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[Qemu-devel] [PATCH 27/32] block: Geometry and translation hints are now


From: Markus Armbruster
Subject: [Qemu-devel] [PATCH 27/32] block: Geometry and translation hints are now useless, purge them
Date: Fri, 29 Jun 2012 17:34:49 +0200

There are two producers of these hints: drive_init() on behalf of
-drive, and hd_geometry_guess().

The only consumer of the hint is hd_geometry_guess().

The callers of hd_geometry_guess() call it only when drive_init()
didn't set the hints.  Therefore, drive_init()'s hints are never used.

Thus, hd_geometry_guess() only ever sees hints it produced itself in a
prior call.  Only the first call computes something, subsequent calls
just repeat the first call's results.  However, hd_geometry_guess() is
never called more than once: the device models don't, and the block
device is destroyed on unplug.  Thus, dropping the repeat feature
doesn't break anything now.

If a block device wasn't destroyed on unplug and could be reused with
a new device, then repeating old results would be wrong.  Thus,
dropping the repeat feature prevents future breakage.

This renders the hints unused.  Purge them from the block layer.

Signed-off-by: Markus Armbruster <address@hidden>
---
 block.c          |   32 --------------------------------
 block.h          |   12 ------------
 block_int.h      |    1 -
 blockdev.c       |   12 +-----------
 blockdev.h       |    7 +++++++
 hw/hd-geometry.c |   20 +-------------------
 6 files changed, 9 insertions(+), 75 deletions(-)

diff --git a/block.c b/block.c
index d021fd0..1eb5897 100644
--- a/block.c
+++ b/block.c
@@ -1013,12 +1013,6 @@ void bdrv_append(BlockDriverState *bs_new, 
BlockDriverState *bs_top)
     tmp.block_timer       = bs_top->block_timer;
     tmp.io_limits_enabled = bs_top->io_limits_enabled;
 
-    /* geometry */
-    tmp.cyls              = bs_top->cyls;
-    tmp.heads             = bs_top->heads;
-    tmp.secs              = bs_top->secs;
-    tmp.translation       = bs_top->translation;
-
     /* r/w error */
     tmp.on_read_error     = bs_top->on_read_error;
     tmp.on_write_error    = bs_top->on_write_error;
@@ -2103,27 +2097,6 @@ void bdrv_get_geometry(BlockDriverState *bs, uint64_t 
*nb_sectors_ptr)
     *nb_sectors_ptr = length;
 }
 
-void bdrv_set_geometry_hint(BlockDriverState *bs,
-                            int cyls, int heads, int secs)
-{
-    bs->cyls = cyls;
-    bs->heads = heads;
-    bs->secs = secs;
-}
-
-void bdrv_set_translation_hint(BlockDriverState *bs, int translation)
-{
-    bs->translation = translation;
-}
-
-void bdrv_get_geometry_hint(BlockDriverState *bs,
-                            int *pcyls, int *pheads, int *psecs)
-{
-    *pcyls = bs->cyls;
-    *pheads = bs->heads;
-    *psecs = bs->secs;
-}
-
 /* throttling disk io limits */
 void bdrv_set_io_limits(BlockDriverState *bs,
                         BlockIOLimit *io_limits)
@@ -2132,11 +2105,6 @@ void bdrv_set_io_limits(BlockDriverState *bs,
     bs->io_limits_enabled = bdrv_io_limits_enabled(bs);
 }
 
-int bdrv_get_translation_hint(BlockDriverState *bs)
-{
-    return bs->translation;
-}
-
 void bdrv_set_on_error(BlockDriverState *bs, BlockErrorAction on_read_error,
                        BlockErrorAction on_write_error)
 {
diff --git a/block.h b/block.h
index e0121d5..f02316d 100644
--- a/block.h
+++ b/block.h
@@ -256,18 +256,6 @@ int bdrv_has_zero_init(BlockDriverState *bs);
 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
                       int *pnum);
 
-#define BIOS_ATA_TRANSLATION_AUTO   0
-#define BIOS_ATA_TRANSLATION_NONE   1
-#define BIOS_ATA_TRANSLATION_LBA    2
-#define BIOS_ATA_TRANSLATION_LARGE  3
-#define BIOS_ATA_TRANSLATION_RECHS  4
-
-void bdrv_set_geometry_hint(BlockDriverState *bs,
-                            int cyls, int heads, int secs);
-void bdrv_set_translation_hint(BlockDriverState *bs, int translation);
-void bdrv_get_geometry_hint(BlockDriverState *bs,
-                            int *pcyls, int *pheads, int *psecs);
-int bdrv_get_translation_hint(BlockDriverState *bs);
 void bdrv_set_on_error(BlockDriverState *bs, BlockErrorAction on_read_error,
                        BlockErrorAction on_write_error);
 BlockErrorAction bdrv_get_on_error(BlockDriverState *bs, int is_read);
diff --git a/block_int.h b/block_int.h
index 1fb5352..d72317f 100644
--- a/block_int.h
+++ b/block_int.h
@@ -320,7 +320,6 @@ struct BlockDriverState {
 
     /* NOTE: the following infos are only hints for real hardware
        drivers. They are not used by the block driver */
-    int cyls, heads, secs, translation;
     BlockErrorAction on_read_error, on_write_error;
     bool iostatus_enabled;
     BlockDeviceIoStatus iostatus;
diff --git a/blockdev.c b/blockdev.c
index 4d3b707..37521b5 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -551,17 +551,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
     case IF_SCSI:
     case IF_XEN:
     case IF_NONE:
-        switch(media) {
-       case MEDIA_DISK:
-            if (cyls != 0) {
-                bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
-                bdrv_set_translation_hint(dinfo->bdrv, translation);
-            }
-           break;
-       case MEDIA_CDROM:
-            dinfo->media_cd = 1;
-           break;
-       }
+        dinfo->media_cd = media == MEDIA_CDROM;
         break;
     case IF_SD:
     case IF_FLOPPY:
diff --git a/blockdev.h b/blockdev.h
index 4f29c8b..b1a4bca 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -65,6 +65,13 @@ void do_commit(Monitor *mon, const QDict *qdict);
 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
 
 /* Hard disk geometry */
+
+#define BIOS_ATA_TRANSLATION_AUTO   0
+#define BIOS_ATA_TRANSLATION_NONE   1
+#define BIOS_ATA_TRANSLATION_LBA    2
+#define BIOS_ATA_TRANSLATION_LARGE  3
+#define BIOS_ATA_TRANSLATION_RECHS  4
+
 void hd_geometry_guess(BlockDriverState *bs,
                        uint32_t *pcyls, uint32_t *pheads, uint32_t *psecs,
                        int *ptrans);
diff --git a/hw/hd-geometry.c b/hw/hd-geometry.c
index 6dd5713..0e28527 100644
--- a/hw/hd-geometry.c
+++ b/hw/hd-geometry.c
@@ -113,25 +113,10 @@ void hd_geometry_guess(BlockDriverState *bs,
 {
     int cylinders, heads, secs, translation;
 
-    bdrv_get_geometry_hint(bs, &cylinders, &heads, &secs);
-    translation = bdrv_get_translation_hint(bs);
-
-    if (cylinders != 0) {
-        /* already got a geometry hint: use it */
-        *pcyls = cylinders;
-        *pheads = heads;
-        *psecs = secs;
-        if (ptrans) {
-            *ptrans = translation;
-        }
-        return;
-    }
-
-    assert(translation == BIOS_ATA_TRANSLATION_AUTO);
-
     if (guess_disk_lchs(bs, &cylinders, &heads, &secs) < 0) {
         /* no LCHS guess: use a standard physical disk geometry  */
         guess_chs_for_size(bs, pcyls, pheads, psecs);
+        translation = BIOS_ATA_TRANSLATION_AUTO;
     } else if (heads > 16) {
         /* LCHS guess with heads > 16 means that a BIOS LBA
            translation was active, so a standard physical disk
@@ -140,7 +125,6 @@ void hd_geometry_guess(BlockDriverState *bs,
         translation = *pcyls * *pheads <= 131072
             ? BIOS_ATA_TRANSLATION_LARGE
             : BIOS_ATA_TRANSLATION_LBA;
-        bdrv_set_translation_hint(bs, translation);
     } else {
         /* LCHS guess with heads <= 16: use as physical geometry */
         *pcyls = cylinders;
@@ -149,11 +133,9 @@ void hd_geometry_guess(BlockDriverState *bs,
         /* disable any translation to be in sync with
            the logical geometry */
         translation = BIOS_ATA_TRANSLATION_NONE;
-        bdrv_set_translation_hint(bs, translation);
     }
     if (ptrans) {
         *ptrans = translation;
     }
-    bdrv_set_geometry_hint(bs, *pcyls, *pheads, *psecs);
     trace_hd_geometry_guess(bs, *pcyls, *pheads, *psecs, translation);
 }
-- 
1.7.6.5




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