From 1b093c480a32051cc856b6ab2395d8cbc3ae99da Mon Sep 17 00:00:00 2001 From: Michael Tokarev Date: Mon, 12 Mar 2012 21:28:06 +0400 Subject: consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent qemu_iovec_concat() is currently a wrapper for qemu_iovec_copy(), use the former (with extra "0" arg) in a few places where it is used. Change skip argument of qemu_iovec_copy() from uint64_t to size_t, since size of qiov itself is size_t, so there's no way to skip larger sizes. Rename it to soffset, to make it clear that the offset is applied to src. Also change the only usage of uint64_t in hw/9pfs/virtio-9p.c, in v9fs_init_qiov_from_pdu() - all callers of it actually uses size_t too, not uint64_t. One added restriction: as for all other iovec-related functions, soffset must point inside src. Order of argumens is already good: qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, int c, size_t bytes) vs: qemu_iovec_concat(QEMUIOVector *dst, QEMUIOVector *src, size_t soffset, size_t sbytes) (note soffset is after _src_ not dst, since it applies to src; for memset it applies to qiov). Note that in many places where this function is used, the previous call is qemu_iovec_reset(), which means many callers actually want copy (replacing dst content), not concat. So we may want to add a wrapper like qemu_iovec_copy() with the same arguments but which calls qemu_iovec_reset() before _concat(). Signed-off-by: Michael Tokarev --- cutils.c | 54 ++++++++++++++++++++---------------------------------- 1 file changed, 20 insertions(+), 34 deletions(-) (limited to 'cutils.c') diff --git a/cutils.c b/cutils.c index b4dd844644..1aeac153ad 100644 --- a/cutils.c +++ b/cutils.c @@ -172,48 +172,34 @@ void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) } /* - * Copies iovecs from src to the end of dst. It starts copying after skipping - * the given number of bytes in src and copies until src is completely copied - * or the total size of the copied iovec reaches size.The size of the last - * copied iovec is changed in order to fit the specified total size if it isn't - * a perfect fit already. + * Concatenates (partial) iovecs from src to the end of dst. + * It starts copying after skipping `soffset' bytes at the + * beginning of src and adds individual vectors from src to + * dst copies up to `sbytes' bytes total, or up to the end + * of src if it comes first. This way, it is okay to specify + * very large value for `sbytes' to indicate "up to the end + * of src". + * Only vector pointers are processed, not the actual data buffers. */ -void qemu_iovec_copy(QEMUIOVector *dst, QEMUIOVector *src, uint64_t skip, - size_t size) +void qemu_iovec_concat(QEMUIOVector *dst, + QEMUIOVector *src, size_t soffset, size_t sbytes) { int i; size_t done; - void *iov_base; - uint64_t iov_len; - + struct iovec *siov = src->iov; assert(dst->nalloc != -1); - - done = 0; - for (i = 0; (i < src->niov) && (done != size); i++) { - if (skip >= src->iov[i].iov_len) { - /* Skip the whole iov */ - skip -= src->iov[i].iov_len; - continue; + assert(src->size >= soffset); + for (i = 0, done = 0; done < sbytes && i < src->niov; i++) { + if (soffset < siov[i].iov_len) { + size_t len = MIN(siov[i].iov_len - soffset, sbytes - done); + qemu_iovec_add(dst, siov[i].iov_base + soffset, len); + done += len; + soffset = 0; } else { - /* Skip only part (or nothing) of the iov */ - iov_base = (uint8_t*) src->iov[i].iov_base + skip; - iov_len = src->iov[i].iov_len - skip; - skip = 0; + soffset -= siov[i].iov_len; } - - if (done + iov_len > size) { - qemu_iovec_add(dst, iov_base, size - done); - break; - } else { - qemu_iovec_add(dst, iov_base, iov_len); - } - done += iov_len; } -} - -void qemu_iovec_concat(QEMUIOVector *dst, QEMUIOVector *src, size_t size) -{ - qemu_iovec_copy(dst, src, 0, size); + /* return done; */ } void qemu_iovec_destroy(QEMUIOVector *qiov) -- cgit v1.2.3