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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/nozomi.c
parent2ec91eec47f713e3d158ba5b28a24a85a2cf3650 (diff)
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/nozomi.c')
-rw-r--r--drivers/char/nozomi.c21
1 files changed, 10 insertions, 11 deletions
diff --git a/drivers/char/nozomi.c b/drivers/char/nozomi.c
index d3400b20444..0f39bec28b4 100644
--- a/drivers/char/nozomi.c
+++ b/drivers/char/nozomi.c
@@ -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;
@@ -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));
}
@@ -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) {
@@ -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...");
@@ -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);
@@ -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)) {
@@ -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);
@@ -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;