Re: [Qemu-devel] [PATCH 0/3] hostmem-file: make option 'size' optional

[Haozhong Zhang <haozhong.zhang@intel.com>]

On 11/07/16 08:52 +0100, Markus Armbruster wrote:
>Haozhong Zhang <haozhong.zhang@intel.com> writes:
>
>> This patch series is mostly the followup of patch 3 in
>> "[PATCH v2 0/3] Improve truncation behavior of memory-backend-file" [1][2].
>>
>> For certain usages of memory-backend-file, users simply want to use
>> the entire backend file (specified by the "mem-path" option). Therefore,
>> it's not necessary in such cases to specify the file size via the
>> "size" option. This patch series makes the "size" option of
>> memory-backend-file optional. In detail,
>>
>> 1. if the size of the backend file is not zero and the "size" option
>>    is not present, QEMU will use the file size as the "size" option;
>>
>> 2. if the backend file is a non-existing file, an empty file, or a
>>    directory, the "size" option is still needed;
>>
>> 3. the "size" option is also needed in cases that QEMU fails to the
>>    backend file size.
>
>"fails to the backend file size": are you missing a verb?
>

Yes, it should be "fails to _get_ the backend file size".

Thanks,
Haozhong

>> Patch 1 is not quite relevant. It adds missing comments on errors
>> of get_file_size() per Eduardo's suggestion.
>>
>> Patch 2 moves the file operations from file_ram_alloc() to
>> qemu_ram_alloc_from_file(), so that all checks on the file size and
>> the "size" option, and the related operations on ram block length can
>> be put in qemu_ram_alloc_from_file() and no duplication is needed.
>>
>> Patch 3 actually implements the logic to make the option "size" optional.
>>
>> [1] https://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg06823.html
>> [2] https://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg00251.html
>>
>> Haozhong Zhang (3):
>>   exec.c: add comment for errors of get_file_size()
>>   exec.c: move file operations to qemu_ram_alloc_from_file()
>>   hostmem-file: make option 'size' optional
>>
>>  backends/hostmem-file.c |  28 ++++--
>>  exec.c                  | 242 ++++++++++++++++++++++++++++++------------------
>>  2 files changed, 170 insertions(+), 100 deletions(-)