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target: rewrite fd_execute_write_same 

With the new bio_vec backed iov_iter helpers we can simply set up
on bio_vec per LBA, all pointing to the same initiator-supplied
buffer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Christoph Hellwig 2015-02-22 08:48:42 -08:00 committed by Nicholas Bellinger
parent 6b9a44d093
commit d4c5dcacfa
1 changed files with 22 additions and 78 deletions
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100
drivers/target/target_core_file.c
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@ -433,59 +433,17 @@ fd_execute_sync_cache(struct se_cmd *cmd)
return 0;
}
static unsigned char *
fd_setup_write_same_buf(struct se_cmd *cmd, struct scatterlist *sg,
unsigned int len)
{
struct se_device *se_dev = cmd->se_dev;
unsigned int block_size = se_dev->dev_attrib.block_size;
unsigned int i = 0, end;
unsigned char *buf, *p, *kmap_buf;
buf = kzalloc(min_t(unsigned int, len, PAGE_SIZE), GFP_KERNEL);
if (!buf) {
pr_err("Unable to allocate fd_execute_write_same buf\n");
return NULL;
}
kmap_buf = kmap(sg_page(sg)) + sg->offset;
if (!kmap_buf) {
pr_err("kmap() failed in fd_setup_write_same\n");
kfree(buf);
return NULL;
}
/*
* Fill local *buf to contain multiple WRITE_SAME blocks up to
* min(len, PAGE_SIZE)
*/
p = buf;
end = min_t(unsigned int, len, PAGE_SIZE);
while (i < end) {
memcpy(p, kmap_buf, block_size);
i += block_size;
p += block_size;
}
kunmap(sg_page(sg));
return buf;
}
static sense_reason_t
fd_execute_write_same(struct se_cmd *cmd)
{
struct se_device *se_dev = cmd->se_dev;
struct fd_dev *fd_dev = FD_DEV(se_dev);
struct file *f = fd_dev->fd_file;
struct scatterlist *sg;
struct iovec *iov;
mm_segment_t old_fs;
sector_t nolb = sbc_get_write_same_sectors(cmd);
loff_t pos = cmd->t_task_lba * se_dev->dev_attrib.block_size;
unsigned int len, len_tmp, iov_num;
int i, rc;
unsigned char *buf;
sector_t nolb = sbc_get_write_same_sectors(cmd);
struct iov_iter iter;
struct bio_vec *bvec;
unsigned int len = 0, i;
ssize_t ret;
if (!nolb) {
target_complete_cmd(cmd, SAM_STAT_GOOD);
@ -496,49 +454,35 @@ fd_execute_write_same(struct se_cmd *cmd)
" backends not supported\n");
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
sg = &cmd->t_data_sg[0];
if (cmd->t_data_nents > 1 ||
sg->length != cmd->se_dev->dev_attrib.block_size) {
cmd->t_data_sg[0].length != cmd->se_dev->dev_attrib.block_size) {
pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
" block_size: %u\n", cmd->t_data_nents, sg->length,
" block_size: %u\n",
cmd->t_data_nents,
cmd->t_data_sg[0].length,
cmd->se_dev->dev_attrib.block_size);
return TCM_INVALID_CDB_FIELD;
}
len = len_tmp = nolb * se_dev->dev_attrib.block_size;
iov_num = DIV_ROUND_UP(len, PAGE_SIZE);
buf = fd_setup_write_same_buf(cmd, sg, len);
if (!buf)
bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
if (!bvec)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
iov = vzalloc(sizeof(struct iovec) * iov_num);
if (!iov) {
pr_err("Unable to allocate fd_execute_write_same iovecs\n");
kfree(buf);
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
/*
* Map the single fabric received scatterlist block now populated
* in *buf into each iovec for I/O submission.
*/
for (i = 0; i < iov_num; i++) {
iov[i].iov_base = buf;
iov[i].iov_len = min_t(unsigned int, len_tmp, PAGE_SIZE);
len_tmp -= iov[i].iov_len;
for (i = 0; i < nolb; i++) {
bvec[i].bv_page = sg_page(&cmd->t_data_sg[0]);
bvec[i].bv_len = cmd->t_data_sg[0].length;
bvec[i].bv_offset = cmd->t_data_sg[0].offset;
len += se_dev->dev_attrib.block_size;
}
old_fs = get_fs();
set_fs(get_ds());
rc = vfs_writev(f, &iov[0], iov_num, &pos);
set_fs(old_fs);
iov_iter_bvec(&iter, ITER_BVEC, bvec, nolb, len);
ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos);
vfree(iov);
kfree(buf);
if (rc < 0 || rc != len) {
pr_err("vfs_writev() returned %d for write same\n", rc);
kfree(bvec);
if (ret < 0 || ret != len) {
pr_err("vfs_iter_write() returned %zd for write same\n", ret);
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}