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V4L/DVB: drivers/media/IR - improve keytable code

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The attached patch rewrites much of the keytable code in
drivers/media/IR/ir-keytable.c.

The scancodes are now inserted into the array in sorted
order which allows for a binary search on lookup.

The code has also been shrunk by about 150 lines.

In addition it fixes the following bugs:

Any use of ir_seek_table() was racy.

ir_dev->driver_name is leaked between ir_input_register() and
ir_input_unregister().

ir_setkeycode() unconditionally does clear_bit() on dev->keybit
when removing a mapping, but there might be another mapping with
a different scancode and the same keycode.

This version has been updated to incorporate patch feedback from
Mauro Carvalho Chehab.

[mchehab@redhat.com: Fix a conflict with RC keytable breakup patches and input changes]

Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
David Härdeman 2010-04-02 15:58:28 -03:00 committed by Mauro Carvalho Chehab
parent bdf1c98e42
commit b3074c0a3f
2 changed files with 216 additions and 356 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

568
drivers/media/IR/ir-keytable.c
View File

@ -17,344 +17,214 @@
#include <linux/slab.h>
#include <media/ir-common.h>
#define IR_TAB_MIN_SIZE 32
#define IR_TAB_MAX_SIZE 1024
/* Sizes are in bytes, 256 bytes allows for 32 entries on x64 */
#define IR_TAB_MIN_SIZE 256
#define IR_TAB_MAX_SIZE 8192
/**
* ir_seek_table() - returns the element order on the table
* @rc_tab: the ir_scancode_table with the keymap to be used
* @scancode: the scancode that we're seeking
* ir_resize_table() - resizes a scancode table if necessary
* @rc_tab: the ir_scancode_table to resize
* @return: zero on success or a negative error code
*
* This routine is used by the input routines when a key is pressed at the
* IR. The scancode is received and needs to be converted into a keycode.
* If the key is not found, it returns KEY_UNKNOWN. Otherwise, returns the
* corresponding keycode from the table.
* This routine will shrink the ir_scancode_table if it has lots of
* unused entries and grow it if it is full.
*/
static int ir_seek_table(struct ir_scancode_table *rc_tab, u32 scancode)
static int ir_resize_table(struct ir_scancode_table *rc_tab)
{
unsigned int oldalloc = rc_tab->alloc;
unsigned int newalloc = oldalloc;
struct ir_scancode *oldscan = rc_tab->scan;
struct ir_scancode *newscan;
if (rc_tab->size == rc_tab->len) {
/* All entries in use -> grow keytable */
if (rc_tab->alloc >= IR_TAB_MAX_SIZE)
return -ENOMEM;
newalloc *= 2;
IR_dprintk(1, "Growing table to %u bytes\n", newalloc);
}
if ((rc_tab->len * 3 < rc_tab->size) && (oldalloc > IR_TAB_MIN_SIZE)) {
/* Less than 1/3 of entries in use -> shrink keytable */
newalloc /= 2;
IR_dprintk(1, "Shrinking table to %u bytes\n", newalloc);
}
if (newalloc == oldalloc)
return 0;
newscan = kmalloc(newalloc, GFP_ATOMIC);
if (!newscan) {
IR_dprintk(1, "Failed to kmalloc %u bytes\n", newalloc);
return -ENOMEM;
}
memcpy(newscan, rc_tab->scan, rc_tab->len * sizeof(struct ir_scancode));
rc_tab->scan = newscan;
rc_tab->alloc = newalloc;
rc_tab->size = rc_tab->alloc / sizeof(struct ir_scancode);
kfree(oldscan);
return 0;
}
/**
* ir_do_setkeycode() - internal function to set a keycode in the
* scancode->keycode table
* @dev: the struct input_dev device descriptor
* @rc_tab: the struct ir_scancode_table to set the keycode in
* @scancode: the scancode for the ir command
* @keycode: the keycode for the ir command
* @return: -EINVAL if the keycode could not be inserted, otherwise zero.
*
* This routine is used internally to manipulate the scancode->keycode table.
* The caller has to hold @rc_tab->lock.
*/
static int ir_do_setkeycode(struct input_dev *dev,
struct ir_scancode_table *rc_tab,
unsigned scancode, unsigned keycode)
{
unsigned int i;
int old_keycode = KEY_RESERVED;
/* First check if we already have a mapping for this ir command */
for (i = 0; i < rc_tab->len; i++) {
/* Keytable is sorted from lowest to highest scancode */
if (rc_tab->scan[i].scancode > scancode)
break;
else if (rc_tab->scan[i].scancode < scancode)
continue;
old_keycode = rc_tab->scan[i].keycode;
rc_tab->scan[i].keycode = keycode;
/* Did the user wish to remove the mapping? */
if (keycode == KEY_RESERVED || keycode == KEY_UNKNOWN) {
rc_tab->len--;
memmove(&rc_tab->scan[i], &rc_tab->scan[i + 1],
(rc_tab->len - i) * sizeof(struct ir_scancode));
}
/* Possibly shrink the keytable, failure is not a problem */
ir_resize_table(rc_tab);
break;
}
if (old_keycode == KEY_RESERVED) {
/* No previous mapping found, we might need to grow the table */
if (ir_resize_table(rc_tab))
return -ENOMEM;
/* i is the proper index to insert our new keycode */
memmove(&rc_tab->scan[i + 1], &rc_tab->scan[i],
(rc_tab->len - i) * sizeof(struct ir_scancode));
rc_tab->scan[i].scancode = scancode;
rc_tab->scan[i].keycode = keycode;
rc_tab->len++;
set_bit(keycode, dev->keybit);
} else {
/* A previous mapping was updated... */
clear_bit(old_keycode, dev->keybit);
/* ...but another scancode might use the same keycode */
for (i = 0; i < rc_tab->len; i++) {
if (rc_tab->scan[i].keycode == old_keycode) {
set_bit(old_keycode, dev->keybit);
break;
}
}
}
return 0;
}
/**
* ir_setkeycode() - set a keycode in the scancode->keycode table
* @dev: the struct input_dev device descriptor
* @scancode: the desired scancode
* @keycode: result
* @return: -EINVAL if the keycode could not be inserted, otherwise zero.
*
* This routine is used to handle evdev EVIOCSKEY ioctl.
*/
static int ir_setkeycode(struct input_dev *dev,
unsigned int scancode, unsigned int keycode)
{
int rc;
unsigned long flags;
struct ir_scancode *keymap = rc_tab->scan;
struct ir_input_dev *ir_dev = input_get_drvdata(dev);
struct ir_scancode_table *rc_tab = &ir_dev->rc_tab;
spin_lock_irqsave(&rc_tab->lock, flags);
/* FIXME: replace it by a binary search */
for (rc = 0; rc < rc_tab->size; rc++)
if (keymap[rc].scancode == scancode)
goto exit;
/* Not found */
rc = -EINVAL;
exit:
rc = ir_do_setkeycode(dev, rc_tab, scancode, keycode);
spin_unlock_irqrestore(&rc_tab->lock, flags);
return rc;
}
/**
* ir_roundup_tablesize() - gets an optimum value for the table size
* @n_elems: minimum number of entries to store keycodes
* ir_setkeytable() - sets several entries in the scancode->keycode table
* @dev: the struct input_dev device descriptor
* @to: the struct ir_scancode_table to copy entries to
* @from: the struct ir_scancode_table to copy entries from
* @return: -EINVAL if all keycodes could not be inserted, otherwise zero.
*
* This routine is used to choose the keycode table size.
*
* In order to have some empty space for new keycodes,
* and knowing in advance that kmalloc allocates only power of two
* segments, it optimizes the allocated space to have some spare space
* for those new keycodes by using the maximum number of entries that
* will be effectively be allocated by kmalloc.
* In order to reduce the quantity of table resizes, it has a minimum
* table size of IR_TAB_MIN_SIZE.
* This routine is used to handle table initialization.
*/
static int ir_roundup_tablesize(int n_elems)
static int ir_setkeytable(struct input_dev *dev,
struct ir_scancode_table *to,
const struct ir_scancode_table *from)
{
size_t size;
struct ir_input_dev *ir_dev = input_get_drvdata(dev);
struct ir_scancode_table *rc_tab = &ir_dev->rc_tab;
unsigned long flags;
unsigned int i;
int rc = 0;
if (n_elems < IR_TAB_MIN_SIZE)
n_elems = IR_TAB_MIN_SIZE;
/*
* As kmalloc only allocates sizes of power of two, get as
* much entries as possible for the allocated memory segment
*/
size = roundup_pow_of_two(n_elems * sizeof(struct ir_scancode));
n_elems = size / sizeof(struct ir_scancode);
return n_elems;
}
/**
* ir_copy_table() - copies a keytable, discarding the unused entries
* @destin: destin table
* @origin: origin table
*
* Copies all entries where the keycode is not KEY_UNKNOWN/KEY_RESERVED
* Also copies table size and table protocol.
* NOTE: It shouldn't copy the lock field
*/
static int ir_copy_table(struct ir_scancode_table *destin,
const struct ir_scancode_table *origin)
{
int i, j = 0;
for (i = 0; i < origin->size; i++) {
if (origin->scan[i].keycode == KEY_UNKNOWN ||
origin->scan[i].keycode == KEY_RESERVED)
continue;
memcpy(&destin->scan[j], &origin->scan[i], sizeof(struct ir_scancode));
j++;
spin_lock_irqsave(&rc_tab->lock, flags);
for (i = 0; i < from->size; i++) {
rc = ir_do_setkeycode(dev, to, from->scan[i].scancode,
from->scan[i].keycode);
if (rc)
break;
}
destin->size = j;
destin->ir_type = origin->ir_type;
IR_dprintk(1, "Copied %d scancodes to the new keycode table\n", destin->size);
return 0;
spin_unlock_irqrestore(&rc_tab->lock, flags);
return rc;
}
/**
* ir_getkeycode() - get a keycode at the evdev scancode ->keycode table
* ir_getkeycode() - get a keycode from the scancode->keycode table
* @dev: the struct input_dev device descriptor
* @scancode: the desired scancode
* @keycode: the keycode to be retorned.
* @keycode: used to return the keycode, if found, or KEY_RESERVED
* @return: always returns zero.
*
* This routine is used to handle evdev EVIOCGKEY ioctl.
* If the key is not found, returns -EINVAL, otherwise, returns 0.
*/
static int ir_getkeycode(struct input_dev *dev,
unsigned int scancode, unsigned int *keycode)
{
int elem;
int start, end, mid;
unsigned long flags;
int key = KEY_RESERVED;
struct ir_input_dev *ir_dev = input_get_drvdata(dev);
struct ir_scancode_table *rc_tab = &ir_dev->rc_tab;
elem = ir_seek_table(rc_tab, scancode);
if (elem >= 0) {
*keycode = rc_tab->scan[elem].keycode;
return 0;
}
/*
* Scancode not found and table can't be expanded
*/
if (elem < 0 && rc_tab->size == IR_TAB_MAX_SIZE)
return -EINVAL;
/*
* If is there extra space, returns KEY_RESERVED,
* otherwise, input core won't let ir_setkeycode to work
*/
*keycode = KEY_RESERVED;
return 0;
}
/**
* ir_is_resize_needed() - Check if the table needs rezise
* @table: keycode table that may need to resize
* @n_elems: minimum number of entries to store keycodes
*
* Considering that kmalloc uses power of two storage areas, this
* routine detects if the real alloced size will change. If not, it
* just returns without doing nothing. Otherwise, it will extend or
* reduce the table size to meet the new needs.
*
* It returns 0 if no resize is needed, 1 otherwise.
*/
static int ir_is_resize_needed(struct ir_scancode_table *table, int n_elems)
{
int cur_size = ir_roundup_tablesize(table->size);
int new_size = ir_roundup_tablesize(n_elems);
if (cur_size == new_size)
return 0;
/* Resize is needed */
return 1;
}
/**
* ir_delete_key() - remove a keycode from the table
* @rc_tab: keycode table
* @elem: element to be removed
*
*/
static void ir_delete_key(struct ir_scancode_table *rc_tab, int elem)
{
unsigned long flags = 0;
int newsize = rc_tab->size - 1;
int resize = ir_is_resize_needed(rc_tab, newsize);
struct ir_scancode *oldkeymap = rc_tab->scan;
struct ir_scancode *newkeymap = NULL;
if (resize)
newkeymap = kzalloc(ir_roundup_tablesize(newsize) *
sizeof(*newkeymap), GFP_ATOMIC);
/* There's no memory for resize. Keep the old table */
if (!resize || !newkeymap) {
newkeymap = oldkeymap;
/* We'll modify the live table. Lock it */
spin_lock_irqsave(&rc_tab->lock, flags);
}
/*
* Copy the elements before the one that will be deleted
* if (!resize), both oldkeymap and newkeymap points
* to the same place, so, there's no need to copy
*/
if (resize && elem > 0)
memcpy(newkeymap, oldkeymap,
elem * sizeof(*newkeymap));
/*
* Copy the other elements overwriting the element to be removed
* This operation applies to both resize and non-resize case
*/
if (elem < newsize)
memcpy(&newkeymap[elem], &oldkeymap[elem + 1],
(newsize - elem) * sizeof(*newkeymap));
if (resize) {
/*
* As the copy happened to a temporary table, only here
* it needs to lock while replacing the table pointers
* to use the new table
*/
spin_lock_irqsave(&rc_tab->lock, flags);
rc_tab->size = newsize;
rc_tab->scan = newkeymap;
spin_unlock_irqrestore(&rc_tab->lock, flags);
/* Frees the old keytable */
kfree(oldkeymap);
} else {
rc_tab->size = newsize;
spin_unlock_irqrestore(&rc_tab->lock, flags);
}
}
/**
* ir_insert_key() - insert a keycode at the table
* @rc_tab: keycode table
* @scancode: the desired scancode
* @keycode: the keycode to be retorned.
*
*/
static int ir_insert_key(struct ir_scancode_table *rc_tab,
int scancode, int keycode)
{
unsigned long flags;
int elem = rc_tab->size;
int newsize = rc_tab->size + 1;
int resize = ir_is_resize_needed(rc_tab, newsize);
struct ir_scancode *oldkeymap = rc_tab->scan;
struct ir_scancode *newkeymap;
if (resize) {
newkeymap = kzalloc(ir_roundup_tablesize(newsize) *
sizeof(*newkeymap), GFP_ATOMIC);
if (!newkeymap)
return -ENOMEM;
memcpy(newkeymap, oldkeymap,
rc_tab->size * sizeof(*newkeymap));
} else
newkeymap = oldkeymap;
/* Stores the new code at the table */
IR_dprintk(1, "#%d: New scan 0x%04x with key 0x%04x\n",
rc_tab->size, scancode, keycode);
spin_lock_irqsave(&rc_tab->lock, flags);
rc_tab->size = newsize;
if (resize) {
rc_tab->scan = newkeymap;
kfree(oldkeymap);
start = 0;
end = rc_tab->len - 1;
while (start <= end) {
mid = (start + end) / 2;
if (rc_tab->scan[mid].scancode < scancode)
start = mid + 1;
else if (rc_tab->scan[mid].scancode > scancode)
end = mid - 1;
else {
key = rc_tab->scan[mid].keycode;
break;
}
}
newkeymap[elem].scancode = scancode;
newkeymap[elem].keycode = keycode;
spin_unlock_irqrestore(&rc_tab->lock, flags);
return 0;
}
/**
* ir_setkeycode() - set a keycode at the evdev scancode ->keycode table
* @dev: the struct input_dev device descriptor
* @scancode: the desired scancode
* @keycode: the keycode to be retorned.
*
* This routine is used to handle evdev EVIOCSKEY ioctl.
* There's one caveat here: how can we increase the size of the table?
* If the key is not found, returns -EINVAL, otherwise, returns 0.
*/
static int ir_setkeycode(struct input_dev *dev,
unsigned int scancode, unsigned int keycode)
{
int rc = 0;
struct ir_input_dev *ir_dev = input_get_drvdata(dev);
struct ir_scancode_table *rc_tab = &ir_dev->rc_tab;
struct ir_scancode *keymap = rc_tab->scan;
unsigned long flags;
/*
* Handle keycode table deletions
*
* If userspace is adding a KEY_UNKNOWN or KEY_RESERVED,
* deal as a trial to remove an existing scancode attribution
* if table become too big, reduce it to save space
*/
if (keycode == KEY_UNKNOWN || keycode == KEY_RESERVED) {
rc = ir_seek_table(rc_tab, scancode);
if (rc < 0)
return 0;
IR_dprintk(1, "#%d: Deleting scan 0x%04x\n", rc, scancode);
clear_bit(keymap[rc].keycode, dev->keybit);
ir_delete_key(rc_tab, rc);
return 0;
}
/*
* Handle keycode replacements
*
* If the scancode exists, just replace by the new value
*/
rc = ir_seek_table(rc_tab, scancode);
if (rc >= 0) {
IR_dprintk(1, "#%d: Replacing scan 0x%04x with key 0x%04x\n",
rc, scancode, keycode);
clear_bit(keymap[rc].keycode, dev->keybit);
spin_lock_irqsave(&rc_tab->lock, flags);
keymap[rc].keycode = keycode;
spin_unlock_irqrestore(&rc_tab->lock, flags);
set_bit(keycode, dev->keybit);
return 0;
}
/*
* Handle new scancode inserts
*
* reallocate table if needed and insert a new keycode
*/
/* Avoid growing the table indefinitely */
if (rc_tab->size + 1 > IR_TAB_MAX_SIZE)
return -EINVAL;
rc = ir_insert_key(rc_tab, scancode, keycode);
if (rc < 0)
return rc;
set_bit(keycode, dev->keybit);
*keycode = key;
return 0;
}
@ -370,24 +240,12 @@ static int ir_setkeycode(struct input_dev *dev,
*/
u32 ir_g_keycode_from_table(struct input_dev *dev, u32 scancode)
{
struct ir_input_dev *ir_dev = input_get_drvdata(dev);
struct ir_scancode_table *rc_tab = &ir_dev->rc_tab;
struct ir_scancode *keymap = rc_tab->scan;
int elem;
int keycode;
elem = ir_seek_table(rc_tab, scancode);
if (elem >= 0) {
IR_dprintk(1, "%s: scancode 0x%04x keycode 0x%02x\n",
dev->name, scancode, keymap[elem].keycode);
return rc_tab->scan[elem].keycode;
}
printk(KERN_INFO "%s: unknown key for scancode 0x%04x\n",
dev->name, scancode);
/* Reports userspace that an unknown keycode were got */
return KEY_RESERVED;
ir_getkeycode(dev, scancode, &keycode);
IR_dprintk(1, "%s: scancode 0x%04x keycode 0x%02x\n",
dev->name, scancode, keycode);
return keycode;
}
EXPORT_SYMBOL_GPL(ir_g_keycode_from_table);
@ -477,8 +335,7 @@ int __ir_input_register(struct input_dev *input_dev,
const char *driver_name)
{
struct ir_input_dev *ir_dev;
struct ir_scancode *keymap = rc_tab->scan;
int i, rc;
int rc;
if (rc_tab->scan == NULL || !rc_tab->size)
return -EINVAL;
@ -487,55 +344,55 @@ int __ir_input_register(struct input_dev *input_dev,
if (!ir_dev)
return -ENOMEM;
spin_lock_init(&ir_dev->rc_tab.lock);
ir_dev->driver_name = kmalloc(strlen(driver_name) + 1, GFP_KERNEL);
if (!ir_dev->driver_name)
return -ENOMEM;
strcpy(ir_dev->driver_name, driver_name);
ir_dev->rc_tab.name = rc_tab->name;
ir_dev->rc_tab.size = ir_roundup_tablesize(rc_tab->size);
ir_dev->rc_tab.scan = kzalloc(ir_dev->rc_tab.size *
sizeof(struct ir_scancode), GFP_KERNEL);
if (!ir_dev->rc_tab.scan) {
kfree(ir_dev);
return -ENOMEM;
ir_dev->driver_name = kasprintf(GFP_KERNEL, "%s", driver_name);
if (!ir_dev->driver_name) {
rc = -ENOMEM;
goto out_dev;
}
IR_dprintk(1, "Allocated space for %d keycode entries (%zd bytes)\n",
ir_dev->rc_tab.size,
ir_dev->rc_tab.size * sizeof(ir_dev->rc_tab.scan));
input_dev->getkeycode = ir_getkeycode;
input_dev->setkeycode = ir_setkeycode;
input_set_drvdata(input_dev, ir_dev);
spin_lock_init(&ir_dev->rc_tab.lock);
ir_dev->rc_tab.name = rc_tab->name;
ir_dev->rc_tab.ir_type = rc_tab->ir_type;
ir_dev->rc_tab.alloc = roundup_pow_of_two(rc_tab->size *
sizeof(struct ir_scancode));
ir_dev->rc_tab.scan = kmalloc(ir_dev->rc_tab.alloc, GFP_KERNEL);
ir_dev->rc_tab.size = ir_dev->rc_tab.alloc / sizeof(struct ir_scancode);
if (!ir_dev->rc_tab.scan) {
rc = -ENOMEM;
goto out_name;
}
IR_dprintk(1, "Allocated space for %u keycode entries (%u bytes)\n",
ir_dev->rc_tab.size, ir_dev->rc_tab.alloc);
set_bit(EV_KEY, input_dev->evbit);
if (ir_setkeytable(input_dev, &ir_dev->rc_tab, rc_tab)) {
rc = -ENOMEM;
goto out_table;
}
ir_copy_table(&ir_dev->rc_tab, rc_tab);
ir_dev->props = props;
if (props && props->open)
input_dev->open = ir_open;
if (props && props->close)
input_dev->close = ir_close;
/* set the bits for the keys */
IR_dprintk(1, "key map size: %d\n", rc_tab->size);
for (i = 0; i < rc_tab->size; i++) {
IR_dprintk(1, "#%d: setting bit for keycode 0x%04x\n",
i, keymap[i].keycode);
set_bit(keymap[i].keycode, input_dev->keybit);
}
clear_bit(0, input_dev->keybit);
set_bit(EV_KEY, input_dev->evbit);
input_dev->getkeycode = ir_getkeycode;
input_dev->setkeycode = ir_setkeycode;
input_set_drvdata(input_dev, ir_dev);
rc = ir_register_class(input_dev);
if (rc < 0)
goto err;
goto out_table;
return 0;
err:
kfree(rc_tab->scan);
out_table:
kfree(ir_dev->rc_tab.scan);
out_name:
kfree(ir_dev->driver_name);
out_dev:
kfree(ir_dev);
return rc;
}
@ -564,6 +421,7 @@ void ir_input_unregister(struct input_dev *dev)
ir_unregister_class(dev);
kfree(ir_dev->driver_name);
kfree(ir_dev);
}
EXPORT_SYMBOL_GPL(ir_input_unregister);

4
include/media/ir-core.h
View File

@ -47,7 +47,9 @@ struct ir_scancode {
struct ir_scancode_table {
struct ir_scancode *scan;
int size;
unsigned int size; /* Max number of entries */
unsigned int len; /* Used number of entries */
unsigned int alloc; /* Size of *scan in bytes */
u64 ir_type;
char *name;
spinlock_t lock;