1 files changed, 724 insertions, 0 deletions

diff --git a/drivers/staging/exfat/exfat_cache.c b/drivers/staging/exfat/exfat_cache.c
new file mode 100644
index 000000000000..1565ce65d39f
--- /dev/null
+++ b/drivers/staging/exfat/exfat_cache.c
@@ -0,0 +1,724 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/fs.h>
+#include <linux/mutex.h>
+#include "exfat.h"
+
+#define LOCKBIT		0x01
+#define DIRTYBIT	0x02
+
+/* Local variables */
+static DEFINE_SEMAPHORE(f_sem);
+static DEFINE_SEMAPHORE(b_sem);
+
+static struct buf_cache_t *FAT_cache_find(struct super_block *sb, sector_t sec)
+{
+	s32 off;
+	struct buf_cache_t *bp, *hp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	off = (sec +
+	       (sec >> p_fs->sectors_per_clu_bits)) & (FAT_CACHE_HASH_SIZE - 1);
+
+	hp = &p_fs->FAT_cache_hash_list[off];
+	for (bp = hp->hash_next; bp != hp; bp = bp->hash_next) {
+		if ((bp->drv == p_fs->drv) && (bp->sec == sec)) {
+			WARN(!bp->buf_bh,
+			     "[EXFAT] FAT_cache has no bh. It will make system panic.\n");
+
+			touch_buffer(bp->buf_bh);
+			return bp;
+		}
+	}
+	return NULL;
+}
+
+static void push_to_mru(struct buf_cache_t *bp, struct buf_cache_t *list)
+{
+	bp->next = list->next;
+	bp->prev = list;
+	list->next->prev = bp;
+	list->next = bp;
+}
+
+static void push_to_lru(struct buf_cache_t *bp, struct buf_cache_t *list)
+{
+	bp->prev = list->prev;
+	bp->next = list;
+	list->prev->next = bp;
+	list->prev = bp;
+}
+
+static void move_to_mru(struct buf_cache_t *bp, struct buf_cache_t *list)
+{
+	bp->prev->next = bp->next;
+	bp->next->prev = bp->prev;
+	push_to_mru(bp, list);
+}
+
+static void move_to_lru(struct buf_cache_t *bp, struct buf_cache_t *list)
+{
+	bp->prev->next = bp->next;
+	bp->next->prev = bp->prev;
+	push_to_lru(bp, list);
+}
+
+static struct buf_cache_t *FAT_cache_get(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	bp = p_fs->FAT_cache_lru_list.prev;
+
+	move_to_mru(bp, &p_fs->FAT_cache_lru_list);
+	return bp;
+}
+
+static void FAT_cache_insert_hash(struct super_block *sb,
+				  struct buf_cache_t *bp)
+{
+	s32 off;
+	struct buf_cache_t *hp;
+	struct fs_info_t *p_fs;
+
+	p_fs = &(EXFAT_SB(sb)->fs_info);
+	off = (bp->sec +
+	       (bp->sec >> p_fs->sectors_per_clu_bits)) &
+		(FAT_CACHE_HASH_SIZE - 1);
+
+	hp = &p_fs->FAT_cache_hash_list[off];
+	bp->hash_next = hp->hash_next;
+	bp->hash_prev = hp;
+	hp->hash_next->hash_prev = bp;
+	hp->hash_next = bp;
+}
+
+static void FAT_cache_remove_hash(struct buf_cache_t *bp)
+{
+	(bp->hash_prev)->hash_next = bp->hash_next;
+	(bp->hash_next)->hash_prev = bp->hash_prev;
+}
+
+static void buf_cache_insert_hash(struct super_block *sb,
+				  struct buf_cache_t *bp)
+{
+	s32 off;
+	struct buf_cache_t *hp;
+	struct fs_info_t *p_fs;
+
+	p_fs = &(EXFAT_SB(sb)->fs_info);
+	off = (bp->sec +
+	       (bp->sec >> p_fs->sectors_per_clu_bits)) &
+		(BUF_CACHE_HASH_SIZE - 1);
+
+	hp = &p_fs->buf_cache_hash_list[off];
+	bp->hash_next = hp->hash_next;
+	bp->hash_prev = hp;
+	hp->hash_next->hash_prev = bp;
+	hp->hash_next = bp;
+}
+
+static void buf_cache_remove_hash(struct buf_cache_t *bp)
+{
+	(bp->hash_prev)->hash_next = bp->hash_next;
+	(bp->hash_next)->hash_prev = bp->hash_prev;
+}
+
+void buf_init(struct super_block *sb)
+{
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	int i;
+
+	/* LRU list */
+	p_fs->FAT_cache_lru_list.next = &p_fs->FAT_cache_lru_list;
+	p_fs->FAT_cache_lru_list.prev = &p_fs->FAT_cache_lru_list;
+
+	for (i = 0; i < FAT_CACHE_SIZE; i++) {
+		p_fs->FAT_cache_array[i].drv = -1;
+		p_fs->FAT_cache_array[i].sec = ~0;
+		p_fs->FAT_cache_array[i].flag = 0;
+		p_fs->FAT_cache_array[i].buf_bh = NULL;
+		p_fs->FAT_cache_array[i].prev = NULL;
+		p_fs->FAT_cache_array[i].next = NULL;
+		push_to_mru(&p_fs->FAT_cache_array[i],
+			    &p_fs->FAT_cache_lru_list);
+	}
+
+	p_fs->buf_cache_lru_list.next = &p_fs->buf_cache_lru_list;
+	p_fs->buf_cache_lru_list.prev = &p_fs->buf_cache_lru_list;
+
+	for (i = 0; i < BUF_CACHE_SIZE; i++) {
+		p_fs->buf_cache_array[i].drv = -1;
+		p_fs->buf_cache_array[i].sec = ~0;
+		p_fs->buf_cache_array[i].flag = 0;
+		p_fs->buf_cache_array[i].buf_bh = NULL;
+		p_fs->buf_cache_array[i].prev = NULL;
+		p_fs->buf_cache_array[i].next = NULL;
+		push_to_mru(&p_fs->buf_cache_array[i],
+			    &p_fs->buf_cache_lru_list);
+	}
+
+	/* HASH list */
+	for (i = 0; i < FAT_CACHE_HASH_SIZE; i++) {
+		p_fs->FAT_cache_hash_list[i].drv = -1;
+		p_fs->FAT_cache_hash_list[i].sec = ~0;
+		p_fs->FAT_cache_hash_list[i].hash_next =
+			&p_fs->FAT_cache_hash_list[i];
+		p_fs->FAT_cache_hash_list[i].hash_prev =
+			&p_fs->FAT_cache_hash_list[i];
+	}
+
+	for (i = 0; i < FAT_CACHE_SIZE; i++)
+		FAT_cache_insert_hash(sb, &p_fs->FAT_cache_array[i]);
+
+	for (i = 0; i < BUF_CACHE_HASH_SIZE; i++) {
+		p_fs->buf_cache_hash_list[i].drv = -1;
+		p_fs->buf_cache_hash_list[i].sec = ~0;
+		p_fs->buf_cache_hash_list[i].hash_next =
+			&p_fs->buf_cache_hash_list[i];
+		p_fs->buf_cache_hash_list[i].hash_prev =
+			&p_fs->buf_cache_hash_list[i];
+	}
+
+	for (i = 0; i < BUF_CACHE_SIZE; i++)
+		buf_cache_insert_hash(sb, &p_fs->buf_cache_array[i]);
+}
+
+void buf_shutdown(struct super_block *sb)
+{
+}
+
+static int __FAT_read(struct super_block *sb, u32 loc, u32 *content)
+{
+	s32 off;
+	u32 _content;
+	sector_t sec;
+	u8 *fat_sector, *fat_entry;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
+
+	if (p_fs->vol_type == FAT12) {
+		sec = p_fs->FAT1_start_sector +
+			((loc + (loc >> 1)) >> p_bd->sector_size_bits);
+		off = (loc + (loc >> 1)) & p_bd->sector_size_mask;
+
+		if (off == (p_bd->sector_size - 1)) {
+			fat_sector = FAT_getblk(sb, sec);
+			if (!fat_sector)
+				return -1;
+
+			_content = (u32)fat_sector[off];
+
+			fat_sector = FAT_getblk(sb, ++sec);
+			if (!fat_sector)
+				return -1;
+
+			_content |= (u32)fat_sector[0] << 8;
+		} else {
+			fat_sector = FAT_getblk(sb, sec);
+			if (!fat_sector)
+				return -1;
+
+			fat_entry = &fat_sector[off];
+			_content = GET16(fat_entry);
+		}
+
+		if (loc & 1)
+			_content >>= 4;
+
+		_content &= 0x00000FFF;
+
+		if (_content >= CLUSTER_16(0x0FF8)) {
+			*content = CLUSTER_32(~0);
+			return 0;
+		}
+		*content = CLUSTER_32(_content);
+		return 0;
+	} else if (p_fs->vol_type == FAT16) {
+		sec = p_fs->FAT1_start_sector +
+			(loc >> (p_bd->sector_size_bits - 1));
+		off = (loc << 1) & p_bd->sector_size_mask;
+
+		fat_sector = FAT_getblk(sb, sec);
+		if (!fat_sector)
+			return -1;
+
+		fat_entry = &fat_sector[off];
+
+		_content = GET16_A(fat_entry);
+
+		_content &= 0x0000FFFF;
+
+		if (_content >= CLUSTER_16(0xFFF8)) {
+			*content = CLUSTER_32(~0);
+			return 0;
+		}
+		*content = CLUSTER_32(_content);
+		return 0;
+	} else if (p_fs->vol_type == FAT32) {
+		sec = p_fs->FAT1_start_sector +
+			(loc >> (p_bd->sector_size_bits - 2));
+		off = (loc << 2) & p_bd->sector_size_mask;
+
+		fat_sector = FAT_getblk(sb, sec);
+		if (!fat_sector)
+			return -1;
+
+		fat_entry = &fat_sector[off];
+
+		_content = GET32_A(fat_entry);
+
+		_content &= 0x0FFFFFFF;
+
+		if (_content >= CLUSTER_32(0x0FFFFFF8)) {
+			*content = CLUSTER_32(~0);
+			return 0;
+		}
+		*content = CLUSTER_32(_content);
+		return 0;
+	} else if (p_fs->vol_type == EXFAT) {
+		sec = p_fs->FAT1_start_sector +
+			(loc >> (p_bd->sector_size_bits - 2));
+		off = (loc << 2) & p_bd->sector_size_mask;
+
+		fat_sector = FAT_getblk(sb, sec);
+		if (!fat_sector)
+			return -1;
+
+		fat_entry = &fat_sector[off];
+		_content = GET32_A(fat_entry);
+
+		if (_content >= CLUSTER_32(0xFFFFFFF8)) {
+			*content = CLUSTER_32(~0);
+			return 0;
+		}
+		*content = CLUSTER_32(_content);
+		return 0;
+	}
+
+	/* Unknown volume type, throw in the towel and go home */
+	*content = CLUSTER_32(~0);
+	return 0;
+}
+
+/* in : sb, loc
+ * out: content
+ * returns 0 on success
+ *            -1 on error
+ */
+int FAT_read(struct super_block *sb, u32 loc, u32 *content)
+{
+	s32 ret;
+
+	down(&f_sem);
+	ret = __FAT_read(sb, loc, content);
+	up(&f_sem);
+
+	return ret;
+}
+
+static s32 __FAT_write(struct super_block *sb, u32 loc, u32 content)
+{
+	s32 off;
+	sector_t sec;
+	u8 *fat_sector, *fat_entry;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
+
+	if (p_fs->vol_type == FAT12) {
+		content &= 0x00000FFF;
+
+		sec = p_fs->FAT1_start_sector +
+			((loc + (loc >> 1)) >> p_bd->sector_size_bits);
+		off = (loc + (loc >> 1)) & p_bd->sector_size_mask;
+
+		fat_sector = FAT_getblk(sb, sec);
+		if (!fat_sector)
+			return -1;
+
+		if (loc & 1) { /* odd */
+			content <<= 4;
+
+			if (off == (p_bd->sector_size - 1)) {
+				fat_sector[off] = (u8)(content |
+						       (fat_sector[off] &
+							0x0F));
+				FAT_modify(sb, sec);
+
+				fat_sector = FAT_getblk(sb, ++sec);
+				if (!fat_sector)
+					return -1;
+
+				fat_sector[0] = (u8)(content >> 8);
+			} else {
+				fat_entry = &fat_sector[off];
+				content |= GET16(fat_entry) & 0x000F;
+
+				SET16(fat_entry, content);
+			}
+		} else { /* even */
+			fat_sector[off] = (u8)(content);
+
+			if (off == (p_bd->sector_size - 1)) {
+				fat_sector[off] = (u8)(content);
+				FAT_modify(sb, sec);
+
+				fat_sector = FAT_getblk(sb, ++sec);
+				if (!fat_sector)
+					return -1;
+				fat_sector[0] = (u8)((fat_sector[0] & 0xF0) |
+						     (content >> 8));
+			} else {
+				fat_entry = &fat_sector[off];
+				content |= GET16(fat_entry) & 0xF000;
+
+				SET16(fat_entry, content);
+			}
+		}
+	}
+
+	else if (p_fs->vol_type == FAT16) {
+		content &= 0x0000FFFF;
+
+		sec = p_fs->FAT1_start_sector + (loc >>
+						 (p_bd->sector_size_bits - 1));
+		off = (loc << 1) & p_bd->sector_size_mask;
+
+		fat_sector = FAT_getblk(sb, sec);
+		if (!fat_sector)
+			return -1;
+
+		fat_entry = &fat_sector[off];
+
+		SET16_A(fat_entry, content);
+	} else if (p_fs->vol_type == FAT32) {
+		content &= 0x0FFFFFFF;
+
+		sec = p_fs->FAT1_start_sector + (loc >>
+						 (p_bd->sector_size_bits - 2));
+		off = (loc << 2) & p_bd->sector_size_mask;
+
+		fat_sector = FAT_getblk(sb, sec);
+		if (!fat_sector)
+			return -1;
+
+		fat_entry = &fat_sector[off];
+
+		content |= GET32_A(fat_entry) & 0xF0000000;
+
+		SET32_A(fat_entry, content);
+	} else { /* p_fs->vol_type == EXFAT */
+		sec = p_fs->FAT1_start_sector + (loc >>
+						 (p_bd->sector_size_bits - 2));
+		off = (loc << 2) & p_bd->sector_size_mask;
+
+		fat_sector = FAT_getblk(sb, sec);
+		if (!fat_sector)
+			return -1;
+
+		fat_entry = &fat_sector[off];
+
+		SET32_A(fat_entry, content);
+	}
+
+	FAT_modify(sb, sec);
+	return 0;
+}
+
+int FAT_write(struct super_block *sb, u32 loc, u32 content)
+{
+	s32 ret;
+
+	down(&f_sem);
+	ret = __FAT_write(sb, loc, content);
+	up(&f_sem);
+
+	return ret;
+}
+
+u8 *FAT_getblk(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	bp = FAT_cache_find(sb, sec);
+	if (bp) {
+		move_to_mru(bp, &p_fs->FAT_cache_lru_list);
+		return bp->buf_bh->b_data;
+	}
+
+	bp = FAT_cache_get(sb, sec);
+
+	FAT_cache_remove_hash(bp);
+
+	bp->drv = p_fs->drv;
+	bp->sec = sec;
+	bp->flag = 0;
+
+	FAT_cache_insert_hash(sb, bp);
+
+	if (sector_read(sb, sec, &bp->buf_bh, 1) != FFS_SUCCESS) {
+		FAT_cache_remove_hash(bp);
+		bp->drv = -1;
+		bp->sec = ~0;
+		bp->flag = 0;
+		bp->buf_bh = NULL;
+
+		move_to_lru(bp, &p_fs->FAT_cache_lru_list);
+		return NULL;
+	}
+
+	return bp->buf_bh->b_data;
+}
+
+void FAT_modify(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+
+	bp = FAT_cache_find(sb, sec);
+	if (bp)
+		sector_write(sb, sec, bp->buf_bh, 0);
+}
+
+void FAT_release_all(struct super_block *sb)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	down(&f_sem);
+
+	bp = p_fs->FAT_cache_lru_list.next;
+	while (bp != &p_fs->FAT_cache_lru_list) {
+		if (bp->drv == p_fs->drv) {
+			bp->drv = -1;
+			bp->sec = ~0;
+			bp->flag = 0;
+
+			if (bp->buf_bh) {
+				__brelse(bp->buf_bh);
+				bp->buf_bh = NULL;
+			}
+		}
+		bp = bp->next;
+	}
+
+	up(&f_sem);
+}
+
+void FAT_sync(struct super_block *sb)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	down(&f_sem);
+
+	bp = p_fs->FAT_cache_lru_list.next;
+	while (bp != &p_fs->FAT_cache_lru_list) {
+		if ((bp->drv == p_fs->drv) && (bp->flag & DIRTYBIT)) {
+			sync_dirty_buffer(bp->buf_bh);
+			bp->flag &= ~(DIRTYBIT);
+		}
+		bp = bp->next;
+	}
+
+	up(&f_sem);
+}
+
+static struct buf_cache_t *buf_cache_find(struct super_block *sb, sector_t sec)
+{
+	s32 off;
+	struct buf_cache_t *bp, *hp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	off = (sec + (sec >> p_fs->sectors_per_clu_bits)) &
+		(BUF_CACHE_HASH_SIZE - 1);
+
+	hp = &p_fs->buf_cache_hash_list[off];
+	for (bp = hp->hash_next; bp != hp; bp = bp->hash_next) {
+		if ((bp->drv == p_fs->drv) && (bp->sec == sec)) {
+			touch_buffer(bp->buf_bh);
+			return bp;
+		}
+	}
+	return NULL;
+}
+
+static struct buf_cache_t *buf_cache_get(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	bp = p_fs->buf_cache_lru_list.prev;
+	while (bp->flag & LOCKBIT)
+		bp = bp->prev;
+
+	move_to_mru(bp, &p_fs->buf_cache_lru_list);
+	return bp;
+}
+
+static u8 *__buf_getblk(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	bp = buf_cache_find(sb, sec);
+	if (bp) {
+		move_to_mru(bp, &p_fs->buf_cache_lru_list);
+		return bp->buf_bh->b_data;
+	}
+
+	bp = buf_cache_get(sb, sec);
+
+	buf_cache_remove_hash(bp);
+
+	bp->drv = p_fs->drv;
+	bp->sec = sec;
+	bp->flag = 0;
+
+	buf_cache_insert_hash(sb, bp);
+
+	if (sector_read(sb, sec, &bp->buf_bh, 1) != FFS_SUCCESS) {
+		buf_cache_remove_hash(bp);
+		bp->drv = -1;
+		bp->sec = ~0;
+		bp->flag = 0;
+		bp->buf_bh = NULL;
+
+		move_to_lru(bp, &p_fs->buf_cache_lru_list);
+		return NULL;
+	}
+
+	return bp->buf_bh->b_data;
+}
+
+u8 *buf_getblk(struct super_block *sb, sector_t sec)
+{
+	u8 *buf;
+
+	down(&b_sem);
+	buf = __buf_getblk(sb, sec);
+	up(&b_sem);
+
+	return buf;
+}
+
+void buf_modify(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+
+	down(&b_sem);
+
+	bp = buf_cache_find(sb, sec);
+	if (likely(bp))
+		sector_write(sb, sec, bp->buf_bh, 0);
+
+	WARN(!bp, "[EXFAT] failed to find buffer_cache(sector:%llu).\n",
+	     (unsigned long long)sec);
+
+	up(&b_sem);
+}
+
+void buf_lock(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+
+	down(&b_sem);
+
+	bp = buf_cache_find(sb, sec);
+	if (likely(bp))
+		bp->flag |= LOCKBIT;
+
+	WARN(!bp, "[EXFAT] failed to find buffer_cache(sector:%llu).\n",
+	     (unsigned long long)sec);
+
+	up(&b_sem);
+}
+
+void buf_unlock(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+
+	down(&b_sem);
+
+	bp = buf_cache_find(sb, sec);
+	if (likely(bp))
+		bp->flag &= ~(LOCKBIT);
+
+	WARN(!bp, "[EXFAT] failed to find buffer_cache(sector:%llu).\n",
+	     (unsigned long long)sec);
+
+	up(&b_sem);
+}
+
+void buf_release(struct super_block *sb, sector_t sec)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	down(&b_sem);
+
+	bp = buf_cache_find(sb, sec);
+	if (likely(bp)) {
+		bp->drv = -1;
+		bp->sec = ~0;
+		bp->flag = 0;
+
+		if (bp->buf_bh) {
+			__brelse(bp->buf_bh);
+			bp->buf_bh = NULL;
+		}
+
+		move_to_lru(bp, &p_fs->buf_cache_lru_list);
+	}
+
+	up(&b_sem);
+}
+
+void buf_release_all(struct super_block *sb)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	down(&b_sem);
+
+	bp = p_fs->buf_cache_lru_list.next;
+	while (bp != &p_fs->buf_cache_lru_list) {
+		if (bp->drv == p_fs->drv) {
+			bp->drv = -1;
+			bp->sec = ~0;
+			bp->flag = 0;
+
+			if (bp->buf_bh) {
+				__brelse(bp->buf_bh);
+				bp->buf_bh = NULL;
+			}
+		}
+		bp = bp->next;
+	}
+
+	up(&b_sem);
+}
+
+void buf_sync(struct super_block *sb)
+{
+	struct buf_cache_t *bp;
+	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
+
+	down(&b_sem);
+
+	bp = p_fs->buf_cache_lru_list.next;
+	while (bp != &p_fs->buf_cache_lru_list) {
+		if ((bp->drv == p_fs->drv) && (bp->flag & DIRTYBIT)) {
+			sync_dirty_buffer(bp->buf_bh);
+			bp->flag &= ~(DIRTYBIT);
+		}
+		bp = bp->next;
+	}
+
+	up(&b_sem);
+}