From: Matthew Wilcox <[email protected]>
This is a pretty rough-and-ready conversion of the target drivers
from using percpu_ida to sbitmap. It compiles; I don't have a target
setup, so it's completely untested. I haven't tried to do anything
particularly clever here, so it's possible that, for example, the wait
queue in iscsi_target_util could be more clever, like the block layer
uses multiple wait queues to avoid pingpongs. Or maybe we could figure
out a way to not store the CPU that the ID was allocated on, or perhaps
the options I specified to sbitmap_queue_init() are suboptimal.
Patch 2 isn't interesting; it just deletes the implementation. Patch 1
will be where all the action is.
Matthew Wilcox (2):
Convert target drivers to use sbitmap
Remove percpu_ida
drivers/scsi/qla2xxx/qla_target.c | 16 +-
drivers/target/iscsi/iscsi_target_util.c | 34 +-
drivers/target/sbp/sbp_target.c | 8 +-
drivers/target/target_core_transport.c | 5 +-
drivers/target/tcm_fc/tfc_cmd.c | 11 +-
drivers/usb/gadget/function/f_tcm.c | 8 +-
drivers/vhost/scsi.c | 9 +-
drivers/xen/xen-scsiback.c | 8 +-
include/linux/percpu_ida.h | 83 -----
include/target/iscsi/iscsi_target_core.h | 1 +
include/target/target_core_base.h | 5 +-
lib/Makefile | 2 +-
lib/percpu_ida.c | 391 -----------------------
13 files changed, 74 insertions(+), 507 deletions(-)
delete mode 100644 include/linux/percpu_ida.h
delete mode 100644 lib/percpu_ida.c
--
2.17.0
From: Matthew Wilcox <[email protected]>
With its one user gone, remove the library code.
Signed-off-by: Matthew Wilcox <[email protected]>
---
include/linux/percpu_ida.h | 83 --------
lib/Makefile | 2 +-
lib/percpu_ida.c | 391 -------------------------------------
3 files changed, 1 insertion(+), 475 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 ce20696d5a92..7626dece1d27 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -39,7 +39,7 @@ 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 6016f1deb1f5..000000000000
--- a/lib/percpu_ida.c
+++ /dev/null
@@ -1,391 +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));
-}
-
-static inline unsigned alloc_local_tag(struct percpu_ida_cpu *tags)
-{
- int tag = -ENOSPC;
-
- spin_lock(&tags->lock);
- if (tags->nr_free)
- tag = tags->freelist[--tags->nr_free];
- spin_unlock(&tags->lock);
-
- return tag;
-}
-
-/**
- * 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;
-
- local_irq_save(flags);
- tags = this_cpu_ptr(pool->tag_cpu);
-
- /* Fastpath */
- tag = alloc_local_tag(tags);
- if (likely(tag >= 0)) {
- local_irq_restore(flags);
- return tag;
- }
-
- while (1) {
- spin_lock(&pool->lock);
-
- /*
- * 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(&pool->lock);
- local_irq_restore(flags);
-
- if (tag >= 0 || state == TASK_RUNNING)
- break;
-
- if (signal_pending_state(state, current)) {
- tag = -ERESTARTSYS;
- break;
- }
-
- schedule();
-
- local_irq_save(flags);
- tags = this_cpu_ptr(pool->tag_cpu);
- }
- 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);
-
- local_irq_save(flags);
- tags = this_cpu_ptr(pool->tag_cpu);
-
- spin_lock(&tags->lock);
- tags->freelist[tags->nr_free++] = tag;
-
- nr_free = tags->nr_free;
- spin_unlock(&tags->lock);
-
- if (nr_free == 1) {
- cpumask_set_cpu(smp_processor_id(),
- &pool->cpus_have_tags);
- wake_up(&pool->wait);
- }
-
- if (nr_free == pool->percpu_max_size) {
- spin_lock(&pool->lock);
-
- /*
- * Global lock held and irqs disabled, don't need percpu
- * 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(&pool->lock);
- }
-
- local_irq_restore(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;
-
- local_irq_save(flags);
- for_each_possible_cpu(cpu) {
- remote = per_cpu_ptr(pool->tag_cpu, cpu);
- spin_lock(&remote->lock);
- for (i = 0; i < remote->nr_free; i++) {
- err = fn(remote->freelist[i], data);
- if (err)
- break;
- }
- spin_unlock(&remote->lock);
- if (err)
- goto out;
- }
-
- spin_lock(&pool->lock);
- for (i = 0; i < pool->nr_free; i++) {
- err = fn(pool->freelist[i], data);
- if (err)
- break;
- }
- spin_unlock(&pool->lock);
-out:
- local_irq_restore(flags);
- 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);
--
2.17.0
From: Matthew Wilcox <[email protected]>
The sbitmap and the percpu_ida perform essentially the same task,
allocating tags for commands. Since the sbitmap is more used than
the percpu_ida, convert the percpu_ida users to the sbitmap API.
Signed-off-by: Matthew Wilcox <[email protected]>
---
drivers/scsi/qla2xxx/qla_target.c | 16 ++++++-----
drivers/target/iscsi/iscsi_target_util.c | 34 +++++++++++++++++++++---
drivers/target/sbp/sbp_target.c | 8 +++---
drivers/target/target_core_transport.c | 5 ++--
drivers/target/tcm_fc/tfc_cmd.c | 11 ++++----
drivers/usb/gadget/function/f_tcm.c | 8 +++---
drivers/vhost/scsi.c | 9 ++++---
drivers/xen/xen-scsiback.c | 8 +++---
include/target/iscsi/iscsi_target_core.h | 1 +
include/target/target_core_base.h | 5 ++--
10 files changed, 73 insertions(+), 32 deletions(-)
diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
index 025dc2d3f3de..cdf671c2af61 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -3719,7 +3719,8 @@ 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);
+ sbitmap_queue_clear(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag,
+ cmd->se_cmd.map_cpu);
}
EXPORT_SYMBOL(qlt_free_cmd);
@@ -4084,7 +4085,8 @@ 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);
+ sbitmap_queue_clear(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag,
+ cmd->se_cmd.map_cpu);
spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
spin_lock_irqsave(&ha->tgt.sess_lock, flags);
@@ -4215,9 +4217,9 @@ 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;
@@ -4230,6 +4232,7 @@ 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;
@@ -5212,7 +5215,7 @@ 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)) {
@@ -5244,7 +5247,7 @@ 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;
@@ -5275,6 +5278,7 @@ 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 4435bf374d2d..28bcffae609f 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 +147,28 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
spin_unlock_bh(&cmd->r2t_lock);
}
+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;
+ schedule();
+ tag = sbitmap_queue_get(&se_sess->sess_tag_pool, cpup);
+ }
+
+ finish_wait(&ws->wait, &wait);
+ return tag;
+}
+
/*
* May be called from software interrupt (timer) context for allocating
* iSCSI NopINs.
@@ -155,9 +177,11 @@ 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 +190,7 @@ 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);
@@ -711,7 +736,8 @@ 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);
+ sbitmap_queue_clear(&sess->se_sess->sess_tag_pool, se_cmd->map_tag,
+ se_cmd->map_cpu);
}
EXPORT_SYMBOL(iscsit_release_cmd);
diff --git a/drivers/target/sbp/sbp_target.c b/drivers/target/sbp/sbp_target.c
index fb1003921d85..c58f9f04c6be 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;
@@ -1460,7 +1461,8 @@ 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);
+ sbitmap_queue_clear(&se_sess->sess_tag_pool, se_cmd->map_tag,
+ se_cmd->map_cpu);
}
static void sbp_mgt_agent_process(struct work_struct *work)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 4558f2e1fe1b..3103890ed109 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 ec372860106f..b3e3364b7147 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>
@@ -92,7 +91,8 @@ 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);
+ sbitmap_queue_clear(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag,
+ cmd->se_cmd.map_cpu);
ft_sess_put(sess); /* undo get from lookup at recv */
}
@@ -448,9 +448,9 @@ 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;
@@ -458,10 +458,11 @@ 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) {
- percpu_ida_free(&se_sess->sess_tag_pool, tag);
+ sbitmap_queue_clear(&se_sess->sess_tag_pool, tag, cpu);
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..b335f4f33bc3 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;
@@ -1288,7 +1289,8 @@ 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);
+ sbitmap_queue_clear(&se_sess->sess_tag_pool, se_cmd->map_tag,
+ se_cmd->map_cpu);
}
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..1fadaa39f322 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"
@@ -324,7 +323,8 @@ 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);
+ sbitmap_queue_clear(&se_sess->sess_tag_pool, se_cmd->map_tag,
+ se_cmd->map_cpu);
}
static u32 vhost_scsi_sess_get_index(struct se_session *se_sess)
@@ -567,7 +567,7 @@ 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 +576,7 @@ 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 +591,7 @@ 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 7bc88fd43cfc..d2c71b8608f0 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;
@@ -1379,7 +1380,8 @@ 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);
+ sbitmap_queue_clear(&se_sess->sess_tag_pool, se_cmd->map_tag,
+ se_cmd->map_cpu);
}
static u32 scsiback_sess_get_index(struct se_session *se_sess)
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 9f9f5902af38..cd417b17fee6 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>
@@ -454,6 +454,7 @@ 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 */
@@ -607,7 +608,7 @@ 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;
--
2.17.0
On 5/15/18 10:00 AM, Matthew Wilcox wrote:
> From: Matthew Wilcox <[email protected]>
>
> The sbitmap and the percpu_ida perform essentially the same task,
> allocating tags for commands. Since the sbitmap is more used than
> the percpu_ida, convert the percpu_ida users to the sbitmap API.
It should also be the same performance as percpu_ida in light use, and
performs much better at > 50% utilization of the tag space. I think
that's better justification than "more used than".
> diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
> index 4435bf374d2d..28bcffae609f 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 +147,28 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
> spin_unlock_bh(&cmd->r2t_lock);
> }
>
> +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;
> + schedule();
> + tag = sbitmap_queue_get(&se_sess->sess_tag_pool, cpup);
> + }
> +
> + finish_wait(&ws->wait, &wait);
> + return tag;
> +}
Seems like that should be:
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 != -1)
break;
schedule();
}
finish_wait(&ws->wait, &wait);
return tag;
> /*
> * May be called from software interrupt (timer) context for allocating
> * iSCSI NopINs.
> @@ -155,9 +177,11 @@ 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;
Might make sense to just roll the whole thing into iscsi_get_tag(), that
would be cleaner.
sbitmap should provide a helper for that, but we can do that cleanup
later. That would encapsulate things like the per-cpu caching hint too,
for instance.
Rest looks fine to me.
--
Jens Axboe
On 5/15/18 10:11 AM, Jens Axboe wrote:
> On 5/15/18 10:00 AM, Matthew Wilcox wrote:
>> From: Matthew Wilcox <[email protected]>
>>
>> The sbitmap and the percpu_ida perform essentially the same task,
>> allocating tags for commands. Since the sbitmap is more used than
>> the percpu_ida, convert the percpu_ida users to the sbitmap API.
>
> It should also be the same performance as percpu_ida in light use, and
> performs much better at > 50% utilization of the tag space. I think
> that's better justification than "more used than".
Had to search long and hard for the perf numbers I did for percpu_ida
on higher utilization, but here it is:
https://lkml.org/lkml/2014/4/22/553
--
Jens Axboe
Hi,
Matthew Wilcox <[email protected]> writes:
> From: Matthew Wilcox <[email protected]>
>
> The sbitmap and the percpu_ida perform essentially the same task,
> allocating tags for commands. Since the sbitmap is more used than
> the percpu_ida, convert the percpu_ida users to the sbitmap API.
>
> Signed-off-by: Matthew Wilcox <[email protected]>
> ---
[...]
> drivers/usb/gadget/function/f_tcm.c | 8 +++---
for drivers/usb/gadget/function/f_tcm.c
Acked-by: Felipe Balbi <[email protected]>
--
balbi
Hi Matthew,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v4.17-rc5 next-20180516]
[cannot apply to target/master]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Matthew-Wilcox/Use-sbitmap-instead-of-percpu_ida/20180516-143658
reproduce:
# apt-get install sparse
make ARCH=x86_64 allmodconfig
make C=1 CF=-D__CHECK_ENDIAN__
sparse warnings: (new ones prefixed by >>)
>> drivers/target/iscsi/iscsi_target_util.c:150:5: sparse: symbol 'iscsit_wait_for_tag' was not declared. Should it be static?
drivers/target/iscsi/iscsi_target_util.c:1174:31: sparse: expression using sizeof(void)
drivers/target/iscsi/iscsi_target_util.c:1174:31: sparse: expression using sizeof(void)
Please review and possibly fold the followup patch.
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Fixes: 5aff7a710f13 ("Convert target drivers to use sbitmap")
Signed-off-by: Fengguang Wu <[email protected]>
---
iscsi_target_util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 28bcffa..e147aef 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -147,7 +147,7 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
spin_unlock_bh(&cmd->r2t_lock);
}
-int iscsit_wait_for_tag(struct se_session *se_sess, int state, int *cpup)
+static int iscsit_wait_for_tag(struct se_session *se_sess, int state, int *cpup)
{
int tag = -1;
DEFINE_WAIT(wait);
On 5/15/18 10:11 AM, Jens Axboe wrote:
> On 5/15/18 10:00 AM, Matthew Wilcox wrote:
>> From: Matthew Wilcox <[email protected]>
>>
>> The sbitmap and the percpu_ida perform essentially the same task,
>> allocating tags for commands. Since the sbitmap is more used than
>> the percpu_ida, convert the percpu_ida users to the sbitmap API.
>
> It should also be the same performance as percpu_ida in light use, and
> performs much better at > 50% utilization of the tag space. I think
> that's better justification than "more used than".
>
>> diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
>> index 4435bf374d2d..28bcffae609f 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 +147,28 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
>> spin_unlock_bh(&cmd->r2t_lock);
>> }
>>
>> +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;
>> + schedule();
>> + tag = sbitmap_queue_get(&se_sess->sess_tag_pool, cpup);
>> + }
>> +
>> + finish_wait(&ws->wait, &wait);
>> + return tag;
>> +}
>
> Seems like that should be:
>
>
> 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 != -1)
> break;
> schedule();
> }
>
> finish_wait(&ws->wait, &wait);
> return tag;
>
>> /*
>> * May be called from software interrupt (timer) context for allocating
>> * iSCSI NopINs.
>> @@ -155,9 +177,11 @@ 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;
>
> Might make sense to just roll the whole thing into iscsi_get_tag(), that
> would be cleaner.
>
> sbitmap should provide a helper for that, but we can do that cleanup
> later. That would encapsulate things like the per-cpu caching hint too,
> for instance.
>
> Rest looks fine to me.
Are you going to push this further? I really think we should.
--
Jens Axboe
On Mon, Jun 11, 2018 at 07:18:55PM -0600, Jens Axboe wrote:
> Are you going to push this further? I really think we should.
Yes, I'll resubmit it tomorrow. Sorry for dropping the ball on this one.
On Tue, 2018-05-15 at 09:00 -0700, Matthew Wilcox wrote:
> diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
> index 025dc2d3f3de..cdf671c2af61 100644
> --- a/drivers/scsi/qla2xxx/qla_target.c
> +++ b/drivers/scsi/qla2xxx/qla_target.c
> @@ -3719,7 +3719,8 @@ 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);
> + sbitmap_queue_clear(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag,
> + cmd->se_cmd.map_cpu);
> }
> EXPORT_SYMBOL(qlt_free_cmd);
Please introduce functions in the target core for allocating and freeing a tag
instead of spreading the knowledge of how to allocate and free tags over all
target drivers.
> +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;
This looks weird to me. Shouldn't target code ignore signals instead of causing
tag allocation to fail if a signal is received?
> + schedule();
> + tag = sbitmap_queue_get(&se_sess->sess_tag_pool, cpup);
> + }
> +
> + finish_wait(&ws->wait, &wait);
> + return tag;
> +}
Thanks,
Bart.
On Tue, Jun 12, 2018 at 03:22:42PM +0000, Bart Van Assche wrote:
> On Tue, 2018-05-15 at 09:00 -0700, Matthew Wilcox wrote:
> > diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
> > index 025dc2d3f3de..cdf671c2af61 100644
> > --- a/drivers/scsi/qla2xxx/qla_target.c
> > +++ b/drivers/scsi/qla2xxx/qla_target.c
> > @@ -3719,7 +3719,8 @@ 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);
> > + sbitmap_queue_clear(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag,
> > + cmd->se_cmd.map_cpu);
> > }
> > EXPORT_SYMBOL(qlt_free_cmd);
>
> Please introduce functions in the target core for allocating and freeing a tag
> instead of spreading the knowledge of how to allocate and free tags over all
> target drivers.
I can't without doing an unreasonably large amount of work on drivers that
I have no way to test. Some of the drivers have the se_cmd already; some
of them don't. I'd be happy to introduce a common function for freeing
a tag.
> > +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;
>
> This looks weird to me. Shouldn't target code ignore signals instead of causing
> tag allocation to fail if a signal is received?
It's what the current code did:
- if (signal_pending_state(state, current)) {
- tag = -ERESTARTSYS;
- break;
- }
and the current callers literally indicate that they want signals:
drivers/infiniband/ulp/isert/ib_isert.c: cmd = iscsit_allocate_cmd(conn, TASK_INTERRUPTIBLE);
drivers/target/iscsi/iscsi_target.c: cmd = iscsit_allocate_cmd(conn, TASK_INTERRUPTIBLE);
(etc)
On Tue, 2018-06-12 at 09:15 -0700, Matthew Wilcox wrote:
> On Tue, Jun 12, 2018 at 03:22:42PM +0000, Bart Van Assche wrote:
> > On Tue, 2018-05-15 at 09:00 -0700, Matthew Wilcox wrote:
> > > diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
> > > index 025dc2d3f3de..cdf671c2af61 100644
> > > --- a/drivers/scsi/qla2xxx/qla_target.c
> > > +++ b/drivers/scsi/qla2xxx/qla_target.c
> > > @@ -3719,7 +3719,8 @@ 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);
> > > + sbitmap_queue_clear(&sess->se_sess->sess_tag_pool, cmd->se_cmd.map_tag,
> > > + cmd->se_cmd.map_cpu);
> > > }
> > > EXPORT_SYMBOL(qlt_free_cmd);
> >
> > Please introduce functions in the target core for allocating and freeing a tag
> > instead of spreading the knowledge of how to allocate and free tags over all
> > target drivers.
>
> I can't without doing an unreasonably large amount of work on drivers that
> I have no way to test. Some of the drivers have the se_cmd already; some
> of them don't. I'd be happy to introduce a common function for freeing
> a tag.
Which target drivers are you referring to? If you are referring to the sbp driver:
I think that driver is dead and can be removed from the kernel tree. I even don't
know whether that driver ever has had any users other than the developer of that
driver.
> > This looks weird to me. Shouldn't target code ignore signals instead of causing
> > tag allocation to fail if a signal is received?
>
> It's what the current code did:
>
> - if (signal_pending_state(state, current)) {
> - tag = -ERESTARTSYS;
> - break;
> - }
>
> and the current callers literally indicate that they want signals:
>
> drivers/infiniband/ulp/isert/ib_isert.c: cmd = iscsit_allocate_cmd(conn, TASK_INTERRUPTIBLE);
> drivers/target/iscsi/iscsi_target.c: cmd = iscsit_allocate_cmd(conn, TASK_INTERRUPTIBLE);
Right, the iSCSI target driver uses signals to wake up threads (see also the
send_sig() calls in the iSCSI target code).
Bart.
On Tue, Jun 12, 2018 at 04:32:03PM +0000, Bart Van Assche wrote:
> On Tue, 2018-06-12 at 09:15 -0700, Matthew Wilcox wrote:
> > On Tue, Jun 12, 2018 at 03:22:42PM +0000, Bart Van Assche wrote:
> > > Please introduce functions in the target core for allocating and freeing a tag
> > > instead of spreading the knowledge of how to allocate and free tags over all
> > > target drivers.
> >
> > I can't without doing an unreasonably large amount of work on drivers that
> > I have no way to test. Some of the drivers have the se_cmd already; some
> > of them don't. I'd be happy to introduce a common function for freeing
> > a tag.
>
> Which target drivers are you referring to? If you are referring to the sbp driver:
> I think that driver is dead and can be removed from the kernel tree. I even don't
> know whether that driver ever has had any users other than the developer of that
> driver.
For example tcm_fc:
tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0)
goto busy;
cmd = &((struct ft_cmd *)se_sess->sess_cmd_map)[tag];
or qla2xxx:
tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
if (tag < 0)
return NULL;
cmd = &((struct qla_tgt_cmd *)se_sess->sess_cmd_map)[tag];
The core doesn't know at what offset from the pointer to store the tag
& cpu. Only the individual drivers know their cmd layout.