Messages in this thread Patch in this message | | | Date | Thu, 29 May 2008 21:54:50 +0100 (BST) | From | Hugh Dickins <> | Subject | [PATCH] generic_file_aio_read cleanups |
| |
As akpm points out, there's really no need for generic_file_aio_read to make a special case of count 0: just loop through nr_segs doing nothing. And as Harvey Harrison points out, there's no need to reset retval to 0 where it's already 0.
Signed-off-by: Hugh Dickins <hugh@veritas.com> --- Setting count (or ocount) to 0 before calling generic_segment_checks is unnecessary too; but reluctantly I'll leave that removal to someone with a wider range of gcc versions to hand - 4.1.2 and 4.2.1 don't warn about it, but perhaps others do - I forget which are the warniest versions.
mm/filemap.c | 44 ++++++++++++++++++++------------------------ 1 file changed, 20 insertions(+), 24 deletions(-)
--- 2.6.26-rc4/mm/filemap.c 2008-05-19 11:19:03.000000000 +0100 +++ linux/mm/filemap.c 2008-05-29 21:31:55.000000000 +0100 @@ -1199,7 +1199,6 @@ generic_file_aio_read(struct kiocb *iocb mapping = filp->f_mapping; inode = mapping->host; - retval = 0; if (!count) goto out; /* skip atime */ size = i_size_read(inode); @@ -1208,33 +1207,30 @@ generic_file_aio_read(struct kiocb *iocb iov, pos, nr_segs); if (retval > 0) *ppos = pos + retval; - } - if (likely(retval != 0)) { - file_accessed(filp); - goto out; + if (retval) { + file_accessed(filp); + goto out; + } } } - retval = 0; - if (count) { - for (seg = 0; seg < nr_segs; seg++) { - read_descriptor_t desc; - - desc.written = 0; - desc.arg.buf = iov[seg].iov_base; - desc.count = iov[seg].iov_len; - if (desc.count == 0) - continue; - desc.error = 0; - do_generic_file_read(filp,ppos,&desc,file_read_actor); - retval += desc.written; - if (desc.error) { - retval = retval ?: desc.error; - break; - } - if (desc.count > 0) - break; + for (seg = 0; seg < nr_segs; seg++) { + read_descriptor_t desc; + + desc.written = 0; + desc.arg.buf = iov[seg].iov_base; + desc.count = iov[seg].iov_len; + if (desc.count == 0) + continue; + desc.error = 0; + do_generic_file_read(filp, ppos, &desc, file_read_actor); + retval += desc.written; + if (desc.error) { + retval = retval ?: desc.error; + break; } + if (desc.count > 0) + break; } out: return retval;
| |