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kfifo: move struct kfifo in place
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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.

[[email protected]: fix warning]
Signed-off-by: Stefani Seibold <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: Andi Kleen <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@sstefani @torvalds
sstefani authored and torvalds committed Dec 22, 2009
1 parent 2ec91ee commit 4546548
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Showing 24 changed files with 238 additions and 259 deletions.
21 changes: 10 additions & 11 deletions drivers/char/nozomi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -358,7 +358,7 @@ struct port {
u8 update_flow_control;
struct ctrl_ul ctrl_ul;
struct ctrl_dl ctrl_dl;
struct kfifo *fifo_ul;
struct kfifo fifo_ul;
void __iomem *dl_addr[2];
u32 dl_size[2];
u8 toggle_dl;
Expand Down Expand Up @@ -685,8 +685,8 @@ static int nozomi_read_config_table(struct nozomi *dc)
dump_table(dc);

for (i = PORT_MDM; i < MAX_PORT; i++) {
dc->port[i].fifo_ul =
kfifo_alloc(FIFO_BUFFER_SIZE_UL, GFP_ATOMIC, NULL);
kfifo_alloc(&dc->port[i].fifo_ul,
FIFO_BUFFER_SIZE_UL, GFP_ATOMIC, NULL);
memset(&dc->port[i].ctrl_dl, 0, sizeof(struct ctrl_dl));
memset(&dc->port[i].ctrl_ul, 0, sizeof(struct ctrl_ul));
}
Expand Down Expand Up @@ -798,7 +798,7 @@ static int send_data(enum port_type index, struct nozomi *dc)
struct tty_struct *tty = tty_port_tty_get(&port->port);

/* Get data from tty and place in buf for now */
size = __kfifo_get(port->fifo_ul, dc->send_buf,
size = __kfifo_get(&port->fifo_ul, dc->send_buf,
ul_size < SEND_BUF_MAX ? ul_size : SEND_BUF_MAX);

if (size == 0) {
Expand Down Expand Up @@ -988,11 +988,11 @@ static int receive_flow_control(struct nozomi *dc)

} else if (old_ctrl.CTS == 0 && ctrl_dl.CTS == 1) {

if (__kfifo_len(dc->port[port].fifo_ul)) {
if (__kfifo_len(&dc->port[port].fifo_ul)) {
DBG1("Enable interrupt (0x%04X) on port: %d",
enable_ier, port);
DBG1("Data in buffer [%d], enable transmit! ",
__kfifo_len(dc->port[port].fifo_ul));
__kfifo_len(&dc->port[port].fifo_ul));
enable_transmit_ul(port, dc);
} else {
DBG1("No data in buffer...");
Expand Down Expand Up @@ -1536,8 +1536,7 @@ static void __devexit nozomi_card_exit(struct pci_dev *pdev)
free_irq(pdev->irq, dc);

for (i = 0; i < MAX_PORT; i++)
if (dc->port[i].fifo_ul)
kfifo_free(dc->port[i].fifo_ul);
kfifo_free(&dc->port[i].fifo_ul);

kfree(dc->send_buf);

Expand Down Expand Up @@ -1673,7 +1672,7 @@ static int ntty_write(struct tty_struct *tty, const unsigned char *buffer,
goto exit;
}

rval = __kfifo_put(port->fifo_ul, (unsigned char *)buffer, count);
rval = __kfifo_put(&port->fifo_ul, (unsigned char *)buffer, count);

/* notify card */
if (unlikely(dc == NULL)) {
Expand Down Expand Up @@ -1721,7 +1720,7 @@ static int ntty_write_room(struct tty_struct *tty)
if (!port->port.count)
goto exit;

room = port->fifo_ul->size - __kfifo_len(port->fifo_ul);
room = port->fifo_ul.size - __kfifo_len(&port->fifo_ul);

exit:
mutex_unlock(&port->tty_sem);
Expand Down Expand Up @@ -1878,7 +1877,7 @@ static s32 ntty_chars_in_buffer(struct tty_struct *tty)
goto exit_in_buffer;
}

rval = __kfifo_len(port->fifo_ul);
rval = __kfifo_len(&port->fifo_ul);

exit_in_buffer:
return rval;
Expand Down
40 changes: 19 additions & 21 deletions drivers/char/sonypi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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;

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -880,7 +880,7 @@ static irqreturn_t sonypi_irq(int irq, void *dev_id)
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);

Expand All @@ -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();
Expand All @@ -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++;
Expand All @@ -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;
}
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;
}

Expand All @@ -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;
}
Expand All @@ -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);
Expand All @@ -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;
}
Expand Down
9 changes: 5 additions & 4 deletions drivers/infiniband/hw/cxgb3/cxio_hal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@

#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/kfifo.h>

#include "t3_cpl.h"
#include "t3cdev.h"
Expand Down Expand Up @@ -75,13 +76,13 @@ struct cxio_hal_ctrl_qp {
};

struct cxio_hal_resource {
struct kfifo *tpt_fifo;
struct kfifo tpt_fifo;
spinlock_t tpt_fifo_lock;
struct kfifo *qpid_fifo;
struct kfifo qpid_fifo;
spinlock_t qpid_fifo_lock;
struct kfifo *cqid_fifo;
struct kfifo cqid_fifo;
spinlock_t cqid_fifo_lock;
struct kfifo *pdid_fifo;
struct kfifo pdid_fifo;
spinlock_t pdid_fifo_lock;
};

Expand Down
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