Removing the percpu_ida code nets over 400 lines of removal. It's not as spectacular as deleting an entire architecture, but it's still a worthy reduction in lines of code. Untested due to lack of hardware and not understanding how to set up a target platform. Changes from v1: - Fixed bugs pointed out by Jens in iscsit_wait_for_tag() - Abstracted out tag freeing as requested by Bart - Made iscsit_wait_for_tag static as pointed out by 0day Matthew Wilcox (3): target: Abstract tag freeing Convert target drivers to use sbitmap Remove percpu_ida drivers/scsi/qla2xxx/qla_target.c | 14 +- drivers/target/iscsi/iscsi_target_util.c | 35 ++- drivers/target/sbp/sbp_target.c | 7 +- drivers/target/target_core_transport.c | 5 +- drivers/target/tcm_fc/tfc_cmd.c | 10 +- drivers/usb/gadget/function/f_tcm.c | 7 +- drivers/vhost/scsi.c | 8 +- drivers/xen/xen-scsiback.c | 9 +- include/linux/percpu_ida.h | 83 ----- include/target/iscsi/iscsi_target_core.h | 1 + include/target/target_core_base.h | 10 +- lib/Makefile | 2 +- lib/percpu_ida.c | 370 ----------------------- 13 files changed, 73 insertions(+), 488 deletions(-) delete mode 100644 include/linux/percpu_ida.h delete mode 100644 lib/percpu_ida.c -- 2.17.1
Introduce target_free_tag() and convert all drivers to use it.
Signed-off-by: Matthew Wilcox <willy at infradead.org>
---
drivers/scsi/qla2xxx/qla_target.c | 4 ++--
drivers/target/iscsi/iscsi_target_util.c | 2 +-
drivers/target/sbp/sbp_target.c | 2 +-
drivers/target/tcm_fc/tfc_cmd.c | 4 ++--
drivers/usb/gadget/function/f_tcm.c | 2 +-
drivers/vhost/scsi.c | 2 +-
drivers/xen/xen-scsiback.c | 4 +---
include/target/target_core_base.h | 5 +++++
8 files changed, 14 insertions(+), 11 deletions(-)
diff --git a/drivers/scsi/qla2xxx/qla_target.c
b/drivers/scsi/qla2xxx/qla_target.c
index b85c833099ff..05290966e630 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -3783,7 +3783,7 @@ void qlt_free_cmd(struct qla_tgt_cmd *cmd)
return;
}
cmd->jiffies_at_free = get_jiffies_64();
- percpu_ida_free(&sess->se_sess->sess_tag_pool,
cmd->se_cmd.map_tag);
+ target_free_tag(sess->se_sess, &cmd->se_cmd);
}
EXPORT_SYMBOL(qlt_free_cmd);
@@ -4146,7 +4146,7 @@ static void __qlt_do_work(struct qla_tgt_cmd *cmd)
qlt_send_term_exchange(qpair, NULL, &cmd->atio, 1, 0);
qlt_decr_num_pend_cmds(vha);
- percpu_ida_free(&sess->se_sess->sess_tag_pool,
cmd->se_cmd.map_tag);
+ target_free_tag(sess->se_sess, &cmd->se_cmd);
spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
spin_lock_irqsave(&ha->tgt.sess_lock, flags);
diff --git a/drivers/target/iscsi/iscsi_target_util.c
b/drivers/target/iscsi/iscsi_target_util.c
index 4435bf374d2d..7e98697cfb8e 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -711,7 +711,7 @@ void iscsit_release_cmd(struct iscsi_cmd *cmd)
kfree(cmd->iov_data);
kfree(cmd->text_in_ptr);
- percpu_ida_free(&sess->se_sess->sess_tag_pool, se_cmd->map_tag);
+ target_free_tag(sess->se_sess, se_cmd);
}
EXPORT_SYMBOL(iscsit_release_cmd);
diff --git a/drivers/target/sbp/sbp_target.c b/drivers/target/sbp/sbp_target.c
index fb1003921d85..679ae29d25ab 100644
--- a/drivers/target/sbp/sbp_target.c
+++ b/drivers/target/sbp/sbp_target.c
@@ -1460,7 +1460,7 @@ static void sbp_free_request(struct sbp_target_request
*req)
kfree(req->pg_tbl);
kfree(req->cmd_buf);
- percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
+ target_free_tag(se_sess, se_cmd);
}
static void sbp_mgt_agent_process(struct work_struct *work)
diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index ec372860106f..13e4efbe1ce7 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -92,7 +92,7 @@ static void ft_free_cmd(struct ft_cmd *cmd)
if (fr_seq(fp))
fc_seq_release(fr_seq(fp));
fc_frame_free(fp);
- percpu_ida_free(&sess->se_sess->sess_tag_pool,
cmd->se_cmd.map_tag);
+ target_free_tag(sess->se_sess, &cmd->se_cmd);
ft_sess_put(sess); /* undo get from lookup at recv */
}
@@ -461,7 +461,7 @@ static void ft_recv_cmd(struct ft_sess *sess, struct
fc_frame *fp)
cmd->sess = sess;
cmd->seq = fc_seq_assign(lport, fp);
if (!cmd->seq) {
- percpu_ida_free(&se_sess->sess_tag_pool, tag);
+ target_free_tag(se_sess, &cmd->se_cmd);
goto busy;
}
cmd->req_frame = fp; /* hold frame during cmd */
diff --git a/drivers/usb/gadget/function/f_tcm.c
b/drivers/usb/gadget/function/f_tcm.c
index d78dbb73bde8..9f670d9224b9 100644
--- a/drivers/usb/gadget/function/f_tcm.c
+++ b/drivers/usb/gadget/function/f_tcm.c
@@ -1288,7 +1288,7 @@ static void usbg_release_cmd(struct se_cmd *se_cmd)
struct se_session *se_sess = se_cmd->se_sess;
kfree(cmd->data_buf);
- percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
+ target_free_tag(se_sess, se_cmd);
}
static u32 usbg_sess_get_index(struct se_session *se_sess)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 7ad57094d736..70d35e696533 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -324,7 +324,7 @@ static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)
}
vhost_scsi_put_inflight(tv_cmd->inflight);
- percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
+ target_free_tag(se_sess, se_cmd);
}
static u32 vhost_scsi_sess_get_index(struct se_session *se_sess)
diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index 7bc88fd43cfc..ec6635258ed8 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -1377,9 +1377,7 @@ static int scsiback_check_stop_free(struct se_cmd *se_cmd)
static void scsiback_release_cmd(struct se_cmd *se_cmd)
{
- struct se_session *se_sess = se_cmd->se_sess;
-
- percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
+ target_free_tag(se_cmd->se_sess, se_cmd);
}
static u32 scsiback_sess_get_index(struct se_session *se_sess)
diff --git a/include/target/target_core_base.h
b/include/target/target_core_base.h
index 922a39f45abc..260c2f3e9460 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -934,4 +934,9 @@ static inline void atomic_dec_mb(atomic_t *v)
smp_mb__after_atomic();
}
+static inline void target_free_tag(struct se_session *sess, struct se_cmd *cmd)
+{
+ percpu_ida_free(&sess->sess_tag_pool, cmd->map_tag);
+}
+
#endif /* TARGET_CORE_BASE_H */
--
2.17.1
The sbitmap and the percpu_ida perform essentially the same task,
allocating tags for commands. The sbitmap outperforms the percpu_ida
as documented here: https://lkml.org/lkml/2014/4/22/553
The sbitmap interface is a little harder to use, but being able to
remove the percpu_ida code and getting better performance justifies the
additional complexity.
Signed-off-by: Matthew Wilcox <willy at infradead.org>
Acked-by: Felipe Balbi <felipe.balbi at linux.intel.com> # f_tcm
---
drivers/scsi/qla2xxx/qla_target.c | 10 ++++---
drivers/target/iscsi/iscsi_target_util.c | 33 +++++++++++++++++++++---
drivers/target/sbp/sbp_target.c | 5 ++--
drivers/target/target_core_transport.c | 5 ++--
drivers/target/tcm_fc/tfc_cmd.c | 6 ++---
drivers/usb/gadget/function/f_tcm.c | 5 ++--
drivers/vhost/scsi.c | 6 ++---
drivers/xen/xen-scsiback.c | 5 ++--
include/target/iscsi/iscsi_target_core.h | 1 +
include/target/target_core_base.h | 7 ++---
10 files changed, 59 insertions(+), 24 deletions(-)
diff --git a/drivers/scsi/qla2xxx/qla_target.c
b/drivers/scsi/qla2xxx/qla_target.c
index 05290966e630..a1725a054749 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -4277,9 +4277,9 @@ static struct qla_tgt_cmd *qlt_get_tag(scsi_qla_host_t
*vha,
{
struct se_session *se_sess = sess->se_sess;
struct qla_tgt_cmd *cmd;
- int tag;
+ int tag, cpu;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0)
return NULL;
@@ -4292,6 +4292,7 @@ static struct qla_tgt_cmd *qlt_get_tag(scsi_qla_host_t
*vha,
qlt_incr_num_pend_cmds(vha);
cmd->vha = vha;
cmd->se_cmd.map_tag = tag;
+ cmd->se_cmd.map_cpu = cpu;
cmd->sess = sess;
cmd->loop_id = sess->loop_id;
cmd->conf_compl_supported = sess->conf_compl_supported;
@@ -5294,7 +5295,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha,
struct fc_port *sess;
struct se_session *se_sess;
struct qla_tgt_cmd *cmd;
- int tag;
+ int tag, cpu;
unsigned long flags;
if (unlikely(tgt->tgt_stop)) {
@@ -5326,7 +5327,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha,
se_sess = sess->se_sess;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0)
return;
@@ -5357,6 +5358,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha,
cmd->reset_count = ha->base_qpair->chip_reset;
cmd->q_full = 1;
cmd->qpair = ha->base_qpair;
+ cmd->se_cmd.map_cpu = cpu;
if (qfull) {
cmd->q_full = 1;
diff --git a/drivers/target/iscsi/iscsi_target_util.c
b/drivers/target/iscsi/iscsi_target_util.c
index 7e98697cfb8e..8cfcf9033507 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -17,7 +17,7 @@
******************************************************************************/
#include <linux/list.h>
-#include <linux/percpu_ida.h>
+#include <linux/sched/signal.h>
#include <net/ipv6.h> /* ipv6_addr_equal() */
#include <scsi/scsi_tcq.h>
#include <scsi/iscsi_proto.h>
@@ -147,6 +147,30 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
spin_unlock_bh(&cmd->r2t_lock);
}
+static int iscsit_wait_for_tag(struct se_session *se_sess, int state, int
*cpup)
+{
+ int tag = -1;
+ DEFINE_WAIT(wait);
+ struct sbq_wait_state *ws;
+
+ if (state == TASK_RUNNING)
+ return tag;
+
+ ws = &se_sess->sess_tag_pool.ws[0];
+ for (;;) {
+ prepare_to_wait_exclusive(&ws->wait, &wait, state);
+ if (signal_pending_state(state, current))
+ break;
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, cpup);
+ if (tag >= 0)
+ break;
+ schedule();
+ }
+
+ finish_wait(&ws->wait, &wait);
+ return tag;
+}
+
/*
* May be called from software interrupt (timer) context for allocating
* iSCSI NopINs.
@@ -155,9 +179,11 @@ struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn
*conn, int state)
{
struct iscsi_cmd *cmd;
struct se_session *se_sess = conn->sess->se_sess;
- int size, tag;
+ int size, tag, cpu;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
+ if (tag < 0)
+ tag = iscsit_wait_for_tag(se_sess, state, &cpu);
if (tag < 0)
return NULL;
@@ -166,6 +192,7 @@ struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn
*conn, int state)
memset(cmd, 0, size);
cmd->se_cmd.map_tag = tag;
+ cmd->se_cmd.map_cpu = cpu;
cmd->conn = conn;
cmd->data_direction = DMA_NONE;
INIT_LIST_HEAD(&cmd->i_conn_node);
diff --git a/drivers/target/sbp/sbp_target.c b/drivers/target/sbp/sbp_target.c
index 679ae29d25ab..42b21f2ac8b0 100644
--- a/drivers/target/sbp/sbp_target.c
+++ b/drivers/target/sbp/sbp_target.c
@@ -926,15 +926,16 @@ static struct sbp_target_request *sbp_mgt_get_req(struct
sbp_session *sess,
{
struct se_session *se_sess = sess->se_sess;
struct sbp_target_request *req;
- int tag;
+ int tag, cpu;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0)
return ERR_PTR(-ENOMEM);
req = &((struct sbp_target_request *)se_sess->sess_cmd_map)[tag];
memset(req, 0, sizeof(*req));
req->se_cmd.map_tag = tag;
+ req->se_cmd.map_cpu = cpu;
req->se_cmd.tag = next_orb;
return req;
diff --git a/drivers/target/target_core_transport.c
b/drivers/target/target_core_transport.c
index f0e8f0f4ccb4..18c53c5cdd3d 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -260,7 +260,8 @@ int transport_alloc_session_tags(struct se_session *se_sess,
}
}
- rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
+ rc = sbitmap_queue_init_node(&se_sess->sess_tag_pool, tag_num, -1,
+ false, GFP_KERNEL, NUMA_NO_NODE);
if (rc < 0) {
pr_err("Unable to init se_sess->sess_tag_pool,"
" tag_num: %u\n", tag_num);
@@ -547,7 +548,7 @@ void transport_free_session(struct se_session *se_sess)
target_put_nacl(se_nacl);
}
if (se_sess->sess_cmd_map) {
- percpu_ida_destroy(&se_sess->sess_tag_pool);
+ sbitmap_queue_free(&se_sess->sess_tag_pool);
kvfree(se_sess->sess_cmd_map);
}
kmem_cache_free(se_sess_cache, se_sess);
diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index 13e4efbe1ce7..a183d4da7db2 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -28,7 +28,6 @@
#include <linux/configfs.h>
#include <linux/ctype.h>
#include <linux/hash.h>
-#include <linux/percpu_ida.h>
#include <asm/unaligned.h>
#include <scsi/scsi_tcq.h>
#include <scsi/libfc.h>
@@ -448,9 +447,9 @@ static void ft_recv_cmd(struct ft_sess *sess, struct
fc_frame *fp)
struct ft_cmd *cmd;
struct fc_lport *lport = sess->tport->lport;
struct se_session *se_sess = sess->se_sess;
- int tag;
+ int tag, cpu;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0)
goto busy;
@@ -458,6 +457,7 @@ static void ft_recv_cmd(struct ft_sess *sess, struct
fc_frame *fp)
memset(cmd, 0, sizeof(struct ft_cmd));
cmd->se_cmd.map_tag = tag;
+ cmd->se_cmd.map_cpu = cpu;
cmd->sess = sess;
cmd->seq = fc_seq_assign(lport, fp);
if (!cmd->seq) {
diff --git a/drivers/usb/gadget/function/f_tcm.c
b/drivers/usb/gadget/function/f_tcm.c
index 9f670d9224b9..5003e857dce7 100644
--- a/drivers/usb/gadget/function/f_tcm.c
+++ b/drivers/usb/gadget/function/f_tcm.c
@@ -1071,15 +1071,16 @@ static struct usbg_cmd *usbg_get_cmd(struct f_uas *fu,
{
struct se_session *se_sess = tv_nexus->tvn_se_sess;
struct usbg_cmd *cmd;
- int tag;
+ int tag, cpu;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0)
return ERR_PTR(-ENOMEM);
cmd = &((struct usbg_cmd *)se_sess->sess_cmd_map)[tag];
memset(cmd, 0, sizeof(*cmd));
cmd->se_cmd.map_tag = tag;
+ cmd->se_cmd.map_cpu = cpu;
cmd->se_cmd.tag = cmd->tag = scsi_tag;
cmd->fu = fu;
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 70d35e696533..c9c5d6b291cc 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -46,7 +46,6 @@
#include <linux/virtio_scsi.h>
#include <linux/llist.h>
#include <linux/bitmap.h>
-#include <linux/percpu_ida.h>
#include "vhost.h"
@@ -567,7 +566,7 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct
vhost_scsi_tpg *tpg,
struct se_session *se_sess;
struct scatterlist *sg, *prot_sg;
struct page **pages;
- int tag;
+ int tag, cpu;
tv_nexus = tpg->tpg_nexus;
if (!tv_nexus) {
@@ -576,7 +575,7 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct
vhost_scsi_tpg *tpg,
}
se_sess = tv_nexus->tvn_se_sess;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0) {
pr_err("Unable to obtain tag for vhost_scsi_cmd\n");
return ERR_PTR(-ENOMEM);
@@ -591,6 +590,7 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct
vhost_scsi_tpg *tpg,
cmd->tvc_prot_sgl = prot_sg;
cmd->tvc_upages = pages;
cmd->tvc_se_cmd.map_tag = tag;
+ cmd->tvc_se_cmd.map_cpu = cpu;
cmd->tvc_tag = scsi_tag;
cmd->tvc_lun = lun;
cmd->tvc_task_attr = task_attr;
diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index ec6635258ed8..764dd9aa0131 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -654,9 +654,9 @@ static struct vscsibk_pend *scsiback_get_pend_req(struct
vscsiif_back_ring *ring
struct scsiback_nexus *nexus = tpg->tpg_nexus;
struct se_session *se_sess = nexus->tvn_se_sess;
struct vscsibk_pend *req;
- int tag, i;
+ int tag, cpu, i;
- tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0) {
pr_err("Unable to obtain tag for vscsiif_request\n");
return ERR_PTR(-ENOMEM);
@@ -665,6 +665,7 @@ static struct vscsibk_pend *scsiback_get_pend_req(struct
vscsiif_back_ring *ring
req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
memset(req, 0, sizeof(*req));
req->se_cmd.map_tag = tag;
+ req->se_cmd.map_cpu = cpu;
for (i = 0; i < VSCSI_MAX_GRANTS; i++)
req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
diff --git a/include/target/iscsi/iscsi_target_core.h
b/include/target/iscsi/iscsi_target_core.h
index cf5f3fff1f1a..f2e6abea8490 100644
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -4,6 +4,7 @@
#include <linux/dma-direction.h> /* enum dma_data_direction */
#include <linux/list.h> /* struct list_head */
+#include <linux/sched.h>
#include <linux/socket.h> /* struct sockaddr_storage */
#include <linux/types.h> /* u8 */
#include <scsi/iscsi_proto.h> /* itt_t */
diff --git a/include/target/target_core_base.h
b/include/target/target_core_base.h
index 260c2f3e9460..448f291125c2 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -4,7 +4,7 @@
#include <linux/configfs.h> /* struct config_group */
#include <linux/dma-direction.h> /* enum dma_data_direction */
-#include <linux/percpu_ida.h> /* struct percpu_ida */
+#include <linux/sbitmap.h>
#include <linux/percpu-refcount.h>
#include <linux/semaphore.h> /* struct semaphore */
#include <linux/completion.h>
@@ -455,6 +455,7 @@ struct se_cmd {
int sam_task_attr;
/* Used for se_sess->sess_tag_pool */
unsigned int map_tag;
+ int map_cpu;
/* Transport protocol dependent state, see transport_state_table */
enum transport_state_table t_state;
/* See se_cmd_flags_table */
@@ -608,7 +609,7 @@ struct se_session {
struct list_head sess_wait_list;
spinlock_t sess_cmd_lock;
void *sess_cmd_map;
- struct percpu_ida sess_tag_pool;
+ struct sbitmap_queue sess_tag_pool;
};
struct se_device;
@@ -936,7 +937,7 @@ static inline void atomic_dec_mb(atomic_t *v)
static inline void target_free_tag(struct se_session *sess, struct se_cmd *cmd)
{
- percpu_ida_free(&sess->sess_tag_pool, cmd->map_tag);
+ sbitmap_queue_clear(&sess->sess_tag_pool, cmd->map_tag,
cmd->map_cpu);
}
#endif /* TARGET_CORE_BASE_H */
--
2.17.1
With its one user gone, remove the library code.
Signed-off-by: Matthew Wilcox <willy at infradead.org>
---
include/linux/percpu_ida.h | 83 ---------
lib/Makefile | 2 +-
lib/percpu_ida.c | 370 -------------------------------------
3 files changed, 1 insertion(+), 454 deletions(-)
delete mode 100644 include/linux/percpu_ida.h
delete mode 100644 lib/percpu_ida.c
diff --git a/include/linux/percpu_ida.h b/include/linux/percpu_ida.h
deleted file mode 100644
index 07d78e4653bc..000000000000
--- a/include/linux/percpu_ida.h
+++ /dev/null
@@ -1,83 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __PERCPU_IDA_H__
-#define __PERCPU_IDA_H__
-
-#include <linux/types.h>
-#include <linux/bitops.h>
-#include <linux/init.h>
-#include <linux/sched.h>
-#include <linux/spinlock_types.h>
-#include <linux/wait.h>
-#include <linux/cpumask.h>
-
-struct percpu_ida_cpu;
-
-struct percpu_ida {
- /*
- * number of tags available to be allocated, as passed to
- * percpu_ida_init()
- */
- unsigned nr_tags;
- unsigned percpu_max_size;
- unsigned percpu_batch_size;
-
- struct percpu_ida_cpu __percpu *tag_cpu;
-
- /*
- * Bitmap of cpus that (may) have tags on their percpu freelists:
- * steal_tags() uses this to decide when to steal tags, and which cpus
- * to try stealing from.
- *
- * It's ok for a freelist to be empty when its bit is set - steal_tags()
- * will just keep looking - but the bitmap _must_ be set whenever a
- * percpu freelist does have tags.
- */
- cpumask_t cpus_have_tags;
-
- struct {
- spinlock_t lock;
- /*
- * When we go to steal tags from another cpu (see steal_tags()),
- * we want to pick a cpu at random. Cycling through them every
- * time we steal is a bit easier and more or less equivalent:
- */
- unsigned cpu_last_stolen;
-
- /* For sleeping on allocation failure */
- wait_queue_head_t wait;
-
- /*
- * Global freelist - it's a stack where nr_free points to the
- * top
- */
- unsigned nr_free;
- unsigned *freelist;
- } ____cacheline_aligned_in_smp;
-};
-
-/*
- * Number of tags we move between the percpu freelist and the global freelist
at
- * a time
- */
-#define IDA_DEFAULT_PCPU_BATCH_MOVE 32U
-/* Max size of percpu freelist, */
-#define IDA_DEFAULT_PCPU_SIZE ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)
-
-int percpu_ida_alloc(struct percpu_ida *pool, int state);
-void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
-
-void percpu_ida_destroy(struct percpu_ida *pool);
-int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
- unsigned long max_size, unsigned long batch_size);
-static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long
nr_tags)
-{
- return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE,
- IDA_DEFAULT_PCPU_BATCH_MOVE);
-}
-
-typedef int (*percpu_ida_cb)(unsigned, void *);
-int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
- void *data);
-
-unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
-#endif /* __PERCPU_IDA_H__ */
diff --git a/lib/Makefile b/lib/Makefile
index 84c6dcb31fbb..f4722a7fa62c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -40,7 +40,7 @@ obj-y += bcd.o div64.o sort.o parser.o debug_locks.o
random32.o \
bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \
gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \
bsearch.o find_bit.o llist.o memweight.o kfifo.o \
- percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o \
+ percpu-refcount.o rhashtable.o reciprocal_div.o \
once.o refcount.o usercopy.o errseq.o bucket_locks.o
obj-$(CONFIG_STRING_SELFTEST) += test_string.o
obj-y += string_helpers.o
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
deleted file mode 100644
index 9bbd9c5d375a..000000000000
--- a/lib/percpu_ida.c
+++ /dev/null
@@ -1,370 +0,0 @@
-/*
- * Percpu IDA library
- *
- * Copyright (C) 2013 Datera, Inc. Kent Overstreet
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- */
-
-#include <linux/mm.h>
-#include <linux/bitmap.h>
-#include <linux/bitops.h>
-#include <linux/bug.h>
-#include <linux/err.h>
-#include <linux/export.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/percpu.h>
-#include <linux/sched/signal.h>
-#include <linux/string.h>
-#include <linux/spinlock.h>
-#include <linux/percpu_ida.h>
-
-struct percpu_ida_cpu {
- /*
- * Even though this is percpu, we need a lock for tag stealing by remote
- * CPUs:
- */
- spinlock_t lock;
-
- /* nr_free/freelist form a stack of free IDs */
- unsigned nr_free;
- unsigned freelist[];
-};
-
-static inline void move_tags(unsigned *dst, unsigned *dst_nr,
- unsigned *src, unsigned *src_nr,
- unsigned nr)
-{
- *src_nr -= nr;
- memcpy(dst + *dst_nr, src + *src_nr, sizeof(unsigned) * nr);
- *dst_nr += nr;
-}
-
-/*
- * Try to steal tags from a remote cpu's percpu freelist.
- *
- * We first check how many percpu freelists have tags
- *
- * Then we iterate through the cpus until we find some tags - we don't
attempt
- * to find the "best" cpu to steal from, to keep cacheline bouncing
to a
- * minimum.
- */
-static inline void steal_tags(struct percpu_ida *pool,
- struct percpu_ida_cpu *tags)
-{
- unsigned cpus_have_tags, cpu = pool->cpu_last_stolen;
- struct percpu_ida_cpu *remote;
-
- for (cpus_have_tags = cpumask_weight(&pool->cpus_have_tags);
- cpus_have_tags; cpus_have_tags--) {
- cpu = cpumask_next(cpu, &pool->cpus_have_tags);
-
- if (cpu >= nr_cpu_ids) {
- cpu = cpumask_first(&pool->cpus_have_tags);
- if (cpu >= nr_cpu_ids)
- BUG();
- }
-
- pool->cpu_last_stolen = cpu;
- remote = per_cpu_ptr(pool->tag_cpu, cpu);
-
- cpumask_clear_cpu(cpu, &pool->cpus_have_tags);
-
- if (remote == tags)
- continue;
-
- spin_lock(&remote->lock);
-
- if (remote->nr_free) {
- memcpy(tags->freelist,
- remote->freelist,
- sizeof(unsigned) * remote->nr_free);
-
- tags->nr_free = remote->nr_free;
- remote->nr_free = 0;
- }
-
- spin_unlock(&remote->lock);
-
- if (tags->nr_free)
- break;
- }
-}
-
-/*
- * Pop up to IDA_PCPU_BATCH_MOVE IDs off the global freelist, and push them
onto
- * our percpu freelist:
- */
-static inline void alloc_global_tags(struct percpu_ida *pool,
- struct percpu_ida_cpu *tags)
-{
- move_tags(tags->freelist, &tags->nr_free,
- pool->freelist, &pool->nr_free,
- min(pool->nr_free, pool->percpu_batch_size));
-}
-
-/**
- * percpu_ida_alloc - allocate a tag
- * @pool: pool to allocate from
- * @state: task state for prepare_to_wait
- *
- * Returns a tag - an integer in the range [0..nr_tags) (passed to
- * tag_pool_init()), or otherwise -ENOSPC on allocation failure.
- *
- * Safe to be called from interrupt context (assuming it isn't passed
- * TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, of course).
- *
- * @gfp indicates whether or not to wait until a free id is available (it's
not
- * used for internal memory allocations); thus if passed __GFP_RECLAIM we may
sleep
- * however long it takes until another thread frees an id (same semantics as a
- * mempool).
- *
- * Will not fail if passed TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE.
- */
-int percpu_ida_alloc(struct percpu_ida *pool, int state)
-{
- DEFINE_WAIT(wait);
- struct percpu_ida_cpu *tags;
- unsigned long flags;
- int tag = -ENOSPC;
-
- tags = raw_cpu_ptr(pool->tag_cpu);
- spin_lock_irqsave(&tags->lock, flags);
-
- /* Fastpath */
- if (likely(tags->nr_free >= 0)) {
- tag = tags->freelist[--tags->nr_free];
- spin_unlock_irqrestore(&tags->lock, flags);
- return tag;
- }
- spin_unlock_irqrestore(&tags->lock, flags);
-
- while (1) {
- spin_lock_irqsave(&pool->lock, flags);
- tags = this_cpu_ptr(pool->tag_cpu);
-
- /*
- * prepare_to_wait() must come before steal_tags(), in case
- * percpu_ida_free() on another cpu flips a bit in
- * cpus_have_tags
- *
- * global lock held and irqs disabled, don't need percpu lock
- */
- if (state != TASK_RUNNING)
- prepare_to_wait(&pool->wait, &wait, state);
-
- if (!tags->nr_free)
- alloc_global_tags(pool, tags);
- if (!tags->nr_free)
- steal_tags(pool, tags);
-
- if (tags->nr_free) {
- tag = tags->freelist[--tags->nr_free];
- if (tags->nr_free)
- cpumask_set_cpu(smp_processor_id(),
- &pool->cpus_have_tags);
- }
-
- spin_unlock_irqrestore(&pool->lock, flags);
-
- if (tag >= 0 || state == TASK_RUNNING)
- break;
-
- if (signal_pending_state(state, current)) {
- tag = -ERESTARTSYS;
- break;
- }
-
- schedule();
- }
- if (state != TASK_RUNNING)
- finish_wait(&pool->wait, &wait);
-
- return tag;
-}
-EXPORT_SYMBOL_GPL(percpu_ida_alloc);
-
-/**
- * percpu_ida_free - free a tag
- * @pool: pool @tag was allocated from
- * @tag: a tag previously allocated with percpu_ida_alloc()
- *
- * Safe to be called from interrupt context.
- */
-void percpu_ida_free(struct percpu_ida *pool, unsigned tag)
-{
- struct percpu_ida_cpu *tags;
- unsigned long flags;
- unsigned nr_free;
-
- BUG_ON(tag >= pool->nr_tags);
-
- tags = raw_cpu_ptr(pool->tag_cpu);
-
- spin_lock_irqsave(&tags->lock, flags);
- tags->freelist[tags->nr_free++] = tag;
-
- nr_free = tags->nr_free;
-
- if (nr_free == 1) {
- cpumask_set_cpu(smp_processor_id(),
- &pool->cpus_have_tags);
- wake_up(&pool->wait);
- }
- spin_unlock_irqrestore(&tags->lock, flags);
-
- if (nr_free == pool->percpu_max_size) {
- spin_lock_irqsave(&pool->lock, flags);
- spin_lock(&tags->lock);
-
- if (tags->nr_free == pool->percpu_max_size) {
- move_tags(pool->freelist, &pool->nr_free,
- tags->freelist, &tags->nr_free,
- pool->percpu_batch_size);
-
- wake_up(&pool->wait);
- }
- spin_unlock(&tags->lock);
- spin_unlock_irqrestore(&pool->lock, flags);
- }
-}
-EXPORT_SYMBOL_GPL(percpu_ida_free);
-
-/**
- * percpu_ida_destroy - release a tag pool's resources
- * @pool: pool to free
- *
- * Frees the resources allocated by percpu_ida_init().
- */
-void percpu_ida_destroy(struct percpu_ida *pool)
-{
- free_percpu(pool->tag_cpu);
- free_pages((unsigned long) pool->freelist,
- get_order(pool->nr_tags * sizeof(unsigned)));
-}
-EXPORT_SYMBOL_GPL(percpu_ida_destroy);
-
-/**
- * percpu_ida_init - initialize a percpu tag pool
- * @pool: pool to initialize
- * @nr_tags: number of tags that will be available for allocation
- *
- * Initializes @pool so that it can be used to allocate tags - integers in the
- * range [0, nr_tags). Typically, they'll be used by driver code to refer
to a
- * preallocated array of tag structures.
- *
- * Allocation is percpu, but sharding is limited by nr_tags - for best
- * performance, the workload should not span more cpus than nr_tags / 128.
- */
-int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
- unsigned long max_size, unsigned long batch_size)
-{
- unsigned i, cpu, order;
-
- memset(pool, 0, sizeof(*pool));
-
- init_waitqueue_head(&pool->wait);
- spin_lock_init(&pool->lock);
- pool->nr_tags = nr_tags;
- pool->percpu_max_size = max_size;
- pool->percpu_batch_size = batch_size;
-
- /* Guard against overflow */
- if (nr_tags > (unsigned) INT_MAX + 1) {
- pr_err("percpu_ida_init(): nr_tags too large\n");
- return -EINVAL;
- }
-
- order = get_order(nr_tags * sizeof(unsigned));
- pool->freelist = (void *) __get_free_pages(GFP_KERNEL, order);
- if (!pool->freelist)
- return -ENOMEM;
-
- for (i = 0; i < nr_tags; i++)
- pool->freelist[i] = i;
-
- pool->nr_free = nr_tags;
-
- pool->tag_cpu = __alloc_percpu(sizeof(struct percpu_ida_cpu) +
- pool->percpu_max_size * sizeof(unsigned),
- sizeof(unsigned));
- if (!pool->tag_cpu)
- goto err;
-
- for_each_possible_cpu(cpu)
- spin_lock_init(&per_cpu_ptr(pool->tag_cpu, cpu)->lock);
-
- return 0;
-err:
- percpu_ida_destroy(pool);
- return -ENOMEM;
-}
-EXPORT_SYMBOL_GPL(__percpu_ida_init);
-
-/**
- * percpu_ida_for_each_free - iterate free ids of a pool
- * @pool: pool to iterate
- * @fn: interate callback function
- * @data: parameter for @fn
- *
- * Note, this doesn't guarantee to iterate all free ids restrictly. Some
free
- * ids might be missed, some might be iterated duplicated, and some might
- * be iterated and not free soon.
- */
-int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
- void *data)
-{
- unsigned long flags;
- struct percpu_ida_cpu *remote;
- unsigned cpu, i, err = 0;
-
- for_each_possible_cpu(cpu) {
- remote = per_cpu_ptr(pool->tag_cpu, cpu);
- spin_lock_irqsave(&remote->lock, flags);
- for (i = 0; i < remote->nr_free; i++) {
- err = fn(remote->freelist[i], data);
- if (err)
- break;
- }
- spin_unlock_irqrestore(&remote->lock, flags);
- if (err)
- goto out;
- }
-
- spin_lock_irqsave(&pool->lock, flags);
- for (i = 0; i < pool->nr_free; i++) {
- err = fn(pool->freelist[i], data);
- if (err)
- break;
- }
- spin_unlock_irqrestore(&pool->lock, flags);
-out:
- return err;
-}
-EXPORT_SYMBOL_GPL(percpu_ida_for_each_free);
-
-/**
- * percpu_ida_free_tags - return free tags number of a specific cpu or global
pool
- * @pool: pool related
- * @cpu: specific cpu or global pool if @cpu == nr_cpu_ids
- *
- * Note: this just returns a snapshot of free tags number.
- */
-unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu)
-{
- struct percpu_ida_cpu *remote;
- if (cpu == nr_cpu_ids)
- return pool->nr_free;
- remote = per_cpu_ptr(pool->tag_cpu, cpu);
- return remote->nr_free;
-}
-EXPORT_SYMBOL_GPL(percpu_ida_free_tags);
--
2.17.1
On Tue, 2018-06-12 at 12:05 -0700, Matthew Wilcox wrote:> Removing the percpu_ida code nets over 400 lines of removal. It's not > as spectacular as deleting an entire architecture, but it's still a > worthy reduction in lines of code. > > Untested due to lack of hardware and not understanding how to set up a > target platform. > > Changes from v1: > - Fixed bugs pointed out by Jens in iscsit_wait_for_tag() > - Abstracted out tag freeing as requested by Bart > - Made iscsit_wait_for_tag static as pointed out by 0dayFor the whole series: Reviewed-by: Bart Van Assche <bart.vanassche at wdc.com> Thanks, Bart.
On 6/12/18 1:05 PM, Matthew Wilcox wrote:> Removing the percpu_ida code nets over 400 lines of removal. It's not > as spectacular as deleting an entire architecture, but it's still a > worthy reduction in lines of code. > > Untested due to lack of hardware and not understanding how to set up a > target platform. > > Changes from v1: > - Fixed bugs pointed out by Jens in iscsit_wait_for_tag() > - Abstracted out tag freeing as requested by Bart > - Made iscsit_wait_for_tag static as pointed out by 0dayReviewed-by: Jens Axboe <axboe at kernel.dk> -- Jens Axboe
Matthew,> Removing the percpu_ida code nets over 400 lines of removal. It's not > as spectacular as deleting an entire architecture, but it's still a > worthy reduction in lines of code.Since most of the changes are in scsi or target, should I take this series through my tree? -- Martin K. Petersen Oracle Linux Engineering
On Thu, Jun 14, 2018 at 10:06:58PM -0400, Martin K. Petersen wrote:> > Matthew, > > > Removing the percpu_ida code nets over 400 lines of removal. It's not > > as spectacular as deleting an entire architecture, but it's still a > > worthy reduction in lines of code. > > Since most of the changes are in scsi or target, should I take this > series through my tree?I'd welcome that. Nick seems to be inactive as target maintainer; his tree on kernel.org hasn't seen any updates in five months. Thanks!
Apparently Analagous Threads
- [PATCH 0/3] Use sbitmap instead of percpu_ida
- [PATCH 0/2] Use sbitmap instead of percpu_ida
- [PATCH-v3 0/4] target/vhost-scsi: Add per-cpu ida tag pre-allocation for v3.12
- [PATCH-v3 0/4] target/vhost-scsi: Add per-cpu ida tag pre-allocation for v3.12
- [PATCH-v2 0/3] target/vhost-scsi: Add per-cpu ida tag pre-allocation for v3.12