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fs/adfs: dir: use pointers to access directory head/tails

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Add and use pointers in the adfs_dir structure to access the directory
head and tail structures, which will always be contiguous in a buffer.
This allows us to avoid memcpy()ing the data in the new directory code,
making it slightly more efficient.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Russell King
2019-12-09 11:10:21 +00:00
committed by Al Viro
parent 4287e4deb1
commit 016936b321
3 changed files with 29 additions and 36 deletions
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42
fs/adfs/dir_f.c
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@@ -58,7 +58,7 @@ static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
#define bufoff(_bh,_idx) \
({ int _buf = _idx >> blocksize_bits; \
int _off = _idx - (_buf << blocksize_bits);\
(u8 *)(_bh[_buf]->b_data + _off); \
(void *)(_bh[_buf]->b_data + _off); \
})
/*
@@ -139,18 +139,18 @@ static int adfs_dir_read(struct super_block *sb, u32 indaddr,
if (ret)
return ret;
memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));
dir->dirhead = bufoff(dir->bh, 0);
dir->newtail = bufoff(dir->bh, 2007);
if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq ||
memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
if (dir->dirhead->startmasseq != dir->newtail->endmasseq ||
memcmp(&dir->dirhead->startname, &dir->newtail->endname, 4))
goto bad_dir;
if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
memcmp(&dir->dirhead.startname, "Hugo", 4))
if (memcmp(&dir->dirhead->startname, "Nick", 4) &&
memcmp(&dir->dirhead->startname, "Hugo", 4))
goto bad_dir;
if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
if (adfs_dir_checkbyte(dir) != dir->newtail->dircheckbyte)
goto bad_dir;
return 0;
@@ -275,7 +275,7 @@ static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
if (ret)
adfs_error(sb, "unable to read directory");
else
dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3);
dir->parent_id = adfs_readval(dir->newtail->dirparent, 3);
return ret;
}
@@ -322,7 +322,6 @@ static int adfs_f_iterate(struct adfs_dir *dir, struct dir_context *ctx)
static int
adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
{
struct super_block *sb = dir->sb;
int ret;
ret = adfs_dir_find_entry(dir, obj->indaddr);
@@ -336,33 +335,26 @@ adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
/*
* Increment directory sequence number
*/
dir->bh[0]->b_data[0] += 1;
dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1;
dir->dirhead->startmasseq += 1;
dir->newtail->endmasseq += 1;
ret = adfs_dir_checkbyte(dir);
/*
* Update directory check byte
*/
dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret;
dir->newtail->dircheckbyte = ret;
#if 1
{
const unsigned int blocksize_bits = sb->s_blocksize_bits;
memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead));
memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail));
if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq ||
memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4))
if (dir->dirhead->startmasseq != dir->newtail->endmasseq ||
memcmp(&dir->dirhead->startname, &dir->newtail->endname, 4))
goto bad_dir;
if (memcmp(&dir->dirhead.startname, "Nick", 4) &&
memcmp(&dir->dirhead.startname, "Hugo", 4))
if (memcmp(&dir->dirhead->startname, "Nick", 4) &&
memcmp(&dir->dirhead->startname, "Hugo", 4))
goto bad_dir;
if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte)
if (adfs_dir_checkbyte(dir) != dir->newtail->dircheckbyte)
goto bad_dir;
}
#endif
ret = 0;
out: