target/user: Introduce data_bitmap, replace data_length/data_head/data_tail (26418649) · Commits · 戴 / test

drivers/target/target_core_user.c

+121 −100

Original line number	Diff line number	Diff line
		@@ -26,6 +26,7 @@
		#include <linux/vmalloc.h>
		#include <linux/uio_driver.h>
		#include <linux/stringify.h>
		#include <linux/bitops.h>
		#include <net/genetlink.h>
		#include <scsi/scsi_common.h>
		#include <scsi/scsi_proto.h>
		@@ -63,8 +64,11 @@

		#define TCMU_TIME_OUT (30 * MSEC_PER_SEC)

		#define DATA_BLOCK_BITS 256
		#define DATA_BLOCK_SIZE 4096

		#define CMDR_SIZE (16 * 4096)
		#define DATA_SIZE (257 * 4096)
		#define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)

		#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)

		@@ -93,12 +97,11 @@ struct tcmu_dev {
		u32 cmdr_size;
		u32 cmdr_last_cleaned;
		/* Offset of data ring from start of mb */
		/* Must add data_off and mb_addr to get the address */
		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;

		DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);

		wait_queue_head_t wait_cmdr;
		/* TODO should this be a mutex? */
		@@ -122,9 +125,9 @@ struct tcmu_cmd {

		uint16_t cmd_id;

		/* Can't use se_cmd->data_length when cleaning up expired cmds, because if
		/* Can't use se_cmd when cleaning up expired cmds, because if
		cmd has been completed then accessing se_cmd is off limits */
		size_t data_length;
		DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);

		unsigned long deadline;

		@@ -168,13 +171,6 @@ static struct tcmu_cmd tcmu_alloc_cmd(struct se_cmd se_cmd)

		tcmu_cmd->se_cmd = se_cmd;
		tcmu_cmd->tcmu_dev = udev;
		tcmu_cmd->data_length = se_cmd->data_length;

		if (se_cmd->se_cmd_flags & SCF_BIDI) {
		BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
		tcmu_cmd->data_length += se_cmd->t_bidi_data_sg->length;
		}

		tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);

		idr_preload(GFP_KERNEL);
		@@ -242,111 +238,115 @@ static inline void new_iov(struct iovec *iov, int iov_cnt,

		iovec = *iov;
		memset(iovec, 0, sizeof(struct iovec));

		/* Even iov_base is relative to mb_addr */
		iovec->iov_base = (void __user *) udev->data_off +
		udev->data_head;
		}

		#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(struct tcmu_dev *dev,
		int block, int remaining)
		{
		return dev->data_off + block * 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 void alloc_and_scatter_data_area(struct tcmu_dev *udev,
		struct scatterlist *data_sg, unsigned int data_nents,
		struct iovec *iov, int iov_cnt, bool copy_data)
		{
		int i;
		int i, block;
		int block_remaining = 0;
		void from, to;
		size_t copy_bytes;
		size_t copy_bytes, to_offset;
		struct scatterlist *sg;

		if (data_nents == 0)
		return;

		new_iov(iov, iov_cnt, udev);
		for_each_sg(data_sg, sg, data_nents, i) {
		copy_bytes = min_t(size_t, sg->length,
		head_to_end(udev->data_head, udev->data_size));
		int sg_remaining = sg->length;
		from = kmap_atomic(sg_page(sg)) + sg->offset;
		to = (void *) udev->mb_addr + udev->data_off + udev->data_head;

		if (copy_data) {
		memcpy(to, from, copy_bytes);
		tcmu_flush_dcache_range(to, copy_bytes);
		}

		while (sg_remaining > 0) {
		if (block_remaining == 0) {
		block = find_first_zero_bit(udev->data_bitmap,
		DATA_BLOCK_BITS);
		block_remaining = DATA_BLOCK_SIZE;
		set_bit(block, udev->data_bitmap);
		}
		copy_bytes = min_t(size_t, sg_remaining,
		block_remaining);
		to_offset = get_block_offset(udev, block,
		block_remaining);
		to = (void *)udev->mb_addr + to_offset;
		if (*iov_cnt != 0 &&
		to_offset == iov_tail(udev, *iov)) {
		(*iov)->iov_len += copy_bytes;

		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) {
		void *from_skip = from + copy_bytes;

		copy_bytes = sg->length - copy_bytes;

		} else {
		new_iov(iov, iov_cnt, udev);
		(iov)->iov_base = (void __user ) to_offset;
		(*iov)->iov_len = copy_bytes;

		}
		if (copy_data) {
		to = (void *) udev->mb_addr +
		udev->data_off + udev->data_head;
		memcpy(to, from_skip, copy_bytes);
		memcpy(to, from + sg->length - sg_remaining,
		copy_bytes);
		tcmu_flush_dcache_range(to, copy_bytes);
		}


		UPDATE_HEAD(udev->data_head,
		copy_bytes, udev->data_size);
		sg_remaining -= copy_bytes;
		block_remaining -= copy_bytes;
		}

		kunmap_atomic(from - sg->offset);
		}
		}

		static void free_data_area(struct tcmu_dev *udev, size_t length)
		static void free_data_area(struct tcmu_dev udev, struct tcmu_cmd cmd)
		{
		UPDATE_HEAD(udev->data_tail, length, udev->data_size);
		bitmap_xor(udev->data_bitmap, udev->data_bitmap, cmd->data_bitmap,
		DATA_BLOCK_BITS);
		}

		static void gather_and_free_data_area(struct tcmu_dev *udev,
		static void gather_data_area(struct tcmu_dev udev, unsigned long cmd_bitmap,
		struct scatterlist *data_sg, unsigned int data_nents)
		{
		int i;
		int i, block;
		int block_remaining = 0;
		void from, to;
		size_t copy_bytes;
		size_t copy_bytes, from_offset;
		struct scatterlist *sg;

		/* It'd be easier to look at entry's iovec again, but UAM */
		for_each_sg(data_sg, sg, data_nents, i) {
		copy_bytes = min_t(size_t, sg->length,
		head_to_end(udev->data_tail, udev->data_size));

		int sg_remaining = sg->length;
		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;
		while (sg_remaining > 0) {
		if (block_remaining == 0) {
		block = find_first_bit(cmd_bitmap,
		DATA_BLOCK_BITS);
		block_remaining = DATA_BLOCK_SIZE;
		clear_bit(block, cmd_bitmap);
		}
		copy_bytes = min_t(size_t, sg_remaining,
		block_remaining);
		from_offset = get_block_offset(udev, block,
		block_remaining);
		from = (void *) udev->mb_addr + from_offset;
		tcmu_flush_dcache_range(from, copy_bytes);
		memcpy(to, from, copy_bytes);

		free_data_area(udev, copy_bytes);

		/* Uh oh, wrapped the data buffer for this sg's data */
		if (sg->length != copy_bytes) {
		void *to_skip = to + copy_bytes;
		memcpy(to + sg->length - sg_remaining, from,
		copy_bytes);

		from = (void *) udev->mb_addr +
		udev->data_off + udev->data_tail;
		WARN_ON(udev->data_tail);
		copy_bytes = sg->length - copy_bytes;
		tcmu_flush_dcache_range(from, copy_bytes);
		memcpy(to_skip, from, copy_bytes);

		free_data_area(udev, copy_bytes);
		sg_remaining -= copy_bytes;
		block_remaining -= copy_bytes;
		}
		kunmap_atomic(to - sg->offset);
		}
		}

		static inline size_t spc_bitmap_free(unsigned long *bitmap)
		{
		return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
		bitmap_weight(bitmap, DATA_BLOCK_BITS));
		}

		/*
		* We can't queue a command until we have space available on the cmd ring and
		* space available on the data ring.
		@@ -380,10 +380,10 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t d
		return false;
		}

		space = spc_free(udev->data_head, udev->data_tail, udev->data_size);
		space = spc_bitmap_free(udev->data_bitmap);
		if (space < data_needed) {
		pr_debug("no data space: %zu %zu %zu\n", udev->data_head,
		udev->data_tail, udev->data_size);
		pr_debug("no data space: only %lu available, but ask for %lu\n",
		space, data_needed);
		return false;
		}

		@@ -402,6 +402,8 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
		uint32_t cmd_head;
		uint64_t cdb_off;
		bool copy_to_data_area;
		size_t data_length;
		DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);

		if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
		return -EINVAL;
		@@ -410,10 +412,12 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
		* Must be a certain minimum size for response sense info, but
		* also may be larger if the iov array is large.
		*
		* 3 iovs since we can describe the whole continuous are using one
		* for data, one for bidi and one more in the case of wrap.
		* We prepare way too many iovs for potential uses here, because it's
		* expensive to tell how many regions are freed in the bitmap
		*/
		base_command_size = max(offsetof(struct tcmu_cmd_entry, req.iov[3]),
		base_command_size = max(offsetof(struct tcmu_cmd_entry,
		req.iov[se_cmd->t_bidi_data_nents +
		se_cmd->t_data_nents]),
		sizeof(struct tcmu_cmd_entry));
		command_size = base_command_size
		+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
		@@ -424,13 +428,18 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)

		mb = udev->mb_addr;
		cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
		data_length = se_cmd->data_length;
		if (se_cmd->se_cmd_flags & SCF_BIDI) {
		BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
		data_length += se_cmd->t_bidi_data_sg->length;
		}
		if ((command_size > (udev->cmdr_size / 2))
		\|\| tcmu_cmd->data_length > (udev->data_size - 1))
		\|\| data_length > udev->data_size)
		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,
		"cmd/data ring buffers\n", command_size, data_length,
		udev->cmdr_size, udev->data_size);

		while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) {
		while (!is_ring_space_avail(udev, command_size, data_length)) {
		int ret;
		DEFINE_WAIT(__wait);

		@@ -477,6 +486,8 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
		entry->hdr.kflags = 0;
		entry->hdr.uflags = 0;

		bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS);

		/*
		* Fix up iovecs, and handle if allocation in data ring wrapped.
		*/
		@@ -495,6 +506,10 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
		se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false);
		entry->req.iov_bidi_cnt = iov_cnt;

		/* cmd's data_bitmap is what changed in process */
		bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
		DATA_BLOCK_BITS);

		/* 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));
		@@ -547,31 +562,36 @@ static void tcmu_handle_completion(struct tcmu_cmd cmd, struct tcmu_cmd_entry
		if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
		/* cmd has been completed already from timeout, just reclaim data
		ring space */
		free_data_area(udev, cmd->data_length);
		free_data_area(udev, cmd);
		return;
		}

		if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
		free_data_area(udev, cmd->data_length);
		free_data_area(udev, cmd);
		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);
		free_data_area(udev, cmd->data_length);
		free_data_area(udev, cmd);
		} else if (se_cmd->se_cmd_flags & SCF_BIDI) {
		/* Discard data_out buffer */
		free_data_area(udev, (size_t)se_cmd->t_data_sg->length);
		DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);

		/* Get Data-In buffer */
		gather_and_free_data_area(udev,
		/* Get Data-In buffer before clean up */
		bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
		gather_data_area(udev, bitmap,
		se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
		free_data_area(udev, cmd);
		} else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
		gather_and_free_data_area(udev,
		DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);

		bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
		gather_data_area(udev, bitmap,
		se_cmd->t_data_sg, se_cmd->t_data_nents);
		free_data_area(udev, cmd);
		} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
		free_data_area(udev, cmd->data_length);
		free_data_area(udev, cmd);
		} else if (se_cmd->data_direction != DMA_NONE) {
		pr_warn("TCMU: data direction was %d!\n",
		se_cmd->data_direction);
		@@ -912,6 +932,7 @@ static int tcmu_configure_device(struct se_device *dev)

		WARN_ON(!PAGE_ALIGNED(udev->data_off));
		WARN_ON(udev->data_size % PAGE_SIZE);
		WARN_ON(udev->data_size % DATA_BLOCK_SIZE);

		info->version = __stringify(TCMU_MAILBOX_VERSION);

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