android_kernel_samsung_msm8976/fs/f2fs/segment.h
Jaegeuk Kim ac5d156c78 f2fs: modify the number of issued pages to merge IOs
When testing f2fs on an SSD, I found some 128 page IOs followed by 1 page IO
were issued by f2fs_write_node_pages.
This means that there were some mishandling flows which degrades performance.

Previous f2fs_write_node_pages determines the number of pages to be written,
nr_to_write, as follows.

1. The bio_get_nr_vecs returns 129 pages.
2. The bio_alloc makes a room for 128 pages.
3. The initial 128 pages go into one bio.
4. The existing bio is submitted, and a new bio is prepared for the last 1 page.
5. Finally, sync_node_pages submits the last 1 page bio.

The problem is from the use of bio_get_nr_vecs, so this patch replace it
with max_hw_blocks using queue_max_sectors.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-04-30 12:07:32 +09:00

637 lines
19 KiB
C

/*
* fs/f2fs/segment.h
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/blkdev.h>
/* constant macro */
#define NULL_SEGNO ((unsigned int)(~0))
#define NULL_SECNO ((unsigned int)(~0))
/* L: Logical segment # in volume, R: Relative segment # in main area */
#define GET_L2R_SEGNO(free_i, segno) (segno - free_i->start_segno)
#define GET_R2L_SEGNO(free_i, segno) (segno + free_i->start_segno)
#define IS_DATASEG(t) \
((t == CURSEG_HOT_DATA) || (t == CURSEG_COLD_DATA) || \
(t == CURSEG_WARM_DATA))
#define IS_NODESEG(t) \
((t == CURSEG_HOT_NODE) || (t == CURSEG_COLD_NODE) || \
(t == CURSEG_WARM_NODE))
#define IS_CURSEG(sbi, seg) \
((seg == CURSEG_I(sbi, CURSEG_HOT_DATA)->segno) || \
(seg == CURSEG_I(sbi, CURSEG_WARM_DATA)->segno) || \
(seg == CURSEG_I(sbi, CURSEG_COLD_DATA)->segno) || \
(seg == CURSEG_I(sbi, CURSEG_HOT_NODE)->segno) || \
(seg == CURSEG_I(sbi, CURSEG_WARM_NODE)->segno) || \
(seg == CURSEG_I(sbi, CURSEG_COLD_NODE)->segno))
#define IS_CURSEC(sbi, secno) \
((secno == CURSEG_I(sbi, CURSEG_HOT_DATA)->segno / \
sbi->segs_per_sec) || \
(secno == CURSEG_I(sbi, CURSEG_WARM_DATA)->segno / \
sbi->segs_per_sec) || \
(secno == CURSEG_I(sbi, CURSEG_COLD_DATA)->segno / \
sbi->segs_per_sec) || \
(secno == CURSEG_I(sbi, CURSEG_HOT_NODE)->segno / \
sbi->segs_per_sec) || \
(secno == CURSEG_I(sbi, CURSEG_WARM_NODE)->segno / \
sbi->segs_per_sec) || \
(secno == CURSEG_I(sbi, CURSEG_COLD_NODE)->segno / \
sbi->segs_per_sec)) \
#define START_BLOCK(sbi, segno) \
(SM_I(sbi)->seg0_blkaddr + \
(GET_R2L_SEGNO(FREE_I(sbi), segno) << sbi->log_blocks_per_seg))
#define NEXT_FREE_BLKADDR(sbi, curseg) \
(START_BLOCK(sbi, curseg->segno) + curseg->next_blkoff)
#define MAIN_BASE_BLOCK(sbi) (SM_I(sbi)->main_blkaddr)
#define GET_SEGOFF_FROM_SEG0(sbi, blk_addr) \
((blk_addr) - SM_I(sbi)->seg0_blkaddr)
#define GET_SEGNO_FROM_SEG0(sbi, blk_addr) \
(GET_SEGOFF_FROM_SEG0(sbi, blk_addr) >> sbi->log_blocks_per_seg)
#define GET_SEGNO(sbi, blk_addr) \
(((blk_addr == NULL_ADDR) || (blk_addr == NEW_ADDR)) ? \
NULL_SEGNO : GET_L2R_SEGNO(FREE_I(sbi), \
GET_SEGNO_FROM_SEG0(sbi, blk_addr)))
#define GET_SECNO(sbi, segno) \
((segno) / sbi->segs_per_sec)
#define GET_ZONENO_FROM_SEGNO(sbi, segno) \
((segno / sbi->segs_per_sec) / sbi->secs_per_zone)
#define GET_SUM_BLOCK(sbi, segno) \
((sbi->sm_info->ssa_blkaddr) + segno)
#define GET_SUM_TYPE(footer) ((footer)->entry_type)
#define SET_SUM_TYPE(footer, type) ((footer)->entry_type = type)
#define SIT_ENTRY_OFFSET(sit_i, segno) \
(segno % sit_i->sents_per_block)
#define SIT_BLOCK_OFFSET(sit_i, segno) \
(segno / SIT_ENTRY_PER_BLOCK)
#define START_SEGNO(sit_i, segno) \
(SIT_BLOCK_OFFSET(sit_i, segno) * SIT_ENTRY_PER_BLOCK)
#define f2fs_bitmap_size(nr) \
(BITS_TO_LONGS(nr) * sizeof(unsigned long))
#define TOTAL_SEGS(sbi) (SM_I(sbi)->main_segments)
#define TOTAL_SECS(sbi) (sbi->total_sections)
#define SECTOR_FROM_BLOCK(sbi, blk_addr) \
(blk_addr << ((sbi)->log_blocksize - F2FS_LOG_SECTOR_SIZE))
#define SECTOR_TO_BLOCK(sbi, sectors) \
(sectors >> ((sbi)->log_blocksize - F2FS_LOG_SECTOR_SIZE))
/* during checkpoint, bio_private is used to synchronize the last bio */
struct bio_private {
struct f2fs_sb_info *sbi;
bool is_sync;
void *wait;
};
/*
* indicate a block allocation direction: RIGHT and LEFT.
* RIGHT means allocating new sections towards the end of volume.
* LEFT means the opposite direction.
*/
enum {
ALLOC_RIGHT = 0,
ALLOC_LEFT
};
/*
* In the victim_sel_policy->alloc_mode, there are two block allocation modes.
* LFS writes data sequentially with cleaning operations.
* SSR (Slack Space Recycle) reuses obsolete space without cleaning operations.
*/
enum {
LFS = 0,
SSR
};
/*
* In the victim_sel_policy->gc_mode, there are two gc, aka cleaning, modes.
* GC_CB is based on cost-benefit algorithm.
* GC_GREEDY is based on greedy algorithm.
*/
enum {
GC_CB = 0,
GC_GREEDY
};
/*
* BG_GC means the background cleaning job.
* FG_GC means the on-demand cleaning job.
*/
enum {
BG_GC = 0,
FG_GC
};
/* for a function parameter to select a victim segment */
struct victim_sel_policy {
int alloc_mode; /* LFS or SSR */
int gc_mode; /* GC_CB or GC_GREEDY */
unsigned long *dirty_segmap; /* dirty segment bitmap */
unsigned int offset; /* last scanned bitmap offset */
unsigned int ofs_unit; /* bitmap search unit */
unsigned int min_cost; /* minimum cost */
unsigned int min_segno; /* segment # having min. cost */
};
struct seg_entry {
unsigned short valid_blocks; /* # of valid blocks */
unsigned char *cur_valid_map; /* validity bitmap of blocks */
/*
* # of valid blocks and the validity bitmap stored in the the last
* checkpoint pack. This information is used by the SSR mode.
*/
unsigned short ckpt_valid_blocks;
unsigned char *ckpt_valid_map;
unsigned char type; /* segment type like CURSEG_XXX_TYPE */
unsigned long long mtime; /* modification time of the segment */
};
struct sec_entry {
unsigned int valid_blocks; /* # of valid blocks in a section */
};
struct segment_allocation {
void (*allocate_segment)(struct f2fs_sb_info *, int, bool);
};
struct sit_info {
const struct segment_allocation *s_ops;
block_t sit_base_addr; /* start block address of SIT area */
block_t sit_blocks; /* # of blocks used by SIT area */
block_t written_valid_blocks; /* # of valid blocks in main area */
char *sit_bitmap; /* SIT bitmap pointer */
unsigned int bitmap_size; /* SIT bitmap size */
unsigned long *dirty_sentries_bitmap; /* bitmap for dirty sentries */
unsigned int dirty_sentries; /* # of dirty sentries */
unsigned int sents_per_block; /* # of SIT entries per block */
struct mutex sentry_lock; /* to protect SIT cache */
struct seg_entry *sentries; /* SIT segment-level cache */
struct sec_entry *sec_entries; /* SIT section-level cache */
/* for cost-benefit algorithm in cleaning procedure */
unsigned long long elapsed_time; /* elapsed time after mount */
unsigned long long mounted_time; /* mount time */
unsigned long long min_mtime; /* min. modification time */
unsigned long long max_mtime; /* max. modification time */
};
struct free_segmap_info {
unsigned int start_segno; /* start segment number logically */
unsigned int free_segments; /* # of free segments */
unsigned int free_sections; /* # of free sections */
rwlock_t segmap_lock; /* free segmap lock */
unsigned long *free_segmap; /* free segment bitmap */
unsigned long *free_secmap; /* free section bitmap */
};
/* Notice: The order of dirty type is same with CURSEG_XXX in f2fs.h */
enum dirty_type {
DIRTY_HOT_DATA, /* dirty segments assigned as hot data logs */
DIRTY_WARM_DATA, /* dirty segments assigned as warm data logs */
DIRTY_COLD_DATA, /* dirty segments assigned as cold data logs */
DIRTY_HOT_NODE, /* dirty segments assigned as hot node logs */
DIRTY_WARM_NODE, /* dirty segments assigned as warm node logs */
DIRTY_COLD_NODE, /* dirty segments assigned as cold node logs */
DIRTY, /* to count # of dirty segments */
PRE, /* to count # of entirely obsolete segments */
NR_DIRTY_TYPE
};
struct dirty_seglist_info {
const struct victim_selection *v_ops; /* victim selction operation */
unsigned long *dirty_segmap[NR_DIRTY_TYPE];
struct mutex seglist_lock; /* lock for segment bitmaps */
int nr_dirty[NR_DIRTY_TYPE]; /* # of dirty segments */
unsigned long *victim_secmap; /* background GC victims */
};
/* victim selection function for cleaning and SSR */
struct victim_selection {
int (*get_victim)(struct f2fs_sb_info *, unsigned int *,
int, int, char);
};
/* for active log information */
struct curseg_info {
struct mutex curseg_mutex; /* lock for consistency */
struct f2fs_summary_block *sum_blk; /* cached summary block */
unsigned char alloc_type; /* current allocation type */
unsigned int segno; /* current segment number */
unsigned short next_blkoff; /* next block offset to write */
unsigned int zone; /* current zone number */
unsigned int next_segno; /* preallocated segment */
};
/*
* inline functions
*/
static inline struct curseg_info *CURSEG_I(struct f2fs_sb_info *sbi, int type)
{
return (struct curseg_info *)(SM_I(sbi)->curseg_array + type);
}
static inline struct seg_entry *get_seg_entry(struct f2fs_sb_info *sbi,
unsigned int segno)
{
struct sit_info *sit_i = SIT_I(sbi);
return &sit_i->sentries[segno];
}
static inline struct sec_entry *get_sec_entry(struct f2fs_sb_info *sbi,
unsigned int segno)
{
struct sit_info *sit_i = SIT_I(sbi);
return &sit_i->sec_entries[GET_SECNO(sbi, segno)];
}
static inline unsigned int get_valid_blocks(struct f2fs_sb_info *sbi,
unsigned int segno, int section)
{
/*
* In order to get # of valid blocks in a section instantly from many
* segments, f2fs manages two counting structures separately.
*/
if (section > 1)
return get_sec_entry(sbi, segno)->valid_blocks;
else
return get_seg_entry(sbi, segno)->valid_blocks;
}
static inline void seg_info_from_raw_sit(struct seg_entry *se,
struct f2fs_sit_entry *rs)
{
se->valid_blocks = GET_SIT_VBLOCKS(rs);
se->ckpt_valid_blocks = GET_SIT_VBLOCKS(rs);
memcpy(se->cur_valid_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
memcpy(se->ckpt_valid_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
se->type = GET_SIT_TYPE(rs);
se->mtime = le64_to_cpu(rs->mtime);
}
static inline void seg_info_to_raw_sit(struct seg_entry *se,
struct f2fs_sit_entry *rs)
{
unsigned short raw_vblocks = (se->type << SIT_VBLOCKS_SHIFT) |
se->valid_blocks;
rs->vblocks = cpu_to_le16(raw_vblocks);
memcpy(rs->valid_map, se->cur_valid_map, SIT_VBLOCK_MAP_SIZE);
memcpy(se->ckpt_valid_map, rs->valid_map, SIT_VBLOCK_MAP_SIZE);
se->ckpt_valid_blocks = se->valid_blocks;
rs->mtime = cpu_to_le64(se->mtime);
}
static inline unsigned int find_next_inuse(struct free_segmap_info *free_i,
unsigned int max, unsigned int segno)
{
unsigned int ret;
read_lock(&free_i->segmap_lock);
ret = find_next_bit(free_i->free_segmap, max, segno);
read_unlock(&free_i->segmap_lock);
return ret;
}
static inline void __set_free(struct f2fs_sb_info *sbi, unsigned int segno)
{
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int secno = segno / sbi->segs_per_sec;
unsigned int start_segno = secno * sbi->segs_per_sec;
unsigned int next;
write_lock(&free_i->segmap_lock);
clear_bit(segno, free_i->free_segmap);
free_i->free_segments++;
next = find_next_bit(free_i->free_segmap, TOTAL_SEGS(sbi), start_segno);
if (next >= start_segno + sbi->segs_per_sec) {
clear_bit(secno, free_i->free_secmap);
free_i->free_sections++;
}
write_unlock(&free_i->segmap_lock);
}
static inline void __set_inuse(struct f2fs_sb_info *sbi,
unsigned int segno)
{
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int secno = segno / sbi->segs_per_sec;
set_bit(segno, free_i->free_segmap);
free_i->free_segments--;
if (!test_and_set_bit(secno, free_i->free_secmap))
free_i->free_sections--;
}
static inline void __set_test_and_free(struct f2fs_sb_info *sbi,
unsigned int segno)
{
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int secno = segno / sbi->segs_per_sec;
unsigned int start_segno = secno * sbi->segs_per_sec;
unsigned int next;
write_lock(&free_i->segmap_lock);
if (test_and_clear_bit(segno, free_i->free_segmap)) {
free_i->free_segments++;
next = find_next_bit(free_i->free_segmap, TOTAL_SEGS(sbi),
start_segno);
if (next >= start_segno + sbi->segs_per_sec) {
if (test_and_clear_bit(secno, free_i->free_secmap))
free_i->free_sections++;
}
}
write_unlock(&free_i->segmap_lock);
}
static inline void __set_test_and_inuse(struct f2fs_sb_info *sbi,
unsigned int segno)
{
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int secno = segno / sbi->segs_per_sec;
write_lock(&free_i->segmap_lock);
if (!test_and_set_bit(segno, free_i->free_segmap)) {
free_i->free_segments--;
if (!test_and_set_bit(secno, free_i->free_secmap))
free_i->free_sections--;
}
write_unlock(&free_i->segmap_lock);
}
static inline void get_sit_bitmap(struct f2fs_sb_info *sbi,
void *dst_addr)
{
struct sit_info *sit_i = SIT_I(sbi);
memcpy(dst_addr, sit_i->sit_bitmap, sit_i->bitmap_size);
}
static inline block_t written_block_count(struct f2fs_sb_info *sbi)
{
struct sit_info *sit_i = SIT_I(sbi);
block_t vblocks;
mutex_lock(&sit_i->sentry_lock);
vblocks = sit_i->written_valid_blocks;
mutex_unlock(&sit_i->sentry_lock);
return vblocks;
}
static inline unsigned int free_segments(struct f2fs_sb_info *sbi)
{
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int free_segs;
read_lock(&free_i->segmap_lock);
free_segs = free_i->free_segments;
read_unlock(&free_i->segmap_lock);
return free_segs;
}
static inline int reserved_segments(struct f2fs_sb_info *sbi)
{
return SM_I(sbi)->reserved_segments;
}
static inline unsigned int free_sections(struct f2fs_sb_info *sbi)
{
struct free_segmap_info *free_i = FREE_I(sbi);
unsigned int free_secs;
read_lock(&free_i->segmap_lock);
free_secs = free_i->free_sections;
read_unlock(&free_i->segmap_lock);
return free_secs;
}
static inline unsigned int prefree_segments(struct f2fs_sb_info *sbi)
{
return DIRTY_I(sbi)->nr_dirty[PRE];
}
static inline unsigned int dirty_segments(struct f2fs_sb_info *sbi)
{
return DIRTY_I(sbi)->nr_dirty[DIRTY_HOT_DATA] +
DIRTY_I(sbi)->nr_dirty[DIRTY_WARM_DATA] +
DIRTY_I(sbi)->nr_dirty[DIRTY_COLD_DATA] +
DIRTY_I(sbi)->nr_dirty[DIRTY_HOT_NODE] +
DIRTY_I(sbi)->nr_dirty[DIRTY_WARM_NODE] +
DIRTY_I(sbi)->nr_dirty[DIRTY_COLD_NODE];
}
static inline int overprovision_segments(struct f2fs_sb_info *sbi)
{
return SM_I(sbi)->ovp_segments;
}
static inline int overprovision_sections(struct f2fs_sb_info *sbi)
{
return ((unsigned int) overprovision_segments(sbi)) / sbi->segs_per_sec;
}
static inline int reserved_sections(struct f2fs_sb_info *sbi)
{
return ((unsigned int) reserved_segments(sbi)) / sbi->segs_per_sec;
}
static inline bool need_SSR(struct f2fs_sb_info *sbi)
{
return (free_sections(sbi) < overprovision_sections(sbi));
}
static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, int freed)
{
int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
if (sbi->por_doing)
return false;
return ((free_sections(sbi) + freed) <= (node_secs + 2 * dent_secs +
reserved_sections(sbi)));
}
static inline int utilization(struct f2fs_sb_info *sbi)
{
return div_u64(valid_user_blocks(sbi) * 100, sbi->user_block_count);
}
/*
* Sometimes f2fs may be better to drop out-of-place update policy.
* So, if fs utilization is over MIN_IPU_UTIL, then f2fs tries to write
* data in the original place likewise other traditional file systems.
* But, currently set 100 in percentage, which means it is disabled.
* See below need_inplace_update().
*/
#define MIN_IPU_UTIL 100
static inline bool need_inplace_update(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
if (S_ISDIR(inode->i_mode))
return false;
if (need_SSR(sbi) && utilization(sbi) > MIN_IPU_UTIL)
return true;
return false;
}
static inline unsigned int curseg_segno(struct f2fs_sb_info *sbi,
int type)
{
struct curseg_info *curseg = CURSEG_I(sbi, type);
return curseg->segno;
}
static inline unsigned char curseg_alloc_type(struct f2fs_sb_info *sbi,
int type)
{
struct curseg_info *curseg = CURSEG_I(sbi, type);
return curseg->alloc_type;
}
static inline unsigned short curseg_blkoff(struct f2fs_sb_info *sbi, int type)
{
struct curseg_info *curseg = CURSEG_I(sbi, type);
return curseg->next_blkoff;
}
static inline void check_seg_range(struct f2fs_sb_info *sbi, unsigned int segno)
{
unsigned int end_segno = SM_I(sbi)->segment_count - 1;
BUG_ON(segno > end_segno);
}
/*
* This function is used for only debugging.
* NOTE: In future, we have to remove this function.
*/
static inline void verify_block_addr(struct f2fs_sb_info *sbi, block_t blk_addr)
{
struct f2fs_sm_info *sm_info = SM_I(sbi);
block_t total_blks = sm_info->segment_count << sbi->log_blocks_per_seg;
block_t start_addr = sm_info->seg0_blkaddr;
block_t end_addr = start_addr + total_blks - 1;
BUG_ON(blk_addr < start_addr);
BUG_ON(blk_addr > end_addr);
}
/*
* Summary block is always treated as invalid block
*/
static inline void check_block_count(struct f2fs_sb_info *sbi,
int segno, struct f2fs_sit_entry *raw_sit)
{
struct f2fs_sm_info *sm_info = SM_I(sbi);
unsigned int end_segno = sm_info->segment_count - 1;
int valid_blocks = 0;
int i;
/* check segment usage */
BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg);
/* check boundary of a given segment number */
BUG_ON(segno > end_segno);
/* check bitmap with valid block count */
for (i = 0; i < sbi->blocks_per_seg; i++)
if (f2fs_test_bit(i, raw_sit->valid_map))
valid_blocks++;
BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);
}
static inline pgoff_t current_sit_addr(struct f2fs_sb_info *sbi,
unsigned int start)
{
struct sit_info *sit_i = SIT_I(sbi);
unsigned int offset = SIT_BLOCK_OFFSET(sit_i, start);
block_t blk_addr = sit_i->sit_base_addr + offset;
check_seg_range(sbi, start);
/* calculate sit block address */
if (f2fs_test_bit(offset, sit_i->sit_bitmap))
blk_addr += sit_i->sit_blocks;
return blk_addr;
}
static inline pgoff_t next_sit_addr(struct f2fs_sb_info *sbi,
pgoff_t block_addr)
{
struct sit_info *sit_i = SIT_I(sbi);
block_addr -= sit_i->sit_base_addr;
if (block_addr < sit_i->sit_blocks)
block_addr += sit_i->sit_blocks;
else
block_addr -= sit_i->sit_blocks;
return block_addr + sit_i->sit_base_addr;
}
static inline void set_to_next_sit(struct sit_info *sit_i, unsigned int start)
{
unsigned int block_off = SIT_BLOCK_OFFSET(sit_i, start);
if (f2fs_test_bit(block_off, sit_i->sit_bitmap))
f2fs_clear_bit(block_off, sit_i->sit_bitmap);
else
f2fs_set_bit(block_off, sit_i->sit_bitmap);
}
static inline unsigned long long get_mtime(struct f2fs_sb_info *sbi)
{
struct sit_info *sit_i = SIT_I(sbi);
return sit_i->elapsed_time + CURRENT_TIME_SEC.tv_sec -
sit_i->mounted_time;
}
static inline void set_summary(struct f2fs_summary *sum, nid_t nid,
unsigned int ofs_in_node, unsigned char version)
{
sum->nid = cpu_to_le32(nid);
sum->ofs_in_node = cpu_to_le16(ofs_in_node);
sum->version = version;
}
static inline block_t start_sum_block(struct f2fs_sb_info *sbi)
{
return __start_cp_addr(sbi) +
le32_to_cpu(F2FS_CKPT(sbi)->cp_pack_start_sum);
}
static inline block_t sum_blk_addr(struct f2fs_sb_info *sbi, int base, int type)
{
return __start_cp_addr(sbi) +
le32_to_cpu(F2FS_CKPT(sbi)->cp_pack_total_block_count)
- (base + 1) + type;
}
static inline bool sec_usage_check(struct f2fs_sb_info *sbi, unsigned int secno)
{
if (IS_CURSEC(sbi, secno) || (sbi->cur_victim_sec == secno))
return true;
return false;
}
static inline unsigned int max_hw_blocks(struct f2fs_sb_info *sbi)
{
struct block_device *bdev = sbi->sb->s_bdev;
struct request_queue *q = bdev_get_queue(bdev);
return SECTOR_TO_BLOCK(sbi, queue_max_sectors(q));
}