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kfifo: move struct kfifo in place

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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.

[[email protected]: fix warning]
Signed-off-by: Stefani Seibold <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Andi Kleen <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Stefani Seibold 2009-12-21 14:37:26 -08:00 • committed by Linus Torvalds
commit 4546548789
24 changed files with 238 additions and 259 deletions
Download patch file Download diff file Expand all files Collapse all files

22
drivers/scsi/libiscsi.c
View file

@ -517,7 +517,7 @@ static void iscsi_free_task(struct iscsi_task *task)
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 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
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 @@ static inline struct iscsi_task *iscsi_alloc_task(struct iscsi_conn *conn,
{
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 @@ iscsi_pool_init(struct iscsi_pool *q, int max, void ***items, int item_size)
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 @@ iscsi_pool_init(struct iscsi_pool *q, int max, void ***items, int item_size)
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 @@ void iscsi_pool_free(struct iscsi_pool *q)
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 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
/* 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 @@ iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
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 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
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;

29
drivers/scsi/libiscsi_tcp.c
View file

@ -445,15 +445,15 @@ void iscsi_tcp_cleanup_task(struct iscsi_task *task)
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 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
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 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
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 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
"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 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
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 @@ int iscsi_tcp_task_init(struct iscsi_task *task)
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 @@ static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
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 @@ static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
}
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 @@ int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
}
/* 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 @@ r2t_alloc_fail:
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 @@ void iscsi_tcp_r2tpool_free(struct iscsi_session *session)
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);
}
}

13
drivers/scsi/libsrp.c
View file

@ -58,19 +58,16 @@ static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
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 *srp_iu_get(struct srp_target *target)
{
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 @@ EXPORT_SYMBOL_GPL(srp_iu_get);
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);