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Re: [Qemu-devel] [PATCH v2] ide: Add resize callback to ide/core
From: |
John Snow |
Subject: |
Re: [Qemu-devel] [PATCH v2] ide: Add resize callback to ide/core |
Date: |
Thu, 14 Aug 2014 12:06:25 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 |
On 08/14/2014 03:12 AM, Markus Armbruster wrote:
I'd prefer if (s->drive_kind == IDE_CFATA) ... else ..., because it
avoids the double negative.
OK. This is how cmd_identify delegates. For matters of style I usually
try to defer to nearby code.
Your code duplicates the parts of the functions initializing
s->identify_data dealing with nb_sectors. These are:
* ide_identify() for IDE_HD
Writes nb_sectors to slots 60..61 and 100..103. Matches your code.
* ide_atapi_identify() for IDE_CD
Doesn't use it at all. Your code clobbers slots 60..61 and 100.103.
Oops.
ide_resize_cb does not get called for ATAPI drives, so I think this is
not relevant. I tried to note this in a comment. See ide_init_drive:
if (kind == IDE_CD) {
bdrv_set_dev_ops(bs, &ide_cd_block_ops, s);
...
} else {
...
bdrv_set_dev_ops(bs, &ide_hd_block_ops, s);
}
* ide_cfata_identify() for IDE_CFATA
Writes nb_sectors to slots 7..8 and and 60..61. Your code only writes
the former.
...Sorry. I appreciate you taking your time to review these patches. I
will submit a V3.
I guess code duplication is tolerable, because the format of
s->identify_data is unlikely to change. Comments linking the copies
together wouldn't hurt, though.
If we don't want the duplication, we need to factor the length code out
of the identify functions, so we can use it in both places.
The length and complexity didn't feel like it needed to be factored out
into two new functions, and I liked the idea of keeping the writes to
the buffer sequential inside the initialization functions, because it
made it easier for me to read along with the spec that way. Factoring it
out seemed more of a fruitless hassle than anything.
Thanks,
--John