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mtd: mtdblock: Dynamically allocate cache info structures
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Since we allocate struct mtd_blktrans_dev for each block device, we
can add our own structure members to the end.  Therefore embed
struct mtd_blktrans_dev in struct mtdblk_dev and remove the static
array of struct mtdblk_dev.  Also remove the redundant pointer to
struct mtd_info.

This is preparation for removing the static limit on the number of MTD
devices.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Ben Hutchings authored and David Woodhouse committed Feb 25, 2010
1 parent 24c1549 commit cbfe93e
Showing 1 changed file with 31 additions and 43 deletions.
74 changes: 31 additions & 43 deletions drivers/mtd/mtdblock.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,15 +19,15 @@
#include <linux/mutex.h>


static struct mtdblk_dev {
struct mtd_info *mtd;
struct mtdblk_dev {
struct mtd_blktrans_dev mbd;
int count;
struct mutex cache_mutex;
unsigned char *cache_data;
unsigned long cache_offset;
unsigned int cache_size;
enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
} *mtdblks[MAX_MTD_DEVICES];
};

static struct mutex mtdblks_lock;

Expand Down Expand Up @@ -98,7 +98,7 @@ static int erase_write (struct mtd_info *mtd, unsigned long pos,

static int write_cached_data (struct mtdblk_dev *mtdblk)
{
struct mtd_info *mtd = mtdblk->mtd;
struct mtd_info *mtd = mtdblk->mbd.mtd;
int ret;

if (mtdblk->cache_state != STATE_DIRTY)
Expand Down Expand Up @@ -128,7 +128,7 @@ static int write_cached_data (struct mtdblk_dev *mtdblk)
static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
int len, const char *buf)
{
struct mtd_info *mtd = mtdblk->mtd;
struct mtd_info *mtd = mtdblk->mbd.mtd;
unsigned int sect_size = mtdblk->cache_size;
size_t retlen;
int ret;
Expand Down Expand Up @@ -198,7 +198,7 @@ static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
int len, char *buf)
{
struct mtd_info *mtd = mtdblk->mtd;
struct mtd_info *mtd = mtdblk->mbd.mtd;
unsigned int sect_size = mtdblk->cache_size;
size_t retlen;
int ret;
Expand Down Expand Up @@ -244,16 +244,16 @@ static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos,
static int mtdblock_readsect(struct mtd_blktrans_dev *dev,
unsigned long block, char *buf)
{
struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
return do_cached_read(mtdblk, block<<9, 512, buf);
}

static int mtdblock_writesect(struct mtd_blktrans_dev *dev,
unsigned long block, char *buf)
{
struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) {
mtdblk->cache_data = vmalloc(mtdblk->mtd->erasesize);
mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize);
if (!mtdblk->cache_data)
return -EINTR;
/* -EINTR is not really correct, but it is the best match
Expand All @@ -266,37 +266,26 @@ static int mtdblock_writesect(struct mtd_blktrans_dev *dev,

static int mtdblock_open(struct mtd_blktrans_dev *mbd)
{
struct mtdblk_dev *mtdblk;
struct mtd_info *mtd = mbd->mtd;
int dev = mbd->devnum;
struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);

DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");

mutex_lock(&mtdblks_lock);
if (mtdblks[dev]) {
mtdblks[dev]->count++;
if (mtdblk->count) {
mtdblk->count++;
mutex_unlock(&mtdblks_lock);
return 0;
}

/* OK, it's not open. Create cache info for it */
mtdblk = kzalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
if (!mtdblk) {
mutex_unlock(&mtdblks_lock);
return -ENOMEM;
}

mtdblk->count = 1;
mtdblk->mtd = mtd;

mutex_init(&mtdblk->cache_mutex);
mtdblk->cache_state = STATE_EMPTY;
if ( !(mtdblk->mtd->flags & MTD_NO_ERASE) && mtdblk->mtd->erasesize) {
mtdblk->cache_size = mtdblk->mtd->erasesize;
if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
mtdblk->cache_size = mbd->mtd->erasesize;
mtdblk->cache_data = NULL;
}

mtdblks[dev] = mtdblk;
mutex_unlock(&mtdblks_lock);

DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
Expand All @@ -306,8 +295,7 @@ static int mtdblock_open(struct mtd_blktrans_dev *mbd)

static int mtdblock_release(struct mtd_blktrans_dev *mbd)
{
int dev = mbd->devnum;
struct mtdblk_dev *mtdblk = mtdblks[dev];
struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd);

DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");

Expand All @@ -318,12 +306,10 @@ static int mtdblock_release(struct mtd_blktrans_dev *mbd)
mutex_unlock(&mtdblk->cache_mutex);

if (!--mtdblk->count) {
/* It was the last usage. Free the device */
mtdblks[dev] = NULL;
if (mtdblk->mtd->sync)
mtdblk->mtd->sync(mtdblk->mtd);
/* It was the last usage. Free the cache */
if (mbd->mtd->sync)
mbd->mtd->sync(mbd->mtd);
vfree(mtdblk->cache_data);
kfree(mtdblk);
}

mutex_unlock(&mtdblks_lock);
Expand All @@ -335,40 +321,42 @@ static int mtdblock_release(struct mtd_blktrans_dev *mbd)

static int mtdblock_flush(struct mtd_blktrans_dev *dev)
{
struct mtdblk_dev *mtdblk = mtdblks[dev->devnum];
struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);

mutex_lock(&mtdblk->cache_mutex);
write_cached_data(mtdblk);
mutex_unlock(&mtdblk->cache_mutex);

if (mtdblk->mtd->sync)
mtdblk->mtd->sync(mtdblk->mtd);
if (dev->mtd->sync)
dev->mtd->sync(dev->mtd);
return 0;
}

static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
{
struct mtd_blktrans_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);
struct mtdblk_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL);

if (!dev)
return;

dev->mtd = mtd;
dev->devnum = mtd->index;
dev->mbd.mtd = mtd;
dev->mbd.devnum = mtd->index;

dev->size = mtd->size >> 9;
dev->tr = tr;
dev->mbd.size = mtd->size >> 9;
dev->mbd.tr = tr;

if (!(mtd->flags & MTD_WRITEABLE))
dev->readonly = 1;
dev->mbd.readonly = 1;

add_mtd_blktrans_dev(dev);
add_mtd_blktrans_dev(&dev->mbd);
}

static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
{
struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);

del_mtd_blktrans_dev(dev);
kfree(dev);
kfree(mtdblk);
}

static struct mtd_blktrans_ops mtdblock_tr = {
Expand Down

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