blob: a01093daf943ffe8ba5745e7f18000c343cdb71f [file] [log] [blame]
/*
* Copyright (C) 2013 Shaohua Li <shli@kernel.org>
* Copyright (C) 2014 Red Hat, 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/timer.h>
#include <linux/parser.h>
#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <linux/uio_driver.h>
#include <net/genetlink.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_backend.h>
#include <target/target_core_backend_configfs.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)
#define CMDR_SIZE (16 * 4096)
#define DATA_SIZE (257 * 4096)
#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 ring from start of mb */
size_t data_off;
size_t data_size;
/* Ring head + tail values. */
/* Must add data_off and mb_addr to get the address */
size_t data_head;
size_t data_tail;
wait_queue_head_t wait_cmdr;
/* TODO should this be a mutex? */
spinlock_t cmdr_lock;
struct idr commands;
spinlock_t commands_lock;
struct timer_list timeout;
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->data_length when cleaning up expired cmds, because if
cmd has been completed then accessing se_cmd is off limits */
size_t data_length;
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 = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = "TCM-USER",
.version = 1,
.maxattr = TCMU_ATTR_MAX,
.mcgrps = tcmu_mcgrps,
.n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
};
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;
tcmu_cmd->data_length = se_cmd->data_length;
tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
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) {
kmem_cache_free(tcmu_cmd_cache, 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 = (unsigned long) vaddr & ~PAGE_MASK;
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;
}
#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
/*
* We can't queue a command until we have space available on the cmd ring *and* space
* space avail on the data ring.
*
* 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;
u32 cmd_head;
size_t cmd_needed;
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_free(udev->data_head, udev->data_tail, udev->data_size);
if (space < data_needed) {
pr_debug("no data space: %zu %zu %zu\n", udev->data_head,
udev->data_tail, udev->data_size);
return false;
}
return true;
}
static int 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;
int i;
struct scatterlist *sg;
struct iovec *iov;
int iov_cnt = 0;
uint32_t cmd_head;
uint64_t cdb_off;
if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
return -EINVAL;
/*
* Must be a certain minimum size for response sense info, but
* also may be larger if the iov array is large.
*
* iovs = sgl_nents+1, for end-of-ring case, plus another 1
* b/c size == offsetof one-past-element.
*/
base_command_size = max(offsetof(struct tcmu_cmd_entry,
req.iov[se_cmd->t_data_nents + 2]),
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))
|| tcmu_cmd->data_length > (udev->data_size - 1))
pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu "
"cmd/data ring buffers\n", command_size, tcmu_cmd->data_length,
udev->cmdr_size, udev->data_size);
while (!is_ring_space_avail(udev, command_size, tcmu_cmd->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);
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 -ETIMEDOUT;
}
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;
/*
* Fix up iovecs, and handle if allocation in data ring wrapped.
*/
iov = &entry->req.iov[0];
for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
size_t copy_bytes = min((size_t)sg->length,
head_to_end(udev->data_head, udev->data_size));
void *from = kmap_atomic(sg_page(sg)) + sg->offset;
void *to = (void *) mb + udev->data_off + udev->data_head;
if (tcmu_cmd->se_cmd->data_direction == DMA_TO_DEVICE) {
memcpy(to, from, copy_bytes);
tcmu_flush_dcache_range(to, copy_bytes);
}
/* Even iov_base is relative to mb_addr */
iov->iov_len = copy_bytes;
iov->iov_base = (void __user *) udev->data_off +
udev->data_head;
iov_cnt++;
iov++;
UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
/* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */
if (sg->length != copy_bytes) {
from += copy_bytes;
copy_bytes = sg->length - copy_bytes;
iov->iov_len = copy_bytes;
iov->iov_base = (void __user *) udev->data_off +
udev->data_head;
if (se_cmd->data_direction == DMA_TO_DEVICE) {
to = (void *) mb + udev->data_off + udev->data_head;
memcpy(to, from, copy_bytes);
tcmu_flush_dcache_range(to, copy_bytes);
}
iov_cnt++;
iov++;
UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
}
kunmap_atomic(from);
}
entry->req.iov_cnt = iov_cnt;
entry->req.iov_bidi_cnt = 0;
entry->req.iov_dif_cnt = 0;
/* 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);
mod_timer(&udev->timeout,
round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT)));
return 0;
}
static int 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;
int ret;
tcmu_cmd = tcmu_alloc_cmd(se_cmd);
if (!tcmu_cmd)
return -ENOMEM;
ret = tcmu_queue_cmd_ring(tcmu_cmd);
if (ret < 0) {
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);
kmem_cache_free(tcmu_cmd_cache, 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;
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
/* cmd has been completed already from timeout, just reclaim data
ring space */
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
return;
}
if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
cmd->se_cmd);
transport_generic_request_failure(cmd->se_cmd,
TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
cmd->se_cmd = NULL;
kmem_cache_free(tcmu_cmd_cache, cmd);
return;
}
if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
se_cmd->scsi_sense_length);
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
}
else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
struct scatterlist *sg;
int i;
/* It'd be easier to look at entry's iovec again, but UAM */
for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
size_t copy_bytes;
void *to;
void *from;
copy_bytes = min((size_t)sg->length,
head_to_end(udev->data_tail, udev->data_size));
to = kmap_atomic(sg_page(sg)) + sg->offset;
WARN_ON(sg->length + sg->offset > PAGE_SIZE);
from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
tcmu_flush_dcache_range(from, copy_bytes);
memcpy(to, from, copy_bytes);
UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
/* Uh oh, wrapped the data buffer for this sg's data */
if (sg->length != copy_bytes) {
from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
WARN_ON(udev->data_tail);
to += copy_bytes;
copy_bytes = sg->length - copy_bytes;
tcmu_flush_dcache_range(from, copy_bytes);
memcpy(to, from, copy_bytes);
UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
}
kunmap_atomic(to);
}
} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
} else {
pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction);
}
target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
cmd->se_cmd = NULL;
kmem_cache_free(tcmu_cmd_cache, cmd);
}
static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
{
struct tcmu_mailbox *mb;
LIST_HEAD(cpl_cmds);
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_find(&udev->commands, entry->hdr.cmd_id);
if (cmd)
idr_remove(&udev->commands, cmd->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(cmd->deadline, jiffies))
return 0;
set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
cmd->se_cmd = NULL;
kmem_cache_free(tcmu_cmd_cache, cmd);
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;
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;
}
/*
* 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_area_struct *vma, struct vm_fault *vmf)
{
struct tcmu_dev *udev = 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(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;
addr = (void *)(unsigned long)info->mem[mi].addr + offset;
if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
page = virt_to_page(addr);
else
page = vmalloc_to_page(addr);
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;
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(&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(TCMU_RING_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 = TCMU_RING_SIZE - CMDR_SIZE;
mb = udev->mb_addr;
mb->version = TCMU_MAILBOX_VERSION;
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);
info->version = xstr(TCMU_MAILBOX_VERSION);
info->mem[0].name = "tcm-user command & data buffer";
info->mem[0].addr = (phys_addr_t) udev->mb_addr;
info->mem[0].size = TCMU_RING_SIZE;
info->mem[0].memtype = UIO_MEM_VIRTUAL;
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;
/* Other attributes can be configured in userspace */
dev->dev_attrib.hw_block_size = 512;
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_pending_cmd(int id, void *p, void *data)
{
struct tcmu_cmd *cmd = p;
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
return 0;
return -EINVAL;
}
static void tcmu_free_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
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);
i = idr_for_each(&udev->commands, tcmu_check_pending_cmd, NULL);
idr_destroy(&udev->commands);
spin_unlock_irq(&udev->commands_lock);
WARN_ON(i);
/* Device was configured */
if (udev->uio_info.uio_dev) {
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);
}
kfree(udev);
}
enum {
Opt_dev_config, Opt_dev_size, Opt_err,
};
static match_table_t tokens = {
{Opt_dev_config, "dev_config=%s"},
{Opt_dev_size, "dev_size=%u"},
{Opt_err, NULL}
};
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;
default:
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_execute_rw(struct se_cmd *se_cmd, struct scatterlist *sgl, u32 sgl_nents,
enum dma_data_direction data_direction)
{
int ret;
ret = tcmu_queue_cmd(se_cmd);
if (ret != 0)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
else
return TCM_NO_SENSE;
}
static sense_reason_t
tcmu_pass_op(struct se_cmd *se_cmd)
{
int ret = tcmu_queue_cmd(se_cmd);
if (ret != 0)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
else
return TCM_NO_SENSE;
}
static struct sbc_ops tcmu_sbc_ops = {
.execute_rw = tcmu_execute_rw,
.execute_sync_cache = tcmu_pass_op,
.execute_write_same = tcmu_pass_op,
.execute_write_same_unmap = tcmu_pass_op,
.execute_unmap = tcmu_pass_op,
};
static sense_reason_t
tcmu_parse_cdb(struct se_cmd *cmd)
{
sense_reason_t ret;
unsigned char *cdb = cmd->t_task_cdb;
switch (cdb[0]) {
case COMPARE_AND_WRITE:
case XDWRITEREAD_10:
pr_err("TCMU I/O mode does not support XDWRITEREAD10 or "
"COMPARE AND WRITE opcodes\n");
ret = TCM_UNSUPPORTED_SCSI_OPCODE;
break;
case VARIABLE_LENGTH_CMD:
if (get_unaligned_be16(&cdb[8]) == XDWRITEREAD_32) {
pr_err("TCMU I/O mode does not support XDWRITEREAD32\n");
ret = TCM_UNSUPPORTED_SCSI_OPCODE;
break;
}
/* fallthrough */
default:
ret = sbc_parse_cdb(cmd, &tcmu_sbc_ops);
}
return ret;
}
DEF_TB_DEFAULT_ATTRIBS(tcmu);
static struct configfs_attribute *tcmu_backend_dev_attrs[] = {
&tcmu_dev_attrib_emulate_model_alias.attr,
&tcmu_dev_attrib_emulate_dpo.attr,
&tcmu_dev_attrib_emulate_fua_write.attr,
&tcmu_dev_attrib_emulate_fua_read.attr,
&tcmu_dev_attrib_emulate_write_cache.attr,
&tcmu_dev_attrib_emulate_ua_intlck_ctrl.attr,
&tcmu_dev_attrib_emulate_tas.attr,
&tcmu_dev_attrib_emulate_tpu.attr,
&tcmu_dev_attrib_emulate_tpws.attr,
&tcmu_dev_attrib_emulate_caw.attr,
&tcmu_dev_attrib_emulate_3pc.attr,
&tcmu_dev_attrib_pi_prot_type.attr,
&tcmu_dev_attrib_hw_pi_prot_type.attr,
&tcmu_dev_attrib_pi_prot_format.attr,
&tcmu_dev_attrib_enforce_pr_isids.attr,
&tcmu_dev_attrib_is_nonrot.attr,
&tcmu_dev_attrib_emulate_rest_reord.attr,
&tcmu_dev_attrib_force_pr_aptpl.attr,
&tcmu_dev_attrib_hw_block_size.attr,
&tcmu_dev_attrib_block_size.attr,
&tcmu_dev_attrib_hw_max_sectors.attr,
&tcmu_dev_attrib_optimal_sectors.attr,
&tcmu_dev_attrib_hw_queue_depth.attr,
&tcmu_dev_attrib_queue_depth.attr,
&tcmu_dev_attrib_max_unmap_lba_count.attr,
&tcmu_dev_attrib_max_unmap_block_desc_count.attr,
&tcmu_dev_attrib_unmap_granularity.attr,
&tcmu_dev_attrib_unmap_granularity_alignment.attr,
&tcmu_dev_attrib_max_write_same_len.attr,
NULL,
};
static struct se_subsystem_api tcmu_template = {
.name = "user",
.inquiry_prod = "USER",
.inquiry_rev = TCMU_VERSION,
.owner = THIS_MODULE,
.transport_type = TRANSPORT_PLUGIN_VHBA_PDEV,
.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,
};
static int __init tcmu_module_init(void)
{
struct target_backend_cits *tbc = &tcmu_template.tb_cits;
int ret;
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;
}
target_core_setup_sub_cits(&tcmu_template);
tbc->tb_dev_attrib_cit.ct_attrs = tcmu_backend_dev_attrs;
ret = transport_subsystem_register(&tcmu_template);
if (ret)
goto out_unreg_genl;
return 0;
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)
{
transport_subsystem_release(&tcmu_template);
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);