This is cleanup/consolidation of iovec-related low-level routines in qemu. The plan is to make library functions more understandable, consistent and useful, and to drop numerous implementations of the same thing.
The patch changes prototypes of several iov and qiov functions to match each other, changes types of arguments for some functions, _swaps_ some function arguments with each other, and makes use of common code in r/w path. The result of all these changes. 1. Most qiov-related (qemu_iovec_*) functions now accepts 'offset' parameter to specify from which (byte) position to start operation. This is added for _memset (removing _memset_skip), _from_buffer (allowing to copy a bounce- buffer to a middle of qiov). Typical: size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, int c, size_t bytes); 2. All functions that accepts this `offset' argument does it in a similar manner, following the iov, fromwhere, what, bytes pattern. This is consistent with (updated) iov_send() and iov_recv() and friends, where `offset' and `bytes' arguments were _renamed_, with the following prototypes: ssize_t iov_send(sockfd, iov, iov_cnt size_t offset, size_t bytes) instead of int qemu_sendv(sockfd, iov, int len, int iov_offset) See how offset & bytes are used in the same way as for iov_* and qemu_iovec_*. A few callers of these are verified and converted. 3. Always use iov_cnt (number of iov entries) together with iov, to be able to verify that we don't go past the array. iov_send (former qemu_sendv) and iov_recv accepts one extra argument now, as are all other derivates (qemu_co_sendv etc). 4. Used size_t instead of various variations for byte counts. Including qemu_iovec_copy which used uint64_t(!) type. 5. Function arguments are renamed to better match with their actual meaning. Compare new and original prototype of qemu_sendv() above: old prototype with `len' does not tell if `len' refers to number of iov elements (as regular writev() call) or to number of data bytes. Ditto for several usages of `count' for some qemu_iovec_*, which is also replaced to `bytes'. 5. One implementation of the code remain. For example, qemu_iovec_from_buffer() uses iov_from_buf() directly, instead of repeating the same code. The resulting function usage is much more consistent, the functions themselves are nice and understandable, which means they're easier to use and less error-prone. This patchset also consolidates a few low-level send&recv functions into one, since both versions were the same (and were finally calling common function anyway). This is done by exporting a common send_recv function with one extra bool argument, and making current send&recv to be just #defines. And while at it all, also made some implementations shorter, cleaner and much easier to read/understand, and add some code comments. The read&write consolidation has great potential for the block layer, as has been demonstrated before. Unification and generalization of qemu_iovec_* functions will let to optimize/simplify some more code in block/*, especially qemu_iovec_memset() and _from_buffer() (this optimization/simplification is already used in qcow2.c a bit). The resulting thing should behave like current/existing code, there should be no behavor changes, just some shuffling and a bit of sanity checks. It has been tested slightly, by booting different guests out of different image formats and doing some i/o, after each of the 11 patches, and it all works correctly so far. Changes since v3: - rename qemu_sendv(), qemu_sendv_recvv() to iov_send(), iov_send_recv() and move them from qemu-common.h and cutils.c to iov.h and iov.c. - add new argument, iov_cnt, to all send/recv-related functions (iov_send_recv(), qemu_co_sendv_recv() etc). This resulted in a bit more changes in other places, some of which, while simple, may still be non-obvious (block/nbd.c and block/sheepdog.c). Due to the rename above and to introduction of the new iov_cnt arg, the function signatures are changed so no old code using new function wrongly is possible. - patch that changes iov_from_buf() & iov_to_buf() is split into two halves: prototype changes and rewrite. - rewrite iov_send_recv() (former qemu_sendv_recvv()) again, slightly, to use newly introduced iov_cnt arg. Changes since v2: - covered iov.[ch] with iov_*() functions which contained similar functionality - changed tabs to spaces as per suggestion by Kevin - explicitly allow to use large sizes for frombuf/tobuf functions and friends, stopping at the end of iovec in case more bytes requested when available, and _returning_ number of actual bytes processed, but made it extra clear what a return value will be. - used ssize_t for sendv/recvv instead of int, to be consistent with all system headers and other places in qemu - fix/clarify a case in my qemu_co_sendv_recvv() of handling zero reads(recvs) and writes(sends). - covered qemu_iovec_to_buf() to have the same pattern as other too (was missing in v2), and use it in qcow2.c right away to simplify things - spotted and removed wrong usage of qiov instead of plain iov in posix-aio-compat.c What is _not_ covered: - suggestion by pbonzini to not use macros for access methods to call sendv_recvv with an extra true/false argument: I still think the usage of macros here is better than anything else. - maybe re-shuffling of all this stuff into different headers -- we already have iov.h, maybe rename it to qemu-iov.h for consistency and move all iov-related functions into there (and ditto for cutils.c => (qemu-)iov.c). Michael Tokarev (11): virtio-serial-bus: use correct lengths in control_out() message change iov_* function prototypes to be more appropriate rewrite iov_* functions consolidate qemu_iovec_memset{,_skip}() into single function and use existing iov_memset() allow qemu_iovec_from_buffer() to specify offset from which to start copying consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent change qemu_iovec_to_buf() to match other to,from_buf functions rename qemu_sendv to iov_send, change proto and move declarations to iov.h export iov_send_recv() and use it in iov_send() and iov_recv() cleanup qemu_co_sendv(), qemu_co_recvv() and friends rewrite iov_send_recv() and move it to iov.c block.c | 12 ++-- block/curl.c | 6 +- block/iscsi.c | 2 +- block/nbd.c | 16 ++-- block/qcow.c | 4 +- block/qcow2.c | 19 ++--- block/qed.c | 10 +- block/rbd.c | 2 +- block/sheepdog.c | 6 +- block/vdi.c | 4 +- cutils.c | 234 ++++++----------------------------------------- hw/9pfs/virtio-9p.c | 8 +- hw/rtl8139.c | 2 +- hw/usb/core.c | 6 +- hw/virtio-balloon.c | 4 +- hw/virtio-net.c | 4 +- hw/virtio-serial-bus.c | 10 +- iov.c | 194 +++++++++++++++++++++++++++++----------- iov.h | 77 +++++++++++++++-- linux-aio.c | 4 +- net.c | 2 +- posix-aio-compat.c | 8 +- qemu-common.h | 56 +++++------- qemu-coroutine-io.c | 83 ++++++------------ 24 files changed, 357 insertions(+), 416 deletions(-) -- 1.7.9.1