Messages in this thread | | | Date | Mon, 24 Nov 2008 16:19:31 +0200 | From | Adrian Hunter <> | Subject | Re: [PATCH] UBIFS: endian handling fixes and annotations |
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Sebastian Andrzej Siewior wrote: > * Artem Bityutskiy | 2008-11-21 19:19:24 [+0200]: > >> index 9ee6508..3f1f16b 100644 >> --- a/fs/ubifs/key.h >> +++ b/fs/ubifs/key.h >> @@ -345,7 +345,7 @@ static inline int key_type_flash(const struct ubifs_info *c, const void *k) >> { >> const union ubifs_key *key = k; >> >> - return le32_to_cpu(key->u32[1]) >> UBIFS_S_KEY_BLOCK_BITS; >> + return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS; > > If you would change such references to something like > |return le32_to_cpup(&key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS; > then on powerpc > > text data bss dec hex filename > 155384 1284 24 156692 26414 ubifs-b4.ko > 155372 1284 24 156680 26408 ubifs-after.ko > > because now it is possible to load the value as LE from memory instead > of loading it BE and swapping it afterwads.
Wouldn't that be true for every le32_to_cpu of an lvalue? Shame you can't do:
is_lvalue(x) ? le32_to_cpup(&(x)) : le32_to_cpu(x)
>> } >> >> /** >> @@ -416,7 +416,7 @@ static inline unsigned int key_block_flash(const struct ubifs_info *c, >> { >> const union ubifs_key *key = k; >> >> - return le32_to_cpu(key->u32[1]) & UBIFS_S_KEY_BLOCK_MASK; >> + return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK; >> } > > This and the previous change look like a bugfix for something that > should trigger during recovery or something? Shouldn't I fail in > ubifs_validate_entry() during recovery?
This is just about casting. key->u32[1] and key->j32[1] are the same object. There is no "real" bug in these two cases - just compilation warnings.
>> /** >> diff --git a/fs/ubifs/recovery.c b/fs/ubifs/recovery.c >> index 77d26c1..bed9742 100644 >> --- a/fs/ubifs/recovery.c >> +++ b/fs/ubifs/recovery.c >> @@ -168,12 +168,12 @@ static int write_rcvrd_mst_node(struct ubifs_info *c, >> struct ubifs_mst_node *mst) >> { >> int err = 0, lnum = UBIFS_MST_LNUM, sz = c->mst_node_alsz; >> - uint32_t save_flags; >> + __le32 save_flags; >> >> dbg_rcvry("recovery"); >> >> save_flags = mst->flags; >> - mst->flags = cpu_to_le32(le32_to_cpu(mst->flags) | UBIFS_MST_RCVRY); >> + mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY); > > another micro optimisation would be to use __constant_cpu_to_le32()
As per Harvey's reply.
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