@@ -499,7 +499,6 @@ void target_xcopy_release_pt(void)
* @cdb: SCSI CDB to be copied into @xpt_cmd.
* @remote_port: If false, use the LUN through which the XCOPY command has
* been received. If true, use @se_dev->xcopy_lun.
- * @alloc_mem: Whether or not to allocate an SGL list.
*
* Set up a SCSI command (READ or WRITE) that will be used to execute an
* XCOPY command.
@@ -509,12 +508,11 @@ static int target_xcopy_setup_pt_cmd(
struct xcopy_op *xop,
struct se_device *se_dev,
unsigned char *cdb,
- bool remote_port,
- bool alloc_mem)
+ bool remote_port)
{
struct se_cmd *cmd = &xpt_cmd->se_cmd;
sense_reason_t sense_rc;
- int ret = 0, rc;
+ int ret = 0;
/*
* Setup LUN+port to honor reservations based upon xop->op_origin for
@@ -536,36 +534,21 @@ static int target_xcopy_setup_pt_cmd(
goto out;
}
- if (alloc_mem) {
- rc = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
- cmd->data_length, false, false);
- if (rc < 0) {
- ret = rc;
- goto out;
- }
- /*
- * Set this bit so that transport_free_pages() allows the
- * caller to release SGLs + physical memory allocated by
- * transport_generic_get_mem()..
- */
- cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
- } else {
- /*
- * Here the previously allocated SGLs for the internal READ
- * are mapped zero-copy to the internal WRITE.
- */
- sense_rc = transport_generic_map_mem_to_cmd(cmd,
- xop->xop_data_sg, xop->xop_data_nents,
- NULL, 0);
- if (sense_rc) {
- ret = -EINVAL;
- goto out;
- }
-
- pr_debug("Setup PASSTHROUGH_NOALLOC t_data_sg: %p t_data_nents:"
- " %u\n", cmd->t_data_sg, cmd->t_data_nents);
+ /*
+ * Here the previously allocated SGLs for the XCOPY are mapped zero-copy
+ * to the internal READ or WRITE.
+ */
+ sense_rc = transport_generic_map_mem_to_cmd(cmd,
+ xop->xop_data_sg, xop->xop_data_nents,
+ NULL, 0);
+ if (sense_rc) {
+ ret = -EINVAL;
+ goto out;
}
+ pr_debug("Setup PASSTHROUGH_NOALLOC t_data_sg: %p t_data_nents:"
+ " %u\n", cmd->t_data_sg, cmd->t_data_nents);
+
return 0;
out:
@@ -626,15 +609,13 @@ static int target_xcopy_read_source(
xop->src_pt_cmd = xpt_cmd;
rc = target_xcopy_setup_pt_cmd(xpt_cmd, xop, src_dev, &cdb[0],
- remote_port, true);
+ remote_port);
if (rc < 0) {
ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
transport_generic_free_cmd(se_cmd, 0);
return rc;
}
- xop->xop_data_sg = se_cmd->t_data_sg;
- xop->xop_data_nents = se_cmd->t_data_nents;
pr_debug("XCOPY-READ: Saved xop->xop_data_sg: %p, num: %u for READ"
" memory\n", xop->xop_data_sg, xop->xop_data_nents);
@@ -644,12 +625,6 @@ static int target_xcopy_read_source(
transport_generic_free_cmd(se_cmd, 0);
return rc;
}
- /*
- * Clear off the allocated t_data_sg, that has been saved for
- * zero-copy WRITE submission reuse in struct xcopy_op..
- */
- se_cmd->t_data_sg = NULL;
- se_cmd->t_data_nents = 0;
return 0;
}
@@ -688,19 +663,9 @@ static int target_xcopy_write_destination(
xop->dst_pt_cmd = xpt_cmd;
rc = target_xcopy_setup_pt_cmd(xpt_cmd, xop, dst_dev, &cdb[0],
- remote_port, false);
+ remote_port);
if (rc < 0) {
- struct se_cmd *src_cmd = &xop->src_pt_cmd->se_cmd;
ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
- /*
- * If the failure happened before the t_mem_list hand-off in
- * target_xcopy_setup_pt_cmd(), Reset memory + clear flag so that
- * core releases this memory on error during X-COPY WRITE I/O.
- */
- src_cmd->se_cmd_flags &= ~SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
- src_cmd->t_data_sg = xop->xop_data_sg;
- src_cmd->t_data_nents = xop->xop_data_nents;
-
transport_generic_free_cmd(se_cmd, 0);
return rc;
}
@@ -708,7 +673,6 @@ static int target_xcopy_write_destination(
rc = target_xcopy_issue_pt_cmd(xpt_cmd);
if (rc < 0) {
ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
- se_cmd->se_cmd_flags &= ~SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
transport_generic_free_cmd(se_cmd, 0);
return rc;
}
@@ -724,7 +688,7 @@ static void target_xcopy_do_work(struct work_struct *work)
sector_t src_lba, dst_lba, end_lba;
unsigned int max_sectors;
int rc = 0;
- unsigned short nolb, cur_nolb, max_nolb, copied_nolb = 0;
+ unsigned short nolb, max_nolb, copied_nolb = 0;
if (target_parse_xcopy_cmd(xop) != TCM_NO_SENSE)
goto err_free;
@@ -754,7 +718,24 @@ static void target_xcopy_do_work(struct work_struct *work)
(unsigned long long)src_lba, (unsigned long long)dst_lba);
while (src_lba < end_lba) {
- cur_nolb = min(nolb, max_nolb);
+ unsigned short cur_nolb = min(nolb, max_nolb);
+ u32 cur_bytes = cur_nolb * src_dev->dev_attrib.block_size;
+
+ if (cur_bytes != xop->xop_data_bytes) {
+ /*
+ * (Re)allocate a buffer large enough to hold the XCOPY
+ * I/O size, which can be reused each read / write loop.
+ */
+ target_free_sgl(xop->xop_data_sg, xop->xop_data_nents);
+ rc = target_alloc_sgl(&xop->xop_data_sg,
+ &xop->xop_data_nents,
+ cur_bytes,
+ false, false);
+ if (rc < 0) {
+ goto out;
+ }
+ xop->xop_data_bytes = cur_bytes;
+ }
pr_debug("target_xcopy_do_work: Calling read src_dev: %p src_lba: %llu,"
" cur_nolb: %hu\n", src_dev, (unsigned long long)src_lba, cur_nolb);
@@ -785,12 +766,11 @@ static void target_xcopy_do_work(struct work_struct *work)
nolb -= cur_nolb;
transport_generic_free_cmd(&xop->src_pt_cmd->se_cmd, 0);
- xop->dst_pt_cmd->se_cmd.se_cmd_flags &= ~SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
-
transport_generic_free_cmd(&xop->dst_pt_cmd->se_cmd, 0);
}
xcopy_pt_undepend_remotedev(xop);
+ target_free_sgl(xop->xop_data_sg, xop->xop_data_nents);
kfree(xop);
pr_debug("target_xcopy_do_work: Final src_lba: %llu, dst_lba: %llu\n",
@@ -804,6 +784,7 @@ static void target_xcopy_do_work(struct work_struct *work)
out:
xcopy_pt_undepend_remotedev(xop);
+ target_free_sgl(xop->xop_data_sg, xop->xop_data_nents);
err_free:
kfree(xop);
@@ -39,6 +39,7 @@ struct xcopy_op {
struct xcopy_pt_cmd *src_pt_cmd;
struct xcopy_pt_cmd *dst_pt_cmd;
+ u32 xop_data_bytes;
u32 xop_data_nents;
struct scatterlist *xop_data_sg;
struct work_struct xop_work;
The main target_xcopy_do_work() loop unnecessarily allocates an I/O buffer with each synchronous READ / WRITE pair. This commit significantly reduces allocations by reusing the XCOPY I/O buffer when possible. Signed-off-by: David Disseldorp <ddiss@suse.de> --- drivers/target/target_core_xcopy.c | 95 +++++++++++++++----------------------- drivers/target/target_core_xcopy.h | 1 + 2 files changed, 39 insertions(+), 57 deletions(-)