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authorStefani Seibold <stefani@seibold.net>2009-12-21 14:37:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-22 14:17:55 -0800
commit45465487897a1c6d508b14b904dc5777f7ec7e04 (patch)
tree935c8dae68dc793ff2f795d57cf027531475cd53 /drivers/platform/x86/fujitsu-laptop.c
parent2ec91eec47f713e3d158ba5b28a24a85a2cf3650 (diff)
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/platform/x86/fujitsu-laptop.c')
-rw-r--r--drivers/platform/x86/fujitsu-laptop.c18
1 files changed, 8 insertions, 10 deletions
diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index bcd4ba8be7db..f999fba0e25e 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -164,7 +164,7 @@ struct fujitsu_hotkey_t {
struct input_dev *input;
char phys[32];
struct platform_device *pf_device;
- struct kfifo *fifo;
+ struct kfifo fifo;
spinlock_t fifo_lock;
int rfkill_supported;
int rfkill_state;
@@ -824,12 +824,10 @@ static int acpi_fujitsu_hotkey_add(struct acpi_device *device)
/* kfifo */
spin_lock_init(&fujitsu_hotkey->fifo_lock);
- fujitsu_hotkey->fifo =
- kfifo_alloc(RINGBUFFERSIZE * sizeof(int), GFP_KERNEL,
- &fujitsu_hotkey->fifo_lock);
- if (IS_ERR(fujitsu_hotkey->fifo)) {
+ error = kfifo_alloc(&fujitsu_hotkey->fifo, RINGBUFFERSIZE * sizeof(int),
+ GFP_KERNEL, &fujitsu_hotkey->fifo_lock);
+ if (error) {
printk(KERN_ERR "kfifo_alloc failed\n");
- error = PTR_ERR(fujitsu_hotkey->fifo);
goto err_stop;
}
@@ -934,7 +932,7 @@ err_unregister_input_dev:
err_free_input_dev:
input_free_device(input);
err_free_fifo:
- kfifo_free(fujitsu_hotkey->fifo);
+ kfifo_free(&fujitsu_hotkey->fifo);
err_stop:
return result;
}
@@ -956,7 +954,7 @@ static int acpi_fujitsu_hotkey_remove(struct acpi_device *device, int type)
input_free_device(input);
- kfifo_free(fujitsu_hotkey->fifo);
+ kfifo_free(&fujitsu_hotkey->fifo);
fujitsu_hotkey->acpi_handle = NULL;
@@ -1008,7 +1006,7 @@ static void acpi_fujitsu_hotkey_notify(struct acpi_device *device, u32 event)
vdbg_printk(FUJLAPTOP_DBG_TRACE,
"Push keycode into ringbuffer [%d]\n",
keycode);
- status = kfifo_put(fujitsu_hotkey->fifo,
+ status = kfifo_put(&fujitsu_hotkey->fifo,
(unsigned char *)&keycode,
sizeof(keycode));
if (status != sizeof(keycode)) {
@@ -1022,7 +1020,7 @@ static void acpi_fujitsu_hotkey_notify(struct acpi_device *device, u32 event)
} else if (keycode == 0) {
while ((status =
kfifo_get
- (fujitsu_hotkey->fifo, (unsigned char *)
+ (&fujitsu_hotkey->fifo, (unsigned char *)
&keycode_r,
sizeof
(keycode_r))) == sizeof(keycode_r)) {