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Added lfsr_data_fetchmdir

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Like lfsr_data_fetchbtree/branch, lfsr_data_fetchmdir merges both the
data read/decode and fetch steps into a single function that should
hopefully result in better code deduplication.

Unlike lfsr_data_fetchbtree/branch, this is actually a net positive for
code savings. And because we can abuse the mptr in the yet-uninit mdir,
we can even shave off a bit of stack:

                     code          stack
  default before:   36456           2680
  default after:    36436 (-0.1%)   2672 (-0.3%)

  ckfetches before: 36686           2712
  ckfetches after:  36674 (-0.0%)   2704 (-0.3%)
This commit is contained in:
Christopher Haster
2024-08-14 15:18:38 -05:00
parent 3b1b571d5c
commit 770578d221
1 changed files with 28 additions and 35 deletions
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lfs.c
+28 -35
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@@ -7206,6 +7206,19 @@ static int lfsr_mdir_fetch(lfs_t *lfs, lfsr_mdir_t *mdir,
return LFS_ERR_CORRUPT;
}
static int lfsr_data_fetchmdir(lfs_t *lfs,
lfsr_data_t *data, lfsr_smid_t mid,
lfsr_mdir_t *mdir) {
// decode mptr and fetch
int err = lfsr_data_readmptr(lfs, data,
(lfsr_mptr_t*)mdir->rbyd.blocks);
if (err) {
return err;
}
return lfsr_mdir_fetch(lfs, mdir, mid, lfsr_mdir_mptr(mdir));
}
static int lfsr_mdir_lookupnext(lfs_t *lfs, const lfsr_mdir_t *mdir,
lfsr_tag_t tag,
lfsr_tag_t *tag_, lfsr_data_t *data_) {
@@ -7386,15 +7399,9 @@ static int lfsr_mtree_lookup(lfs_t *lfs, lfsr_smid_t mid,
LFS_ASSERT((lfsr_sbid_t)bid == lfsr_mid_bid(lfs, mid));
LFS_ASSERT(tag == LFSR_TAG_MDIR);
// decode mdir
lfsr_mptr_t mptr;
err = lfsr_data_readmptr(lfs, &data, &mptr);
if (err) {
return err;
}
// fetch mdir
return lfsr_mdir_fetch(lfs, mdir_, mid, &mptr);
return lfsr_data_fetchmdir(lfs, &data, mid,
mdir_);
}
}
@@ -8931,15 +8938,9 @@ static int lfsr_mtree_namelookup(lfs_t *lfs,
LFS_ASSERT(tag == LFSR_TAG_MDIR);
LFS_ASSERT(weight == (1U << lfs->mdir_bits));
// decode mdir
lfsr_mptr_t mptr;
int err = lfsr_data_readmptr(lfs, &data, &mptr);
if (err) {
return err;
}
// fetch mdir
err = lfsr_mdir_fetch(lfs, &mdir, bid-(weight-1), &mptr);
int err = lfsr_data_fetchmdir(lfs, &data, bid-(weight-1),
&mdir);
if (err) {
return err;
}
@@ -9194,8 +9195,9 @@ static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_traversal_t *t,
// found a new mroot
if (tag == LFSR_TAG_MROOT) {
lfsr_mptr_t mptr;
err = lfsr_data_readmptr(lfs, &data, &mptr);
// fetch this mroot
err = lfsr_data_fetchmdir(lfs, &data, -1,
&t->o.o.mdir);
if (err) {
return err;
}
@@ -9206,26 +9208,22 @@ static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_traversal_t *t,
// btree inner nodes require checksums of their pointers,
// so creating a valid cycle is actually quite difficult
//
if (lfsr_mptr_cmp(&mptr, &t->u.mtortoise.mptr) == 0) {
if (lfsr_mptr_cmp(
lfsr_mdir_mptr(&t->o.o.mdir),
&t->u.mtortoise.mptr) == 0) {
LFS_ERROR("Cycle detected during mtree traversal "
"0x{%"PRIx32",%"PRIx32"}",
mptr.blocks[0],
mptr.blocks[1]);
t->o.o.mdir.rbyd.blocks[0],
t->o.o.mdir.rbyd.blocks[1]);
return LFS_ERR_CORRUPT;
}
if (t->u.mtortoise.step == (1U << t->u.mtortoise.power)) {
t->u.mtortoise.mptr = mptr;
t->u.mtortoise.mptr = *lfsr_mdir_mptr(&t->o.o.mdir);
t->u.mtortoise.step = 0;
t->u.mtortoise.power += 1;
}
t->u.mtortoise.step += 1;
// fetch this mroot
err = lfsr_mdir_fetch(lfs, &t->o.o.mdir, -1, &mptr);
if (err) {
return err;
}
if (tag_) {
*tag_ = LFSR_TAG_MDIR;
}
@@ -9237,13 +9235,8 @@ static int lfsr_mtree_traverse_(lfs_t *lfs, lfsr_traversal_t *t,
// found an mdir?
} else if (tag == LFSR_TAG_MDIR) {
// fetch this mdir
lfsr_mptr_t mptr;
err = lfsr_data_readmptr(lfs, &data, &mptr);
if (err) {
return err;
}
err = lfsr_mdir_fetch(lfs, &t->o.o.mdir, 0, &mptr);
err = lfsr_data_fetchmdir(lfs, &data, 0,
&t->o.o.mdir);
if (err) {
return err;
}