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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/char/sonypi.c
parent2ec91eec47f713e3d158ba5b28a24a85a2cf3650 (diff)
downloadlinux-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/char/sonypi.c')
-rw-r--r--drivers/char/sonypi.c40
1 files changed, 19 insertions, 21 deletions
diff --git a/drivers/char/sonypi.c b/drivers/char/sonypi.c
index 8c262aaf7c26..9e6efb1f029f 100644
--- a/drivers/char/sonypi.c
+++ b/drivers/char/sonypi.c
@@ -487,7 +487,7 @@ static struct sonypi_device {
int camera_power;
int bluetooth_power;
struct mutex lock;
- struct kfifo *fifo;
+ struct kfifo fifo;
spinlock_t fifo_lock;
wait_queue_head_t fifo_proc_list;
struct fasync_struct *fifo_async;
@@ -496,7 +496,7 @@ static struct sonypi_device {
struct input_dev *input_jog_dev;
struct input_dev *input_key_dev;
struct work_struct input_work;
- struct kfifo *input_fifo;
+ struct kfifo input_fifo;
spinlock_t input_fifo_lock;
} sonypi_device;
@@ -777,7 +777,7 @@ static void input_keyrelease(struct work_struct *work)
{
struct sonypi_keypress kp;
- while (kfifo_get(sonypi_device.input_fifo, (unsigned char *)&kp,
+ while (kfifo_get(&sonypi_device.input_fifo, (unsigned char *)&kp,
sizeof(kp)) == sizeof(kp)) {
msleep(10);
input_report_key(kp.dev, kp.key, 0);
@@ -827,7 +827,7 @@ static void sonypi_report_input_event(u8 event)
if (kp.dev) {
input_report_key(kp.dev, kp.key, 1);
input_sync(kp.dev);
- kfifo_put(sonypi_device.input_fifo,
+ kfifo_put(&sonypi_device.input_fifo,
(unsigned char *)&kp, sizeof(kp));
schedule_work(&sonypi_device.input_work);
}
@@ -880,7 +880,7 @@ found:
acpi_bus_generate_proc_event(sonypi_acpi_device, 1, event);
#endif
- kfifo_put(sonypi_device.fifo, (unsigned char *)&event, sizeof(event));
+ kfifo_put(&sonypi_device.fifo, (unsigned char *)&event, sizeof(event));
kill_fasync(&sonypi_device.fifo_async, SIGIO, POLL_IN);
wake_up_interruptible(&sonypi_device.fifo_proc_list);
@@ -906,7 +906,7 @@ static int sonypi_misc_open(struct inode *inode, struct file *file)
mutex_lock(&sonypi_device.lock);
/* Flush input queue on first open */
if (!sonypi_device.open_count)
- kfifo_reset(sonypi_device.fifo);
+ kfifo_reset(&sonypi_device.fifo);
sonypi_device.open_count++;
mutex_unlock(&sonypi_device.lock);
unlock_kernel();
@@ -919,17 +919,17 @@ static ssize_t sonypi_misc_read(struct file *file, char __user *buf,
ssize_t ret;
unsigned char c;
- if ((kfifo_len(sonypi_device.fifo) == 0) &&
+ if ((kfifo_len(&sonypi_device.fifo) == 0) &&
(file->f_flags & O_NONBLOCK))
return -EAGAIN;
ret = wait_event_interruptible(sonypi_device.fifo_proc_list,
- kfifo_len(sonypi_device.fifo) != 0);
+ kfifo_len(&sonypi_device.fifo) != 0);
if (ret)
return ret;
while (ret < count &&
- (kfifo_get(sonypi_device.fifo, &c, sizeof(c)) == sizeof(c))) {
+ (kfifo_get(&sonypi_device.fifo, &c, sizeof(c)) == sizeof(c))) {
if (put_user(c, buf++))
return -EFAULT;
ret++;
@@ -946,7 +946,7 @@ static ssize_t sonypi_misc_read(struct file *file, char __user *buf,
static unsigned int sonypi_misc_poll(struct file *file, poll_table *wait)
{
poll_wait(file, &sonypi_device.fifo_proc_list, wait);
- if (kfifo_len(sonypi_device.fifo))
+ if (kfifo_len(&sonypi_device.fifo))
return POLLIN | POLLRDNORM;
return 0;
}
@@ -1313,11 +1313,11 @@ static int __devinit sonypi_probe(struct platform_device *dev)
"http://www.linux.it/~malattia/wiki/index.php/Sony_drivers\n");
spin_lock_init(&sonypi_device.fifo_lock);
- sonypi_device.fifo = kfifo_alloc(SONYPI_BUF_SIZE, GFP_KERNEL,
+ error = kfifo_alloc(&sonypi_device.fifo, SONYPI_BUF_SIZE, GFP_KERNEL,
&sonypi_device.fifo_lock);
- if (IS_ERR(sonypi_device.fifo)) {
+ if (error) {
printk(KERN_ERR "sonypi: kfifo_alloc failed\n");
- return PTR_ERR(sonypi_device.fifo);
+ return error;
}
init_waitqueue_head(&sonypi_device.fifo_proc_list);
@@ -1393,12 +1393,10 @@ static int __devinit sonypi_probe(struct platform_device *dev)
}
spin_lock_init(&sonypi_device.input_fifo_lock);
- sonypi_device.input_fifo =
- kfifo_alloc(SONYPI_BUF_SIZE, GFP_KERNEL,
- &sonypi_device.input_fifo_lock);
- if (IS_ERR(sonypi_device.input_fifo)) {
+ error = kfifo_alloc(&sonypi_device.input_fifo, SONYPI_BUF_SIZE,
+ GFP_KERNEL, &sonypi_device.input_fifo_lock);
+ if (error) {
printk(KERN_ERR "sonypi: kfifo_alloc failed\n");
- error = PTR_ERR(sonypi_device.input_fifo);
goto err_inpdev_unregister;
}
@@ -1423,7 +1421,7 @@ static int __devinit sonypi_probe(struct platform_device *dev)
pci_disable_device(pcidev);
err_put_pcidev:
pci_dev_put(pcidev);
- kfifo_free(sonypi_device.fifo);
+ kfifo_free(&sonypi_device.fifo);
return error;
}
@@ -1438,7 +1436,7 @@ static int __devexit sonypi_remove(struct platform_device *dev)
if (useinput) {
input_unregister_device(sonypi_device.input_key_dev);
input_unregister_device(sonypi_device.input_jog_dev);
- kfifo_free(sonypi_device.input_fifo);
+ kfifo_free(&sonypi_device.input_fifo);
}
misc_deregister(&sonypi_misc_device);
@@ -1451,7 +1449,7 @@ static int __devexit sonypi_remove(struct platform_device *dev)
pci_dev_put(sonypi_device.dev);
}
- kfifo_free(sonypi_device.fifo);
+ kfifo_free(&sonypi_device.fifo);
return 0;
}