From 45465487897a1c6d508b14b904dc5777f7ec7e04 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:26 -0800 Subject: 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 Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/sonypi.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-) (limited to 'drivers/char/sonypi.c') diff --git a/drivers/char/sonypi.c b/drivers/char/sonypi.c index 8c262aaf7c2..9e6efb1f029 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; } -- cgit v1.2.3