* Jay Zhou (jianjay.z...@huawei.com) wrote: > Since the commit 11808bb0c422134bf09119f4aa22c59b0ce84bf3 removed > the put_buffer callback and using an iovec based write handler instead, > the docs should be sync with the code too. > > Signed-off-by: Jay Zhou <jianjay.z...@huawei.com>
Lets check with Dan (added to cc) since he wrote 11808bb; it might be best just to rever to migration/qemu-file.h for an explanation of each function. Dave > --- > docs/devel/migration.txt | 31 ++++++++++++++++++------------- > 1 file changed, 18 insertions(+), 13 deletions(-) > > diff --git a/docs/devel/migration.txt b/docs/devel/migration.txt > index 4030703..e7b08c9 100644 > --- a/docs/devel/migration.txt > +++ b/docs/devel/migration.txt > @@ -52,26 +52,31 @@ QEMU uses a QEMUFile abstraction to be able to do > migration. Any type > of migration that wants to use QEMU infrastructure has to create a > QEMUFile with: > > -QEMUFile *qemu_fopen_ops(void *opaque, > - QEMUFilePutBufferFunc *put_buffer, > - QEMUFileGetBufferFunc *get_buffer, > - QEMUFileCloseFunc *close); > +typedef struct QEMUFileOps { > + QEMUFileGetBufferFunc *get_buffer; > + QEMUFileCloseFunc *close; > + QEMUFileSetBlocking *set_blocking; > + QEMUFileWritevBufferFunc *writev_buffer; > + QEMURetPathFunc *get_return_path; > + QEMUFileShutdownFunc *shut_down; > +} QEMUFileOps; > > -The functions have the following functionality: > +QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops); > > -This function writes a chunk of data to a file at the given position. > -The pos argument can be ignored if the file is only used for > -streaming. The handler should try to write all of the data it can. > +The main functions of QEMUFileOps have the following functionality: > > -typedef int (QEMUFilePutBufferFunc)(void *opaque, const uint8_t *buf, > - int64_t pos, int size); > +This function writes an iovec to file. The handler must write all > +of the data or return a negative errno value. > + > +typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov, > + int iovcnt, int64_t pos); > > Read a chunk of data from a file at the given position. The pos argument > can be ignored if the file is only be used for streaming. The number of > bytes actually read should be returned. > > -typedef int (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf, > - int64_t pos, int size); > +typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf, > + int64_t pos, int size); > > Close a file and return an error code. > > @@ -80,7 +85,7 @@ typedef int (QEMUFileCloseFunc)(void *opaque); > You can use any internal state that you need using the opaque void * > pointer that is passed to all functions. > > -The important functions for us are put_buffer()/get_buffer() that > +The important functions for us are writev_buffer()/get_buffer() that > allow to write/read a buffer into the QEMUFile. > > === How to save the state of one device === > -- > 1.8.3.1 > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK