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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/media/video/meye.c | |
parent | 2ec91eec47f713e3d158ba5b28a24a85a2cf3650 (diff) | |
download | blackbird-obmc-linux-45465487897a1c6d508b14b904dc5777f7ec7e04.tar.gz blackbird-obmc-linux-45465487897a1c6d508b14b904dc5777f7ec7e04.zip |
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/media/video/meye.c')
-rw-r--r-- | drivers/media/video/meye.c | 48 |
1 files changed, 23 insertions, 25 deletions
diff --git a/drivers/media/video/meye.c b/drivers/media/video/meye.c index 6ffa64cd1c6d..dacbbb839b9e 100644 --- a/drivers/media/video/meye.c +++ b/drivers/media/video/meye.c @@ -800,7 +800,7 @@ again: return IRQ_HANDLED; if (meye.mchip_mode == MCHIP_HIC_MODE_CONT_OUT) { - if (kfifo_get(meye.grabq, (unsigned char *)&reqnr, + if (kfifo_get(&meye.grabq, (unsigned char *)&reqnr, sizeof(int)) != sizeof(int)) { mchip_free_frame(); return IRQ_HANDLED; @@ -811,7 +811,7 @@ again: meye.grab_buffer[reqnr].state = MEYE_BUF_DONE; do_gettimeofday(&meye.grab_buffer[reqnr].timestamp); meye.grab_buffer[reqnr].sequence = sequence++; - kfifo_put(meye.doneq, (unsigned char *)&reqnr, sizeof(int)); + kfifo_put(&meye.doneq, (unsigned char *)&reqnr, sizeof(int)); wake_up_interruptible(&meye.proc_list); } else { int size; @@ -820,7 +820,7 @@ again: mchip_free_frame(); goto again; } - if (kfifo_get(meye.grabq, (unsigned char *)&reqnr, + if (kfifo_get(&meye.grabq, (unsigned char *)&reqnr, sizeof(int)) != sizeof(int)) { mchip_free_frame(); goto again; @@ -831,7 +831,7 @@ again: meye.grab_buffer[reqnr].state = MEYE_BUF_DONE; do_gettimeofday(&meye.grab_buffer[reqnr].timestamp); meye.grab_buffer[reqnr].sequence = sequence++; - kfifo_put(meye.doneq, (unsigned char *)&reqnr, sizeof(int)); + kfifo_put(&meye.doneq, (unsigned char *)&reqnr, sizeof(int)); wake_up_interruptible(&meye.proc_list); } mchip_free_frame(); @@ -859,8 +859,8 @@ static int meye_open(struct file *file) for (i = 0; i < MEYE_MAX_BUFNBRS; i++) meye.grab_buffer[i].state = MEYE_BUF_UNUSED; - kfifo_reset(meye.grabq); - kfifo_reset(meye.doneq); + kfifo_reset(&meye.grabq); + kfifo_reset(&meye.doneq); return 0; } @@ -933,7 +933,7 @@ static int meyeioc_qbuf_capt(int *nb) mchip_cont_compression_start(); meye.grab_buffer[*nb].state = MEYE_BUF_USING; - kfifo_put(meye.grabq, (unsigned char *)nb, sizeof(int)); + kfifo_put(&meye.grabq, (unsigned char *)nb, sizeof(int)); mutex_unlock(&meye.lock); return 0; @@ -965,7 +965,7 @@ static int meyeioc_sync(struct file *file, void *fh, int *i) /* fall through */ case MEYE_BUF_DONE: meye.grab_buffer[*i].state = MEYE_BUF_UNUSED; - kfifo_get(meye.doneq, (unsigned char *)&unused, sizeof(int)); + kfifo_get(&meye.doneq, (unsigned char *)&unused, sizeof(int)); } *i = meye.grab_buffer[*i].size; mutex_unlock(&meye.lock); @@ -1452,7 +1452,7 @@ static int vidioc_qbuf(struct file *file, void *fh, struct v4l2_buffer *buf) buf->flags |= V4L2_BUF_FLAG_QUEUED; buf->flags &= ~V4L2_BUF_FLAG_DONE; meye.grab_buffer[buf->index].state = MEYE_BUF_USING; - kfifo_put(meye.grabq, (unsigned char *)&buf->index, sizeof(int)); + kfifo_put(&meye.grabq, (unsigned char *)&buf->index, sizeof(int)); mutex_unlock(&meye.lock); return 0; @@ -1467,18 +1467,18 @@ static int vidioc_dqbuf(struct file *file, void *fh, struct v4l2_buffer *buf) mutex_lock(&meye.lock); - if (kfifo_len(meye.doneq) == 0 && file->f_flags & O_NONBLOCK) { + if (kfifo_len(&meye.doneq) == 0 && file->f_flags & O_NONBLOCK) { mutex_unlock(&meye.lock); return -EAGAIN; } if (wait_event_interruptible(meye.proc_list, - kfifo_len(meye.doneq) != 0) < 0) { + kfifo_len(&meye.doneq) != 0) < 0) { mutex_unlock(&meye.lock); return -EINTR; } - if (!kfifo_get(meye.doneq, (unsigned char *)&reqnr, + if (!kfifo_get(&meye.doneq, (unsigned char *)&reqnr, sizeof(int))) { mutex_unlock(&meye.lock); return -EBUSY; @@ -1529,8 +1529,8 @@ static int vidioc_streamoff(struct file *file, void *fh, enum v4l2_buf_type i) { mutex_lock(&meye.lock); mchip_hic_stop(); - kfifo_reset(meye.grabq); - kfifo_reset(meye.doneq); + kfifo_reset(&meye.grabq); + kfifo_reset(&meye.doneq); for (i = 0; i < MEYE_MAX_BUFNBRS; i++) meye.grab_buffer[i].state = MEYE_BUF_UNUSED; @@ -1572,7 +1572,7 @@ static unsigned int meye_poll(struct file *file, poll_table *wait) mutex_lock(&meye.lock); poll_wait(file, &meye.proc_list, wait); - if (kfifo_len(meye.doneq)) + if (kfifo_len(&meye.doneq)) res = POLLIN | POLLRDNORM; mutex_unlock(&meye.lock); return res; @@ -1745,16 +1745,14 @@ static int __devinit meye_probe(struct pci_dev *pcidev, } spin_lock_init(&meye.grabq_lock); - meye.grabq = kfifo_alloc(sizeof(int) * MEYE_MAX_BUFNBRS, GFP_KERNEL, - &meye.grabq_lock); - if (IS_ERR(meye.grabq)) { + if (kfifo_alloc(&meye.grabq, sizeof(int) * MEYE_MAX_BUFNBRS, GFP_KERNEL, + &meye.grabq_lock)) { printk(KERN_ERR "meye: fifo allocation failed\n"); goto outkfifoalloc1; } spin_lock_init(&meye.doneq_lock); - meye.doneq = kfifo_alloc(sizeof(int) * MEYE_MAX_BUFNBRS, GFP_KERNEL, - &meye.doneq_lock); - if (IS_ERR(meye.doneq)) { + if (kfifo_alloc(&meye.doneq, sizeof(int) * MEYE_MAX_BUFNBRS, GFP_KERNEL, + &meye.doneq_lock)) { printk(KERN_ERR "meye: fifo allocation failed\n"); goto outkfifoalloc2; } @@ -1868,9 +1866,9 @@ outregions: outenabledev: sony_pic_camera_command(SONY_PIC_COMMAND_SETCAMERA, 0); outsonypienable: - kfifo_free(meye.doneq); + kfifo_free(&meye.doneq); outkfifoalloc2: - kfifo_free(meye.grabq); + kfifo_free(&meye.grabq); outkfifoalloc1: vfree(meye.grab_temp); outvmalloc: @@ -1901,8 +1899,8 @@ static void __devexit meye_remove(struct pci_dev *pcidev) sony_pic_camera_command(SONY_PIC_COMMAND_SETCAMERA, 0); - kfifo_free(meye.doneq); - kfifo_free(meye.grabq); + kfifo_free(&meye.doneq); + kfifo_free(&meye.grabq); vfree(meye.grab_temp); |