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author | Stefani Seibold <stefani@seibold.net> | 2009-12-21 14:37:26 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-22 14:17:55 -0800 |
commit | 45465487897a1c6d508b14b904dc5777f7ec7e04 (patch) | |
tree | 935c8dae68dc793ff2f795d57cf027531475cd53 /drivers/scsi/libiscsi_tcp.c | |
parent | 2ec91eec47f713e3d158ba5b28a24a85a2cf3650 (diff) | |
download | kernel_samsung_tuna-45465487897a1c6d508b14b904dc5777f7ec7e04.zip kernel_samsung_tuna-45465487897a1c6d508b14b904dc5777f7ec7e04.tar.gz kernel_samsung_tuna-45465487897a1c6d508b14b904dc5777f7ec7e04.tar.bz2 |
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>
Diffstat (limited to 'drivers/scsi/libiscsi_tcp.c')
-rw-r--r-- | drivers/scsi/libiscsi_tcp.c | 29 |
1 files changed, 14 insertions, 15 deletions
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 @@ 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); } } |