udev->data_blocks, dbi, page);
if (ret) {
mutex_unlock(&udev->cmdr_lock);
__free_page(page);
return NULL;
}
/*
* Since this case is rare in page fault routine, here we
* will allow the global_db_count >= TCMU_GLOBAL_MAX_BLOCKS
* to reduce possible page fault call trace.
*/
atomic_inc(&global_db_count);
}
mutex_unlock(&udev->cmdr_lock);
return page;
}
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 {
uint32_t dbi;
/* For the dynamically growing data area pages */
dbi = (offset - udev->data_off) / DATA_BLOCK_SIZE;
page = tcmu_try_get_block_page(udev, dbi);
if (!page)
return VM_FAULT_NOPAGE;
}
get_page(page);
vmf->page = page;
return 0;
}
static const struct vm_operations_struct tcmu_vm_ops = {
.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;
udev->inode = inode;
kref_get(&udev->kref);
pr_debug("open\n");
return 0;
}
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->uio_info.name);
kfree(udev->name);
kfree(udev);
}
static void tcmu_dev_kref_release(struct kref *kref)
{
struct tcmu_dev *udev = container_of(kref, struct tcmu_dev, kref);
struct se_device *dev = &udev->se_dev;
call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
}
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");
/* release ref from open */
kref_put(&udev->kref, tcmu_dev_kref_release);
return 0;
}
static void tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
{
struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
if (!tcmu_kern_cmd_reply_supported)
return;
relock:
spin_lock(&udev->nl_cmd_lock);
if (nl_cmd->cmd != TCMU_CMD_UNSPEC) {
spin_unlock(&udev->nl_cmd_lock);
pr_debug("sleeping for open nl cmd\n");
wait_event(udev->nl_cmd_wq, (nl_cmd->cmd == TCMU_CMD_UNSPEC));
goto relock;
}
memset(nl_cmd, 0, sizeof(*nl_cmd));
nl_cmd->cmd = cmd;
init_completion(&nl_cmd->complete);
spin_unlock(&udev->nl_cmd_lock);
}
static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev)
{
struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
int ret;
DEFINE_WAIT(__wait);
if (!tcmu_kern_cmd_reply_supported)
return 0;
pr_debug("sleeping for nl reply\n");
wait_for_completion(&nl_cmd->complete);
spin_lock(&udev->nl_cmd_lock);
nl_cmd->cmd = TCMU_CMD_UNSPEC;
ret = nl_cmd->status;
nl_cmd->status = 0;
spin_unlock(&udev->nl_cmd_lock);
wake_up_all(&udev->nl_cmd_wq);
return ret;;
}
static int tcmu_netlink_event(struct tcmu_dev *udev, enum tcmu_genl_cmd cmd,
int reconfig_attr, const void *reconfig_data)
{
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, udev->uio_info.name);
if (ret < 0)
goto free_skb;
ret = nla_put_u32(skb, TCMU_ATTR_MINOR, udev->uio_info.uio_dev->minor);
if (ret < 0)
goto free_skb;
ret = nla_put_u32(skb, TCMU_ATTR_DEVICE_ID, udev->se_dev.dev_index);
if (ret < 0)
goto free_skb;
if (cmd == TCMU_CMD_RECONFIG_DEVICE) {
switch (reconfig_attr) {
case TCMU_ATTR_DEV_CFG:
ret = nla_put_string(skb, reconfig_attr, reconfig_data);
break;
case TCMU_ATTR_DEV_SIZE:
ret = nla_put_u64_64bit(skb, reconfig_attr,
*((u64 *)reconfig_data),
TCMU_ATTR_PAD);
break;
case TCMU_ATTR_WRITECACHE:
ret = nla_put_u8(skb, reconfig_attr,
*((u8 *)reconfig_data));
break;
default:
BUG();
}
if (ret < 0)
goto free_skb;
}
genlmsg_end(skb, msg_header);
tcmu_init_genl_cmd_reply(udev, cmd);
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;
if (!ret)
ret = tcmu_wait_genl_cmd_reply(udev);
return ret;
free_skb:
nlmsg_free(skb);
return ret;
}
static int tcmu_update_uio_info(struct tcmu_dev *udev)
{
struct tcmu_hba *hba = udev->hba->hba_ptr;
struct uio_info *info;
size_t size, used;
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;
return 0;
}
static int tcmu_configure_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
struct uio_info *info;
struct tcmu_mailbox *mb;
int ret = 0;
ret = tcmu_update_uio_info(udev);
if (ret)
return ret;
info = &udev->uio_info;
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;
udev->dbi_thresh = 0; /* Default in Idle state */
udev->waiting_global = false;
/* 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_KERNEL);
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;
if (!dev->dev_attrib.emulate_write_cache)
dev->dev_attrib.emulate_write_cache = 0;
dev->dev_attrib.hw_queue_depth = 128;
/*
* Get a ref incase userspace does a close on the uio device before
* LIO has initiated tcmu_free_device.
*/
kref_get(&udev->kref);
ret = tcmu_netlink_event(udev, TCMU_CMD_ADDED_DEVICE, 0, NULL);
if (ret)
goto err_netlink;
mutex_lock(&root_udev_mutex);
list_add(&udev->node, &root_udev);
mutex_unlock(&root_udev_mutex);
return 0;
err_netlink:
kref_put(&udev->kref, tcmu_dev_kref_release);
uio_unregister_device(&udev->uio_info);
err_register:
vfree(udev->mb_addr);
err_vzalloc:
kfree(info->name);
info->name = NULL;
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 bool tcmu_dev_configured(struct tcmu_dev *udev)
{
return udev->uio_info.uio_dev ? true : false;
}
static void tcmu_blocks_release(struct tcmu_dev *udev)
{
int i;
struct page *page;
/* Try to release all block pages */
mutex_lock(&udev->cmdr_lock);
for (i = 0; i <= udev->dbi_max; i++) {
page = radix_tree_delete(&udev->data_blocks, i);
if (page) {
__free_page(page);
atomic_dec(&global_db_count);
}
}
mutex_unlock(&udev->cmdr_lock);
}
static void tcmu_free_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
/* release ref from init */
kref_put(&udev->kref, tcmu_dev_kref_release);
}
static void tcmu_destroy_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);
mutex_lock(&root_udev_mutex);
list_del(&udev->node);
mutex_unlock(&root_udev_mutex);
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);
tcmu_netlink_event(udev, TCMU_CMD_REMOVED_DEVICE, 0, NULL);
uio_unregister_device(&udev->uio_info);
/* release ref from configure */
kref_put(&udev->kref, tcmu_dev_kref_release);
}
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 ssize_t tcmu_dev_config_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 = TCMU_DEV(da->da_dev);
return snprintf(page, PAGE_SIZE, "%s\n", udev->dev_config);
}
static ssize_t tcmu_dev_config_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 = TCMU_DEV(da->da_dev);
int ret, len;
len = strlen(page);
if (!len || len > TCMU_CONFIG_LEN - 1)
return -EINVAL;
/* Check if device has been configured before */
if (tcmu_dev_configured(udev)) {
ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
TCMU_ATTR_DEV_CFG, page);
if (ret) {
pr_err("Unable to reconfigure device\n");
return ret;
}
strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
ret = tcmu_update_uio_info(udev);
if (ret)
return ret;
return count;
}
strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
return count;
}
CONFIGFS_ATTR(tcmu_, dev_config);
static ssize_t tcmu_dev_size_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 = TCMU_DEV(da->da_dev);
return snprintf(page, PAGE_SIZE, "%zu\n", udev->dev_size);
}
static ssize_t tcmu_dev_size_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 = TCMU_DEV(da->da_dev);
u64 val;
int ret;
ret = kstrtou64(page, 0, &val);
if (ret < 0)
return ret;
/* Check if device has been configured before */
if (tcmu_dev_configured(udev)) {
ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
TCMU_ATTR_DEV_SIZE, &val);
if (ret) {
pr_err("Unable to reconfigure device\n");
return ret;
}
}
udev->dev_size = val;
return count;
}
CONFIGFS_ATTR(tcmu_, dev_size);
static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
char *page)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
struct se_dev_attrib, da_group);
return snprintf(page, PAGE_SIZE, "%i\n", da->emulate_write_cache);
}
static ssize_t tcmu_emulate_write_cache_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 = TCMU_DEV(da->da_dev);
u8 val;
int ret;
ret = kstrtou8(page, 0, &val);
if (ret < 0)
return ret;
/* Check if device has been configured before */
if (tcmu_dev_configured(udev)) {
ret = tcmu_netlink_event(udev, TCMU_CMD_RECONFIG_DEVICE,
TCMU_ATTR_WRITECACHE, &val);
if (ret) {
pr_err("Unable to reconfigure device\n");
return ret;
}
}
da->emulate_write_cache = val;
return count;
}
CONFIGFS_ATTR(tcmu_, emulate_write_cache);
static struct configfs_attribute *tcmu_attrib_attrs[] = {
&tcmu_attr_cmd_time_out,
&tcmu_attr_dev_config,
&tcmu_attr_dev_size,
&tcmu_attr_emulate_write_cache,
NULL,
};
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,
.destroy_device = tcmu_destroy_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 unmap_thread_fn(void *data)
{
struct tcmu_dev *udev;
loff_t off;
uint32_t start, end, block;
struct page *page;
int i;
while (!kthread_should_stop()) {
DEFINE_WAIT(__wait);
prepare_to_wait(&unmap_wait, &__wait, TASK_INTERRUPTIBLE);
schedule();
finish_wait(&unmap_wait, &__wait);
if (kthread_should_stop())
break;
mutex_lock(&root_udev_mutex);
list_for_each_entry(udev, &root_udev, node) {
mutex_lock(&udev->cmdr_lock);
/* Try to complete the finished commands first */
tcmu_handle_completions(udev);
/* Skip the udevs waiting the global pool or in idle */
if (udev->waiting_global || !udev->dbi_thresh) {
mutex_unlock(&udev->cmdr_lock);
continue;
}
end = udev->dbi_max + 1;
block = find_last_bit(udev->data_bitmap, end);
if (block == udev->dbi_max) {
/*
* The last bit is dbi_max, so there is
* no need to shrink any blocks.
*/
mutex_unlock(&udev->cmdr_lock);
continue;
} else if (block == end) {
/* The current udev will goto idle state */
udev->dbi_thresh = start = 0;
udev->dbi_max = 0;
} else {
udev->dbi_thresh = start = block + 1;
udev->dbi_max = block;
}
/* Here will truncate the data area from off */
off = udev->data_off + start * DATA_BLOCK_SIZE;
unmap_mapping_range(udev->inode->i_mapping, off, 0, 1);
/* Release the block pages */
for (i = start; i < end; i++) {
page = radix_tree_delete(&udev->data_blocks, i);
if (page) {
__free_page(page);
atomic_dec(&global_db_count);
}
}
mutex_unlock(&udev->cmdr_lock);
}
/*
* Try to wake up the udevs who are waiting
* for the global data pool.
*/
list_for_each_entry(udev, &root_udev, node) {
if (udev->waiting_global)
wake_up(&udev->wait_cmdr);
}
mutex_unlock(&root_udev_mutex);
}
return 0;
}
static int __init tcmu_module_init(void)
{
int ret, i, k, 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 *);
}
for (i = 0; tcmu_attrib_attrs[i] != NULL; i++) {
len += sizeof(struct configfs_attribute *);
}
len += sizeof(struct configfs_attribute *);
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];
}
for (k = 0; tcmu_attrib_attrs[k] != NULL; k++) {
tcmu_attrs[i] = tcmu_attrib_attrs[k];
i++;
}
tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
ret = transport_backend_register(&tcmu_ops);
if (ret)
goto out_attrs;
init_waitqueue_head(&unmap_wait);
unmap_thread = kthread_run(unmap_thread_fn, NULL, "tcmu_unmap");
if (IS_ERR(unmap_thread)) {
ret = PTR_ERR(unmap_thread);
goto out_unreg_transport;
}
return 0;
out_unreg_transport:
target_backend_unregister(&tcmu_ops);
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)
{
kthread_stop(unmap_thread);
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);
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