* [Qemu-devel] [PATCH] cleanup block driver option handling in vl.c
@ 2010-04-05 14:12 Christoph Hellwig
2010-04-06 9:59 ` Kevin Wolf
0 siblings, 1 reply; 2+ messages in thread
From: Christoph Hellwig @ 2010-04-05 14:12 UTC (permalink / raw)
To: qemu-devel
Assign directly to the bdrv_flags variable instead of using
magic numbers before translating to the BDRV_O_* options.
Signed-off-by: Christoph Hellwig <hch@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 */;
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"))
- aio = 0;
- else if (!strcmp(buf, "native"))
- aio = 1;
+ /* this is the default */;
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;
}
if (ro == 1) {
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PATCH] cleanup block driver option handling in vl.c
2010-04-05 14:12 [Qemu-devel] [PATCH] cleanup block driver option handling in vl.c Christoph Hellwig
@ 2010-04-06 9:59 ` Kevin Wolf
0 siblings, 0 replies; 2+ messages in thread
From: Kevin Wolf @ 2010-04-06 9:59 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: qemu-devel
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 <hch@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
^ permalink raw reply [flat|nested] 2+ messages in thread
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