target/user: Introduce data_bitmap, replace data_length/data_head/data_tail
The data_bitmap was introduced to support asynchornization accessing of data area. We divide mailbox data area into blocks, and use data_bitmap to track the usage of data area. All the new command's data would start with a new block, and may left unusable space after it end. But it's easy to track using data_bitmap. Now we can allocate data area for asynchronization accessing from userspace, since we can track the allocation using data_bitmap. The userspace part would be the same as Maxim's previous asynchronized implementation. Signed-off-by: Sheng Yang <sheng@yasker.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>hifive-unleashed-5.1
Sheng Yang
Nicholas Bellinger
parent
0c28481ffb
commit
26418649ee
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@ -26,6 +26,7 @@
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#include <linux/vmalloc.h>
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#include <linux/uio_driver.h>
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#include <linux/stringify.h>
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#include <linux/bitops.h>
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#include <net/genetlink.h>
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#include <scsi/scsi_common.h>
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#include <scsi/scsi_proto.h>
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@ -63,8 +64,11 @@
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#define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
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#define DATA_BLOCK_BITS 256
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#define DATA_BLOCK_SIZE 4096
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#define CMDR_SIZE (16 * 4096)
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#define DATA_SIZE (257 * 4096)
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#define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
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#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
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@ -93,12 +97,11 @@ struct tcmu_dev {
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u32 cmdr_size;
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u32 cmdr_last_cleaned;
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/* Offset of data ring from start of mb */
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/* Must add data_off and mb_addr to get the address */
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size_t data_off;
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size_t data_size;
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/* Ring head + tail values. */
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/* Must add data_off and mb_addr to get the address */
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size_t data_head;
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size_t data_tail;
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DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
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wait_queue_head_t wait_cmdr;
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/* TODO should this be a mutex? */
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@ -122,9 +125,9 @@ struct tcmu_cmd {
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uint16_t cmd_id;
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/* Can't use se_cmd->data_length when cleaning up expired cmds, because if
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/* Can't use se_cmd when cleaning up expired cmds, because if
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cmd has been completed then accessing se_cmd is off limits */
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size_t data_length;
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DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
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unsigned long deadline;
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@ -168,13 +171,6 @@ static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
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tcmu_cmd->se_cmd = se_cmd;
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tcmu_cmd->tcmu_dev = udev;
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tcmu_cmd->data_length = se_cmd->data_length;
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if (se_cmd->se_cmd_flags & SCF_BIDI) {
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BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
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tcmu_cmd->data_length += se_cmd->t_bidi_data_sg->length;
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}
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tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
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idr_preload(GFP_KERNEL);
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@ -242,111 +238,115 @@ static inline void new_iov(struct iovec **iov, int *iov_cnt,
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iovec = *iov;
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memset(iovec, 0, sizeof(struct iovec));
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/* Even iov_base is relative to mb_addr */
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iovec->iov_base = (void __user *) udev->data_off +
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udev->data_head;
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}
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#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
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/* offset is relative to mb_addr */
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static inline size_t get_block_offset(struct tcmu_dev *dev,
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int block, int remaining)
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{
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return dev->data_off + block * DATA_BLOCK_SIZE +
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DATA_BLOCK_SIZE - remaining;
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}
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static inline size_t iov_tail(struct tcmu_dev *udev, struct iovec *iov)
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{
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return (size_t)iov->iov_base + iov->iov_len;
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}
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static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
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struct scatterlist *data_sg, unsigned int data_nents,
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struct iovec **iov, int *iov_cnt, bool copy_data)
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{
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int i;
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int i, block;
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int block_remaining = 0;
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void *from, *to;
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size_t copy_bytes;
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size_t copy_bytes, to_offset;
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struct scatterlist *sg;
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if (data_nents == 0)
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return;
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new_iov(iov, iov_cnt, udev);
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for_each_sg(data_sg, sg, data_nents, i) {
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copy_bytes = min_t(size_t, sg->length,
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head_to_end(udev->data_head, udev->data_size));
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int sg_remaining = sg->length;
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from = kmap_atomic(sg_page(sg)) + sg->offset;
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to = (void *) udev->mb_addr + udev->data_off + udev->data_head;
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if (copy_data) {
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memcpy(to, from, copy_bytes);
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tcmu_flush_dcache_range(to, copy_bytes);
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}
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(*iov)->iov_len += copy_bytes;
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UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
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/* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */
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if (sg->length != copy_bytes) {
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void *from_skip = from + copy_bytes;
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copy_bytes = sg->length - copy_bytes;
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new_iov(iov, iov_cnt, udev);
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(*iov)->iov_len = copy_bytes;
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while (sg_remaining > 0) {
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if (block_remaining == 0) {
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block = find_first_zero_bit(udev->data_bitmap,
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DATA_BLOCK_BITS);
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block_remaining = DATA_BLOCK_SIZE;
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set_bit(block, udev->data_bitmap);
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}
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copy_bytes = min_t(size_t, sg_remaining,
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block_remaining);
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to_offset = get_block_offset(udev, block,
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block_remaining);
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to = (void *)udev->mb_addr + to_offset;
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if (*iov_cnt != 0 &&
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to_offset == iov_tail(udev, *iov)) {
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(*iov)->iov_len += copy_bytes;
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} else {
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new_iov(iov, iov_cnt, udev);
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(*iov)->iov_base = (void __user *) to_offset;
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(*iov)->iov_len = copy_bytes;
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}
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if (copy_data) {
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to = (void *) udev->mb_addr +
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udev->data_off + udev->data_head;
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memcpy(to, from_skip, copy_bytes);
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memcpy(to, from + sg->length - sg_remaining,
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copy_bytes);
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tcmu_flush_dcache_range(to, copy_bytes);
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}
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UPDATE_HEAD(udev->data_head,
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copy_bytes, udev->data_size);
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sg_remaining -= copy_bytes;
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block_remaining -= copy_bytes;
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}
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kunmap_atomic(from - sg->offset);
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}
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}
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static void free_data_area(struct tcmu_dev *udev, size_t length)
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static void free_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd)
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{
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UPDATE_HEAD(udev->data_tail, length, udev->data_size);
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bitmap_xor(udev->data_bitmap, udev->data_bitmap, cmd->data_bitmap,
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DATA_BLOCK_BITS);
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}
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static void gather_and_free_data_area(struct tcmu_dev *udev,
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struct scatterlist *data_sg, unsigned int data_nents)
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static void gather_data_area(struct tcmu_dev *udev, unsigned long *cmd_bitmap,
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struct scatterlist *data_sg, unsigned int data_nents)
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{
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int i;
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int i, block;
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int block_remaining = 0;
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void *from, *to;
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size_t copy_bytes;
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size_t copy_bytes, from_offset;
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struct scatterlist *sg;
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/* It'd be easier to look at entry's iovec again, but UAM */
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for_each_sg(data_sg, sg, data_nents, i) {
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copy_bytes = min_t(size_t, sg->length,
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head_to_end(udev->data_tail, udev->data_size));
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int sg_remaining = sg->length;
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to = kmap_atomic(sg_page(sg)) + sg->offset;
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WARN_ON(sg->length + sg->offset > PAGE_SIZE);
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from = (void *) udev->mb_addr +
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udev->data_off + udev->data_tail;
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tcmu_flush_dcache_range(from, copy_bytes);
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memcpy(to, from, copy_bytes);
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free_data_area(udev, copy_bytes);
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/* Uh oh, wrapped the data buffer for this sg's data */
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if (sg->length != copy_bytes) {
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void *to_skip = to + copy_bytes;
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from = (void *) udev->mb_addr +
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udev->data_off + udev->data_tail;
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WARN_ON(udev->data_tail);
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copy_bytes = sg->length - copy_bytes;
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while (sg_remaining > 0) {
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if (block_remaining == 0) {
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block = find_first_bit(cmd_bitmap,
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DATA_BLOCK_BITS);
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block_remaining = DATA_BLOCK_SIZE;
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clear_bit(block, cmd_bitmap);
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}
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copy_bytes = min_t(size_t, sg_remaining,
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block_remaining);
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from_offset = get_block_offset(udev, block,
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block_remaining);
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from = (void *) udev->mb_addr + from_offset;
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tcmu_flush_dcache_range(from, copy_bytes);
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memcpy(to_skip, from, copy_bytes);
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memcpy(to + sg->length - sg_remaining, from,
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copy_bytes);
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free_data_area(udev, copy_bytes);
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sg_remaining -= copy_bytes;
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block_remaining -= copy_bytes;
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}
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kunmap_atomic(to - sg->offset);
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}
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}
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static inline size_t spc_bitmap_free(unsigned long *bitmap)
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{
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return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
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bitmap_weight(bitmap, DATA_BLOCK_BITS));
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}
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/*
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* We can't queue a command until we have space available on the cmd ring *and*
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* space available on the data ring.
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@ -380,10 +380,10 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t d
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return false;
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}
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space = spc_free(udev->data_head, udev->data_tail, udev->data_size);
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space = spc_bitmap_free(udev->data_bitmap);
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if (space < data_needed) {
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pr_debug("no data space: %zu %zu %zu\n", udev->data_head,
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udev->data_tail, udev->data_size);
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pr_debug("no data space: only %lu available, but ask for %lu\n",
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space, data_needed);
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return false;
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}
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@ -402,6 +402,8 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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uint32_t cmd_head;
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uint64_t cdb_off;
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bool copy_to_data_area;
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size_t data_length;
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DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);
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if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
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return -EINVAL;
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@ -410,10 +412,12 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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* Must be a certain minimum size for response sense info, but
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* also may be larger if the iov array is large.
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*
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* 3 iovs since we can describe the whole continuous are using one
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* for data, one for bidi and one more in the case of wrap.
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* We prepare way too many iovs for potential uses here, because it's
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* expensive to tell how many regions are freed in the bitmap
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*/
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base_command_size = max(offsetof(struct tcmu_cmd_entry, req.iov[3]),
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base_command_size = max(offsetof(struct tcmu_cmd_entry,
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req.iov[se_cmd->t_bidi_data_nents +
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se_cmd->t_data_nents]),
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sizeof(struct tcmu_cmd_entry));
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command_size = base_command_size
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+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
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@ -424,13 +428,18 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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mb = udev->mb_addr;
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cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
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data_length = se_cmd->data_length;
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if (se_cmd->se_cmd_flags & SCF_BIDI) {
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BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
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data_length += se_cmd->t_bidi_data_sg->length;
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}
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if ((command_size > (udev->cmdr_size / 2))
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|| tcmu_cmd->data_length > (udev->data_size - 1))
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|| data_length > udev->data_size)
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pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu "
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"cmd/data ring buffers\n", command_size, tcmu_cmd->data_length,
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"cmd/data ring buffers\n", command_size, data_length,
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udev->cmdr_size, udev->data_size);
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while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) {
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while (!is_ring_space_avail(udev, command_size, data_length)) {
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int ret;
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DEFINE_WAIT(__wait);
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@ -477,6 +486,8 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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entry->hdr.kflags = 0;
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entry->hdr.uflags = 0;
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bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS);
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/*
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* Fix up iovecs, and handle if allocation in data ring wrapped.
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*/
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@ -495,6 +506,10 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false);
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entry->req.iov_bidi_cnt = iov_cnt;
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/* cmd's data_bitmap is what changed in process */
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bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
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DATA_BLOCK_BITS);
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/* All offsets relative to mb_addr, not start of entry! */
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cdb_off = CMDR_OFF + cmd_head + base_command_size;
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memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
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@ -547,31 +562,36 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *
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if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
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/* cmd has been completed already from timeout, just reclaim data
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ring space */
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free_data_area(udev, cmd->data_length);
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free_data_area(udev, cmd);
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return;
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}
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if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
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free_data_area(udev, cmd->data_length);
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free_data_area(udev, cmd);
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pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
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cmd->se_cmd);
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entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
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} else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
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memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
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se_cmd->scsi_sense_length);
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free_data_area(udev, cmd->data_length);
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free_data_area(udev, cmd);
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} else if (se_cmd->se_cmd_flags & SCF_BIDI) {
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/* Discard data_out buffer */
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free_data_area(udev, (size_t)se_cmd->t_data_sg->length);
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DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
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/* Get Data-In buffer */
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gather_and_free_data_area(udev,
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/* Get Data-In buffer before clean up */
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bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
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gather_data_area(udev, bitmap,
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se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
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free_data_area(udev, cmd);
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} else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
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gather_and_free_data_area(udev,
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DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
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bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
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gather_data_area(udev, bitmap,
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se_cmd->t_data_sg, se_cmd->t_data_nents);
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free_data_area(udev, cmd);
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} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
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free_data_area(udev, cmd->data_length);
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free_data_area(udev, cmd);
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} else if (se_cmd->data_direction != DMA_NONE) {
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pr_warn("TCMU: data direction was %d!\n",
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se_cmd->data_direction);
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@ -912,6 +932,7 @@ static int tcmu_configure_device(struct se_device *dev)
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WARN_ON(!PAGE_ALIGNED(udev->data_off));
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WARN_ON(udev->data_size % PAGE_SIZE);
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WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
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info->version = __stringify(TCMU_MAILBOX_VERSION);
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