--- /dev/null
+/*
+ * 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 <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_hw_block_size, 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_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;
+ unsigned long tmp_ul;
+
+ 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:
+ arg_p = match_strdup(&args[0]);
+ if (!arg_p) {
+ ret = -ENOMEM;
+ break;
+ }
+ ret = kstrtoul(arg_p, 0, &tmp_ul);
+ kfree(arg_p);
+ if (ret < 0) {
+ pr_err("kstrtoul() failed for hw_block_size=\n");
+ break;
+ }
+ if (!tmp_ul) {
+ pr_err("hw_block_size must be nonzero\n");
+ break;
+ }
+ dev->dev_attrib.hw_block_size = tmp_ul;
+ 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_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 sense_reason_t
+tcmu_parse_cdb(struct se_cmd *cmd)
+{
+ return passthrough_parse_cdb(cmd, tcmu_pass_op);
+}
+
+DEF_TB_DEV_ATTRIB_RO(tcmu, hw_pi_prot_type);
+TB_DEV_ATTR_RO(tcmu, hw_pi_prot_type);
+
+DEF_TB_DEV_ATTRIB_RO(tcmu, hw_block_size);
+TB_DEV_ATTR_RO(tcmu, hw_block_size);
+
+DEF_TB_DEV_ATTRIB_RO(tcmu, hw_max_sectors);
+TB_DEV_ATTR_RO(tcmu, hw_max_sectors);
+
+DEF_TB_DEV_ATTRIB_RO(tcmu, hw_queue_depth);
+TB_DEV_ATTR_RO(tcmu, hw_queue_depth);
+
+static struct configfs_attribute *tcmu_backend_dev_attrs[] = {
+ &tcmu_dev_attrib_hw_pi_prot_type.attr,
+ &tcmu_dev_attrib_hw_block_size.attr,
+ &tcmu_dev_attrib_hw_max_sectors.attr,
+ &tcmu_dev_attrib_hw_queue_depth.attr,
+ NULL,
+};
+
+static struct se_subsystem_api tcmu_template = {
+ .name = "user",
+ .inquiry_prod = "USER",
+ .inquiry_rev = TCMU_VERSION,
+ .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,
+};
+
+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);
Code Review / kvmfornfv.git / blobdiff