Messages in this thread | | | Date | Tue, 5 Sep 2006 11:22:08 +0200 (MEST) | From | Jan Engelhardt <> | Subject | Re: [PATCH 07/16] GFS2: Directory handling |
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>> > >+static inline int __gfs2_dirent_find(const struct gfs2_dirent *dent, >> > >+ const struct qstr *name, int ret) >> > >+{ >> > >+ if (dent->de_inum.no_addr != 0 && >> > >+ be32_to_cpu(dent->de_hash) == name->hash && >> > >+ be16_to_cpu(dent->de_name_len) == name->len && >> > >+ memcmp((char *)(dent+1), name->name, name->len) == 0) >> > >> > Nocast. >> > >> ok > >actually, sizeof(*dent) != 1, so how can a non-casted memcmp be correct >here?
There is an implicit reinterpret_cast<> from char* to void* when using memcmp, because void* is what memcpy takes as first argument. So, in effect we are doing
memcmp((void *)(char *)(dent + 1), ...)
and that cast is, in this case, redundant, meaning we can do
memcmp((void *)(dent + 1), ...)
But since conversion from and to void* is implicit in C, we can do
memcmp(dent + 1, ...)
>> > >+ if ((char *)cur + cur_rec_len >= bh_end) { >> > >+ if ((char *)cur + cur_rec_len > bh_end) { >> > >+ gfs2_consist_inode(dip); >> > >+ return -EIO; >> > >+ } >> > >+ return -ENOENT; >> > >+ } >> > >> > if((char *)cur + cur_rec_len > bh_end) { >> > gfs2_consist_inode(dip); >> > return -EIO; >> > } else if((char *)cur + cur_rec_len == bh_end) >> > return -ENOENT; >> > >> ok > >this one is not OK! Firstly, Jan, and i mentioned this before, please >stop using 'if(', it is highly inconsistent and against basic taste. We >only use this construct for function calls (and macros), not for C >statements.
Now there is no rule in CodingStyle for this yet. Plus, I was wanting to show how to reorder the construct, so change in whitespace between "if" and "(" is outoftopic.
11:17 gwdg-wb04A:~/linux > grep -Pri '(if|for|while)\(' . | wc -l 24242
[To be honest, I also present the other number:] 11:17 gwdg-wb04A:~/linux > grep -Pri '(if|for|while) \(' . | wc -l 380895
Although a minority, it does not seem so uncommon.
>Secondly, whenever we have curly braces in the first block, we tend to >do it in the second block too, for easier parsing. I.e.: > > if ((char *)cur + cur_rec_len > bh_end) { > gfs2_consist_inode(dip); > return -EIO; > } else { > if ((char *)cur + cur_rec_len == bh_end) > return -ENOENT; > }
I would very much like to do just this
many insns; } else if(...) { single insn; }
but again, some people think no {} should be there because it's just a single insn. Though I don't go harvesting in lkml.org archives right now to prove this claim.
>Thirdly, the original code was quite fine as-is! What's the point of >introducing random perturbations like this? It is an open invitation for >the introduction of bugs... So unless there is a clear style reason to >do a change, i'd suggest to not touch the code.
Intent was reduction of indent. ""The answer to that is that if you need more than 3 levels of indentation, you're screwed anyway, and should fix your program."" so says CodingStyle, though the 3-level barrier was only touched this time.
No offense!
Jan Engelhardt -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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