Am 05.04.2010 16:12, schrieb Christoph Hellwig:
> Assign directly to the bdrv_flags variable instead of using
> magic numbers before translating to the BDRV_O_* options.
>
> Signed-off-by: Christoph Hellwig <h...@lst.de>
>
> Index: qemu/vl.c
> ===================================================================
> --- qemu.orig/vl.c 2010-04-05 11:05:39.042010326 +0200
> +++ qemu/vl.c 2010-04-05 11:12:18.235256380 +0200
> @@ -851,10 +851,8 @@ DriveInfo *drive_init(QemuOpts *opts, vo
> QEMUMachine *machine = opaque;
> int max_devs;
> int index;
> - int cache;
> - int aio = 0;
> int ro = 0;
> - int bdrv_flags;
> + int bdrv_flags = 0;
> int on_read_error, on_write_error;
> const char *devaddr;
> DriveInfo *dinfo;
> @@ -863,7 +861,6 @@ DriveInfo *drive_init(QemuOpts *opts, vo
> *fatal_error = 1;
>
> translation = BIOS_ATA_TRANSLATION_AUTO;
> - cache = 1;
>
> if (machine && machine->use_scsi) {
> type = IF_SCSI;
> @@ -978,11 +975,11 @@ DriveInfo *drive_init(QemuOpts *opts, vo
>
> if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
> if (!strcmp(buf, "off") || !strcmp(buf, "none"))
> - cache = 0;
> - else if (!strcmp(buf, "writethrough"))
> - cache = 1;
> + bdrv_flags |= BDRV_O_NOCACHE;
> else if (!strcmp(buf, "writeback"))
> - cache = 2;
> + bdrv_flags |= BDRV_O_CACHE_WB;
> + else if (!strcmp(buf, "writethrough"))
> + /* this is the default */;
What about following the coding style and using braces here instead of a
semicolon after the comment?
> else {
> fprintf(stderr, "qemu: invalid cache option\n");
> return NULL;
> @@ -991,10 +988,10 @@ DriveInfo *drive_init(QemuOpts *opts, vo
>
> #ifdef CONFIG_LINUX_AIO
> if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
> + if (!strcmp(buf, "native"))
> + bdrv_flags |= BDRV_O_NATIVE_AIO;
> if (!strcmp(buf, "threads"))
This needs to become an else if, breaks aio=native otherwise.
> - aio = 0;
> - else if (!strcmp(buf, "native"))
> - aio = 1;
> + /* this is the default */;
Same as above, but IMHO braces are even mandatory here as every single
line of the code is touched.
> else {
> fprintf(stderr, "qemu: invalid aio option\n");
> return NULL;
> @@ -1169,20 +1166,10 @@ DriveInfo *drive_init(QemuOpts *opts, vo
> *fatal_error = 0;
> return NULL;
> }
> - bdrv_flags = 0;
> if (snapshot) {
> - bdrv_flags |= BDRV_O_SNAPSHOT;
> - cache = 2; /* always use write-back with snapshot */
> - }
> - if (cache == 0) /* no caching */
> - bdrv_flags |= BDRV_O_NOCACHE;
> - else if (cache == 2) /* write-back */
> - bdrv_flags |= BDRV_O_CACHE_WB;
> -
> - if (aio == 1) {
> - bdrv_flags |= BDRV_O_NATIVE_AIO;
> - } else {
> - bdrv_flags &= ~BDRV_O_NATIVE_AIO;
> + /* always use write-back with snapshot */
> + bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB);
> + bdrv_flags &= ~BDRV_O_NOCACHE;
I'd prefer to have a bdrv_flags &= ~BDRV_O_CACHE_MASK before the |= line
instead of clearing some random flag that happens to be the only one.
Kevin
