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/media/video/meye.c b/drivers/media/video/meye.c
index 6ffa64c..dacbbb8 100644
--- a/drivers/media/video/meye.c
+++ b/drivers/media/video/meye.c
@@ -800,7 +800,7 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
/* 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 @@
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 @@
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 @@
{
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 @@
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 @@
}
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 @@
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 @@
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);
