/* * Copyright (C) 2013 Shaohua Li * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * 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 struct device *tcmu_root_device; struct tcmu_hba { u32 host_id; }; #define TCMU_CONFIG_LEN 256 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; 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", }, }; /* Our generic netlink family */ static struct genl_family tcmu_genl_family __ro_after_init = { .module = THIS_MODULE, .hdrsize = 0, .name = "TCM-USER", .version = 1, .maxattr = TCMU_ATTR_MAX, .mcgrps = tcmu_mcgrps, .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps), .netnsok = true, }; #define tcmu_cmd_set_dbi_cur(cmd, index) ((cmd)->dbi_cur = (index)) #define tcmu_cmd_reset_dbi_cur(cmd) tcmu_cmd_set_dbi_cur(cmd, 0) #define tcmu_cmd_set_dbi(cmd, index) ((cmd)->dbi[(cmd)->dbi_cur++] = (index)) #define tcmu_cmd_get_dbi(cmd) ((cmd)->dbi[(cmd)->dbi_cur++]) static void tcmu_cmd_free_data(struct tcmu_cmd *tcmu_cmd, 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) return false; ret = radix_tree_insert(&udev->data_blocks, dbi, page); if (ret) { __free_page(page); return false; } } if (dbi > udev->dbi_max) udev->dbi_max = dbi; set_bit(dbi, udev->data_bitmap); tcmu_cmd_set_dbi(tcmu_cmd, dbi); return true; } 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 tcmu_dev *udev, 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 = (void *)(unsigned long)to + offset; if (*iov_cnt != 0 && to_offset == iov_tail(udev, *iov)) { (*iov)->iov_len += copy_bytes; } else { new_iov(iov, iov_cnt, udev); (*iov)->iov_base = (void __user *)to_offset; (*iov)->iov_len = copy_bytes; } if (copy_data) { memcpy(to, from + sg->length - sg_remaining, copy_bytes); tcmu_flush_dcache_range(to, copy_bytes); } sg_remaining -= copy_bytes; block_remaining -= copy_bytes; } kunmap_atomic(from - sg->offset); } 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 = (void *)(unsigned long)from + offset; tcmu_flush_dcache_range(from, copy_bytes); memcpy(to + sg->length - sg_remaining, from, copy_bytes); sg_remaining -= copy_bytes; block_remaining -= copy_bytes; } kunmap_atomic(to - sg->offset); } 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; } } if (!tcmu_get_empty_blocks(udev, cmd)) return false; return true; } 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_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); entry->hdr.cmd_id = tcmu_cmd->cmd_id; entry->hdr.kflags = 0; entry->hdr.uflags = 0; /* 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; entry->req.iov_dif_cnt = 0; /* Handle BIDI commands */ if (se_cmd->se_cmd_flags & SCF_BIDI) { iov_cnt = 0; 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) { memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer, se_cmd->scsi_sense_length); } else if (se_cmd->se_cmd_flags & SCF_BIDI) { /* Get Data-In buffer before clean up */ gather_data_area(udev, cmd, true); } else if (se_cmd->data_direction == DMA_FROM_DEVICE) { gather_data_area(udev, cmd, false); } else if (se_cmd->data_direction == DMA_TO_DEVICE) { /* TODO: */ } else if (se_cmd->data_direction != DMA_NONE) { pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction); } target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status); out: cmd->se_cmd = NULL; tcmu_cmd_free_data(cmd, 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); 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; 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 configure */ kref_put(&udev->kref, tcmu_dev_kref_release); return 0; } static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor) { struct sk_buff *skb; void *msg_header; int ret = -ENOMEM; skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); if (!skb) return ret; msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd); if (!msg_header) goto free_skb; ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name); if (ret < 0) goto free_skb; ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor); if (ret < 0) goto free_skb; genlmsg_end(skb, msg_header); ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0, TCMU_MCGRP_CONFIG, GFP_KERNEL); /* We don't care if no one is listening */ if (ret == -ESRCH) ret = 0; return ret; free_skb: nlmsg_free(skb); return ret; } static int tcmu_configure_device(struct se_device *dev) { struct tcmu_dev *udev = TCMU_DEV(dev); struct tcmu_hba *hba = udev->hba->hba_ptr; struct uio_info *info; struct tcmu_mailbox *mb; size_t size; size_t used; int ret = 0; char *str; info = &udev->uio_info; size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name, udev->dev_config); size += 1; /* for \0 */ str = kmalloc(size, GFP_KERNEL); if (!str) return -ENOMEM; used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name); if (udev->dev_config[0]) snprintf(str + used, size - used, "/%s", udev->dev_config); info->name = str; udev->mb_addr = vzalloc(CMDR_SIZE); if (!udev->mb_addr) { ret = -ENOMEM; goto err_vzalloc; } /* mailbox fits in first part of CMDR space */ udev->cmdr_size = CMDR_SIZE - CMDR_OFF; udev->data_off = CMDR_SIZE; udev->data_size = DATA_SIZE; 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(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name, udev->uio_info.uio_dev->minor); 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); 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); if (tcmu_dev_configured(udev)) { tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name, udev->uio_info.uio_dev->minor); uio_unregister_device(&udev->uio_info); } /* release ref from init */ 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_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); unsigned long val; int ret; ret = kstrtoul(page, 0, &val); if (ret < 0) return ret; udev->dev_size = val; /* Check if device has been configured before */ if (tcmu_dev_configured(udev)) { ret = tcmu_netlink_event(TCMU_CMD_RECONFIG_DEVICE, udev->uio_info.name, udev->uio_info.uio_dev->minor); if (ret) { pr_err("Unable to reconfigure device\n"); return ret; } } 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); int val; int ret; ret = kstrtouint(page, 0, &val); if (ret < 0) return ret; da->emulate_write_cache = val; /* Check if device has been configured before */ if (tcmu_dev_configured(udev)) { ret = tcmu_netlink_event(TCMU_CMD_RECONFIG_DEVICE, udev->uio_info.name, udev->uio_info.uio_dev->minor); if (ret) { pr_err("Unable to reconfigure device\n"); return ret; } } return count; } CONFIGFS_ATTR(tcmu_, emulate_write_cache); struct configfs_attribute *tcmu_attrib_attrs[] = { &tcmu_attr_cmd_time_out, &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, .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 (1) { 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 "); MODULE_AUTHOR("Andy Grover "); MODULE_LICENSE("GPL"); module_init(tcmu_module_init); module_exit(tcmu_module_exit);