diff --git a/Documentation/target/tcmu-design.txt b/Documentation/target/tcmu-design.txt index 5518465290bf..43e94ea6d2ca 100644 --- a/Documentation/target/tcmu-design.txt +++ b/Documentation/target/tcmu-design.txt @@ -138,27 +138,40 @@ signals the kernel via a 4-byte write(). When cmd_head equals cmd_tail, the ring is empty -- no commands are currently waiting to be processed by userspace. -TCMU commands start with a common header containing "len_op", a 32-bit -value that stores the length, as well as the opcode in the lowest -unused bits. Currently only two opcodes are defined, TCMU_OP_PAD and -TCMU_OP_CMD. When userspace encounters a command with PAD opcode, it -should skip ahead by the bytes in "length". (The kernel inserts PAD -entries to ensure each CMD entry fits contigously into the circular -buffer.) +TCMU commands are 8-byte aligned. They start with a common header +containing "len_op", a 32-bit value that stores the length, as well as +the opcode in the lowest unused bits. It also contains cmd_id and +flags fields for setting by the kernel (kflags) and userspace +(uflags). -When userspace handles a CMD, it finds the SCSI CDB (Command Data -Block) via tcmu_cmd_entry.req.cdb_off. This is an offset from the -start of the overall shared memory region, not the entry. The data -in/out buffers are accessible via tht req.iov[] array. Note that -each iov.iov_base is also an offset from the start of the region. +Currently only two opcodes are defined, TCMU_OP_CMD and TCMU_OP_PAD. -TCMU currently does not support BIDI operations. +When the opcode is CMD, the entry in the command ring is a struct +tcmu_cmd_entry. Userspace finds the SCSI CDB (Command Data Block) via +tcmu_cmd_entry.req.cdb_off. This is an offset from the start of the +overall shared memory region, not the entry. The data in/out buffers +are accessible via tht req.iov[] array. iov_cnt contains the number of +entries in iov[] needed to describe either the Data-In or Data-Out +buffers. For bidirectional commands, iov_cnt specifies how many iovec +entries cover the Data-Out area, and iov_bidi_count specifies how many +iovec entries immediately after that in iov[] cover the Data-In +area. Just like other fields, iov.iov_base is an offset from the start +of the region. When completing a command, userspace sets rsp.scsi_status, and rsp.sense_buffer if necessary. Userspace then increments mailbox.cmd_tail by entry.hdr.length (mod cmdr_size) and signals the kernel via the UIO method, a 4-byte write to the file descriptor. +When the opcode is PAD, userspace only updates cmd_tail as above -- +it's a no-op. (The kernel inserts PAD entries to ensure each CMD entry +is contiguous within the command ring.) + +More opcodes may be added in the future. If userspace encounters an +opcode it does not handle, it must set UNKNOWN_OP bit (bit 0) in +hdr.uflags, update cmd_tail, and proceed with processing additional +commands, if any. + The Data Area: This is shared-memory space after the command ring. The organization diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 1fbf304a9491..dbc872a6c981 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -344,8 +344,11 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) entry = (void *) mb + CMDR_OFF + cmd_head; tcmu_flush_dcache_range(entry, sizeof(*entry)); - tcmu_hdr_set_op(&entry->hdr, TCMU_OP_PAD); - tcmu_hdr_set_len(&entry->hdr, pad_size); + 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); @@ -355,9 +358,11 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) entry = (void *) mb + CMDR_OFF + cmd_head; tcmu_flush_dcache_range(entry, sizeof(*entry)); - tcmu_hdr_set_op(&entry->hdr, TCMU_OP_CMD); - tcmu_hdr_set_len(&entry->hdr, command_size); - entry->cmd_id = tcmu_cmd->cmd_id; + 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. @@ -407,6 +412,8 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) 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; @@ -464,6 +471,17 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry * 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); @@ -542,14 +560,16 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) tcmu_flush_dcache_range(entry, sizeof(*entry)); - if (tcmu_hdr_get_op(&entry->hdr) == TCMU_OP_PAD) { - UPDATE_HEAD(udev->cmdr_last_cleaned, tcmu_hdr_get_len(&entry->hdr), udev->cmdr_size); + 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) != TCMU_OP_CMD); + WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD); spin_lock(&udev->commands_lock); - cmd = idr_find(&udev->commands, entry->cmd_id); + cmd = idr_find(&udev->commands, entry->hdr.cmd_id); if (cmd) idr_remove(&udev->commands, cmd->cmd_id); spin_unlock(&udev->commands_lock); @@ -562,7 +582,9 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) tcmu_handle_completion(cmd, entry); - UPDATE_HEAD(udev->cmdr_last_cleaned, tcmu_hdr_get_len(&entry->hdr), udev->cmdr_size); + UPDATE_HEAD(udev->cmdr_last_cleaned, + tcmu_hdr_get_len(entry->hdr.len_op), + udev->cmdr_size); handled++; } @@ -840,14 +862,14 @@ static int tcmu_configure_device(struct se_device *dev) udev->data_size = TCMU_RING_SIZE - CMDR_SIZE; mb = udev->mb_addr; - mb->version = 1; + 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 = "1"; + 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; diff --git a/include/uapi/linux/target_core_user.h b/include/uapi/linux/target_core_user.h index b483d1909d3e..b67f99d3c520 100644 --- a/include/uapi/linux/target_core_user.h +++ b/include/uapi/linux/target_core_user.h @@ -6,7 +6,7 @@ #include #include -#define TCMU_VERSION "1.0" +#define TCMU_VERSION "2.0" /* * Ring Design @@ -39,9 +39,13 @@ * should process the next packet the same way, and so on. */ -#define TCMU_MAILBOX_VERSION 1 +#define TCMU_MAILBOX_VERSION 2 #define ALIGN_SIZE 64 /* Should be enough for most CPUs */ +/* See https://gcc.gnu.org/onlinedocs/cpp/Stringification.html */ +#define xstr(s) str(s) +#define str(s) #s + struct tcmu_mailbox { __u16 version; __u16 flags; @@ -64,31 +68,36 @@ enum tcmu_opcode { * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode. */ struct tcmu_cmd_entry_hdr { - __u32 len_op; + __u32 len_op; + __u16 cmd_id; + __u8 kflags; +#define TCMU_UFLAG_UNKNOWN_OP 0x1 + __u8 uflags; + } __packed; #define TCMU_OP_MASK 0x7 -static inline enum tcmu_opcode tcmu_hdr_get_op(struct tcmu_cmd_entry_hdr *hdr) +static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op) { - return hdr->len_op & TCMU_OP_MASK; + return len_op & TCMU_OP_MASK; } -static inline void tcmu_hdr_set_op(struct tcmu_cmd_entry_hdr *hdr, enum tcmu_opcode op) +static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op) { - hdr->len_op &= ~TCMU_OP_MASK; - hdr->len_op |= (op & TCMU_OP_MASK); + *len_op &= ~TCMU_OP_MASK; + *len_op |= (op & TCMU_OP_MASK); } -static inline __u32 tcmu_hdr_get_len(struct tcmu_cmd_entry_hdr *hdr) +static inline __u32 tcmu_hdr_get_len(__u32 len_op) { - return hdr->len_op & ~TCMU_OP_MASK; + return len_op & ~TCMU_OP_MASK; } -static inline void tcmu_hdr_set_len(struct tcmu_cmd_entry_hdr *hdr, __u32 len) +static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len) { - hdr->len_op &= TCMU_OP_MASK; - hdr->len_op |= len; + *len_op &= TCMU_OP_MASK; + *len_op |= len; } /* Currently the same as SCSI_SENSE_BUFFERSIZE */ @@ -97,13 +106,14 @@ static inline void tcmu_hdr_set_len(struct tcmu_cmd_entry_hdr *hdr, __u32 len) struct tcmu_cmd_entry { struct tcmu_cmd_entry_hdr hdr; - uint16_t cmd_id; - uint16_t __pad1; - union { struct { + uint32_t iov_cnt; + uint32_t iov_bidi_cnt; + uint32_t iov_dif_cnt; uint64_t cdb_off; - uint64_t iov_cnt; + uint64_t __pad1; + uint64_t __pad2; struct iovec iov[0]; } req; struct {