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/net/wireless/libertas/cmd.c b/drivers/net/wireless/libertas/cmd.c
index b9b371b..ffed17f 100644
--- a/drivers/net/wireless/libertas/cmd.c
+++ b/drivers/net/wireless/libertas/cmd.c
@@ -1365,7 +1365,7 @@
priv->dnld_sent = DNLD_RES_RECEIVED;
/* If nothing to do, go back to sleep (?) */
- if (!__kfifo_len(priv->event_fifo) && !priv->resp_len[priv->resp_idx])
+ if (!__kfifo_len(&priv->event_fifo) && !priv->resp_len[priv->resp_idx])
priv->psstate = PS_STATE_SLEEP;
spin_unlock_irqrestore(&priv->driver_lock, flags);
@@ -1439,7 +1439,7 @@
}
/* Pending events or command responses? */
- if (__kfifo_len(priv->event_fifo) || priv->resp_len[priv->resp_idx]) {
+ if (__kfifo_len(&priv->event_fifo) || priv->resp_len[priv->resp_idx]) {
allowed = 0;
lbs_deb_host("pending events or command responses\n");
}
diff --git a/drivers/net/wireless/libertas/dev.h b/drivers/net/wireless/libertas/dev.h
index 6a8d2b2..05bb298 100644
--- a/drivers/net/wireless/libertas/dev.h
+++ b/drivers/net/wireless/libertas/dev.h
@@ -10,7 +10,7 @@
#include "scan.h"
#include "assoc.h"
-
+#include <linux/kfifo.h>
/** sleep_params */
struct sleep_params {
@@ -120,7 +120,7 @@
u32 resp_len[2];
/* Events sent from hardware to driver */
- struct kfifo *event_fifo;
+ struct kfifo event_fifo;
/** thread to service interrupts */
struct task_struct *main_thread;
diff --git a/drivers/net/wireless/libertas/main.c b/drivers/net/wireless/libertas/main.c
index db38a5a..4039092 100644
--- a/drivers/net/wireless/libertas/main.c
+++ b/drivers/net/wireless/libertas/main.c
@@ -459,7 +459,7 @@
else if (!list_empty(&priv->cmdpendingq) &&
!(priv->wakeup_dev_required))
shouldsleep = 0; /* We have a command to send */
- else if (__kfifo_len(priv->event_fifo))
+ else if (__kfifo_len(&priv->event_fifo))
shouldsleep = 0; /* We have an event to process */
else
shouldsleep = 1; /* No command */
@@ -511,9 +511,9 @@
/* Process hardware events, e.g. card removed, link lost */
spin_lock_irq(&priv->driver_lock);
- while (__kfifo_len(priv->event_fifo)) {
+ while (__kfifo_len(&priv->event_fifo)) {
u32 event;
- __kfifo_get(priv->event_fifo, (unsigned char *) &event,
+ __kfifo_get(&priv->event_fifo, (unsigned char *) &event,
sizeof(event));
spin_unlock_irq(&priv->driver_lock);
lbs_process_event(priv, event);
@@ -883,10 +883,9 @@
priv->resp_len[0] = priv->resp_len[1] = 0;
/* Create the event FIFO */
- priv->event_fifo = kfifo_alloc(sizeof(u32) * 16, GFP_KERNEL, NULL);
- if (IS_ERR(priv->event_fifo)) {
+ ret = kfifo_alloc(&priv->event_fifo, sizeof(u32) * 16, GFP_KERNEL, NULL);
+ if (ret) {
lbs_pr_err("Out of memory allocating event FIFO buffer\n");
- ret = -ENOMEM;
goto out;
}
@@ -901,8 +900,7 @@
lbs_deb_enter(LBS_DEB_MAIN);
lbs_free_cmd_buffer(priv);
- if (priv->event_fifo)
- kfifo_free(priv->event_fifo);
+ kfifo_free(&priv->event_fifo);
del_timer(&priv->command_timer);
del_timer(&priv->auto_deepsleep_timer);
kfree(priv->networks);
@@ -1177,7 +1175,7 @@
if (priv->psstate == PS_STATE_SLEEP)
priv->psstate = PS_STATE_AWAKE;
- __kfifo_put(priv->event_fifo, (unsigned char *) &event, sizeof(u32));
+ __kfifo_put(&priv->event_fifo, (unsigned char *) &event, sizeof(u32));
wake_up_interruptible(&priv->waitq);