kfifo: move struct kfifo in place
This is a new generic kernel FIFO implementation.
The current kernel fifo API is not very widely used, because it has to
many constrains. Only 17 files in the current 2.6.31-rc5 used it.
FIFO's are like list's a very basic thing and a kfifo API which handles
the most use case would save a lot of development time and memory
resources.
I think this are the reasons why kfifo is not in use:
- The API is to simple, important functions are missing
- A fifo can be only allocated dynamically
- There is a requirement of a spinlock whether you need it or not
- There is no support for data records inside a fifo
So I decided to extend the kfifo in a more generic way without blowing up
the API to much. The new API has the following benefits:
- Generic usage: For kernel internal use and/or device driver.
- Provide an API for the most use case.
- Slim API: The whole API provides 25 functions.
- Linux style habit.
- DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros
- Direct copy_to_user from the fifo and copy_from_user into the fifo.
- The kfifo itself is an in place member of the using data structure, this save an
indirection access and does not waste the kernel allocator.
- Lockless access: if only one reader and one writer is active on the fifo,
which is the common use case, no additional locking is necessary.
- Remove spinlock - give the user the freedom of choice what kind of locking to use if
one is required.
- Ability to handle records. Three type of records are supported:
- Variable length records between 0-255 bytes, with a record size
field of 1 bytes.
- Variable length records between 0-65535 bytes, with a record size
field of 2 bytes.
- Fixed size records, which no record size field.
- Preserve memory resource.
- Performance!
- Easy to use!
This patch:
Since most users want to have the kfifo as part of another object,
reorganize the code to allow including struct kfifo in another data
structure. This requires changing the kfifo_alloc and kfifo_init
prototypes so that we pass an existing kfifo pointer into them. This
patch changes the implementation and all existing users.
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index b7689f3..cf0aa7e 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -517,7 +517,7 @@
if (conn->login_task == task)
return;
- __kfifo_put(session->cmdpool.queue, (void*)&task, sizeof(void*));
+ __kfifo_put(&session->cmdpool.queue, (void*)&task, sizeof(void*));
if (sc) {
task->sc = NULL;
@@ -737,7 +737,7 @@
BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);
- if (!__kfifo_get(session->cmdpool.queue,
+ if (!__kfifo_get(&session->cmdpool.queue,
(void*)&task, sizeof(void*)))
return NULL;
}
@@ -1567,7 +1567,7 @@
{
struct iscsi_task *task;
- if (!__kfifo_get(conn->session->cmdpool.queue,
+ if (!__kfifo_get(&conn->session->cmdpool.queue,
(void *) &task, sizeof(void *)))
return NULL;
@@ -2461,12 +2461,7 @@
if (q->pool == NULL)
return -ENOMEM;
- q->queue = kfifo_init((void*)q->pool, max * sizeof(void*),
- GFP_KERNEL, NULL);
- if (IS_ERR(q->queue)) {
- q->queue = NULL;
- goto enomem;
- }
+ kfifo_init(&q->queue, (void*)q->pool, max * sizeof(void*), NULL);
for (i = 0; i < max; i++) {
q->pool[i] = kzalloc(item_size, GFP_KERNEL);
@@ -2474,7 +2469,7 @@
q->max = i;
goto enomem;
}
- __kfifo_put(q->queue, (void*)&q->pool[i], sizeof(void*));
+ __kfifo_put(&q->queue, (void*)&q->pool[i], sizeof(void*));
}
if (items) {
@@ -2497,7 +2492,6 @@
for (i = 0; i < q->max; i++)
kfree(q->pool[i]);
kfree(q->pool);
- kfree(q->queue);
}
EXPORT_SYMBOL_GPL(iscsi_pool_free);
@@ -2825,7 +2819,7 @@
/* allocate login_task used for the login/text sequences */
spin_lock_bh(&session->lock);
- if (!__kfifo_get(session->cmdpool.queue,
+ if (!__kfifo_get(&session->cmdpool.queue,
(void*)&conn->login_task,
sizeof(void*))) {
spin_unlock_bh(&session->lock);
@@ -2845,7 +2839,7 @@
return cls_conn;
login_task_data_alloc_fail:
- __kfifo_put(session->cmdpool.queue, (void*)&conn->login_task,
+ __kfifo_put(&session->cmdpool.queue, (void*)&conn->login_task,
sizeof(void*));
login_task_alloc_fail:
iscsi_destroy_conn(cls_conn);
@@ -2908,7 +2902,7 @@
free_pages((unsigned long) conn->data,
get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
kfree(conn->persistent_address);
- __kfifo_put(session->cmdpool.queue, (void*)&conn->login_task,
+ __kfifo_put(&session->cmdpool.queue, (void*)&conn->login_task,
sizeof(void*));
if (session->leadconn == conn)
session->leadconn = NULL;
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
index ca25ee5..a83ee56 100644
--- a/drivers/scsi/libiscsi_tcp.c
+++ b/drivers/scsi/libiscsi_tcp.c
@@ -445,15 +445,15 @@
return;
/* flush task's r2t queues */
- while (__kfifo_get(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
- __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
+ while (__kfifo_get(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
+ __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
ISCSI_DBG_TCP(task->conn, "pending r2t dropped\n");
}
r2t = tcp_task->r2t;
if (r2t != NULL) {
- __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
+ __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
tcp_task->r2t = NULL;
}
@@ -541,7 +541,7 @@
return 0;
}
- rc = __kfifo_get(tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
+ rc = __kfifo_get(&tcp_task->r2tpool.queue, (void*)&r2t, sizeof(void*));
if (!rc) {
iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
"Target has sent more R2Ts than it "
@@ -554,7 +554,7 @@
if (r2t->data_length == 0) {
iscsi_conn_printk(KERN_ERR, conn,
"invalid R2T with zero data len\n");
- __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
+ __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
return ISCSI_ERR_DATALEN;
}
@@ -570,7 +570,7 @@
"invalid R2T with data len %u at offset %u "
"and total length %d\n", r2t->data_length,
r2t->data_offset, scsi_out(task->sc)->length);
- __kfifo_put(tcp_task->r2tpool.queue, (void*)&r2t,
+ __kfifo_put(&tcp_task->r2tpool.queue, (void*)&r2t,
sizeof(void*));
return ISCSI_ERR_DATALEN;
}
@@ -580,7 +580,7 @@
r2t->sent = 0;
tcp_task->exp_datasn = r2tsn + 1;
- __kfifo_put(tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
+ __kfifo_put(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
conn->r2t_pdus_cnt++;
iscsi_requeue_task(task);
@@ -951,7 +951,7 @@
return conn->session->tt->init_pdu(task, 0, task->data_count);
}
- BUG_ON(__kfifo_len(tcp_task->r2tqueue));
+ BUG_ON(__kfifo_len(&tcp_task->r2tqueue));
tcp_task->exp_datasn = 0;
/* Prepare PDU, optionally w/ immediate data */
@@ -982,7 +982,7 @@
if (r2t->data_length <= r2t->sent) {
ISCSI_DBG_TCP(task->conn,
" done with r2t %p\n", r2t);
- __kfifo_put(tcp_task->r2tpool.queue,
+ __kfifo_put(&tcp_task->r2tpool.queue,
(void *)&tcp_task->r2t,
sizeof(void *));
tcp_task->r2t = r2t = NULL;
@@ -990,7 +990,7 @@
}
if (r2t == NULL) {
- __kfifo_get(tcp_task->r2tqueue,
+ __kfifo_get(&tcp_task->r2tqueue,
(void *)&tcp_task->r2t, sizeof(void *));
r2t = tcp_task->r2t;
}
@@ -1127,9 +1127,8 @@
}
/* R2T xmit queue */
- tcp_task->r2tqueue = kfifo_alloc(
- session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
- if (tcp_task->r2tqueue == ERR_PTR(-ENOMEM)) {
+ if (kfifo_alloc(&tcp_task->r2tqueue,
+ session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL)) {
iscsi_pool_free(&tcp_task->r2tpool);
goto r2t_alloc_fail;
}
@@ -1142,7 +1141,7 @@
struct iscsi_task *task = session->cmds[i];
struct iscsi_tcp_task *tcp_task = task->dd_data;
- kfifo_free(tcp_task->r2tqueue);
+ kfifo_free(&tcp_task->r2tqueue);
iscsi_pool_free(&tcp_task->r2tpool);
}
return -ENOMEM;
@@ -1157,7 +1156,7 @@
struct iscsi_task *task = session->cmds[i];
struct iscsi_tcp_task *tcp_task = task->dd_data;
- kfifo_free(tcp_task->r2tqueue);
+ kfifo_free(&tcp_task->r2tqueue);
iscsi_pool_free(&tcp_task->r2tpool);
}
}
diff --git a/drivers/scsi/libsrp.c b/drivers/scsi/libsrp.c
index 9ad38e8..b1b5e51 100644
--- a/drivers/scsi/libsrp.c
+++ b/drivers/scsi/libsrp.c
@@ -58,19 +58,16 @@
goto free_pool;
spin_lock_init(&q->lock);
- q->queue = kfifo_init((void *) q->pool, max * sizeof(void *),
- GFP_KERNEL, &q->lock);
- if (IS_ERR(q->queue))
- goto free_item;
+ kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *),
+ &q->lock);
for (i = 0, iue = q->items; i < max; i++) {
- __kfifo_put(q->queue, (void *) &iue, sizeof(void *));
+ __kfifo_put(&q->queue, (void *) &iue, sizeof(void *));
iue->sbuf = ring[i];
iue++;
}
return 0;
-free_item:
kfree(q->items);
free_pool:
kfree(q->pool);
@@ -167,7 +164,7 @@
{
struct iu_entry *iue = NULL;
- kfifo_get(target->iu_queue.queue, (void *) &iue, sizeof(void *));
+ kfifo_get(&target->iu_queue.queue, (void *) &iue, sizeof(void *));
if (!iue)
return iue;
iue->target = target;
@@ -179,7 +176,7 @@
void srp_iu_put(struct iu_entry *iue)
{
- kfifo_put(iue->target->iu_queue.queue, (void *) &iue, sizeof(void *));
+ kfifo_put(&iue->target->iu_queue.queue, (void *) &iue, sizeof(void *));
}
EXPORT_SYMBOL_GPL(srp_iu_put);