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Re: [Qemu-devel] [PATCH 07/10] linux-user: init_guest_space: Clean up co
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH 07/10] linux-user: init_guest_space: Clean up control flow a bit |
Date: |
Tue, 13 Mar 2018 14:30:37 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 |
Le 09/03/2018 à 21:37, Laurent Vivier a écrit :
> Le 28/12/2017 à 19:08, Luke Shumaker a écrit :
>> From: Luke Shumaker <address@hidden>
>>
>> Instead of doing
>>
>> if (check1) {
>> if (check2) {
>> success;
>> }
>> }
>>
>> retry;
>>
>> Do a clearer
>>
>> if (!check1) {
>> goto try_again;
>> }
>>
>> if (!check2) {
>> goto try_again;
>> }
>>
>> success;
>>
>> try_again:
>> retry;
>>
>> Besides being clearer, this makes it easier to insert more checks that
>> need to trigger a retry on check failure, or rearrange them, or anything
>> like that.
>>
>> Because some indentation is changing, "ignore space change" may be useful
>> for viewing this patch.
>>
>> Signed-off-by: Luke Shumaker <address@hidden>
>> ---
>> linux-user/elfload.c | 34 +++++++++++++++++++---------------
>> 1 file changed, 19 insertions(+), 15 deletions(-)
>>
>> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
>> index b560f5d6fe..5c0ad65611 100644
>> --- a/linux-user/elfload.c
>> +++ b/linux-user/elfload.c
>> @@ -1906,24 +1906,28 @@ unsigned long init_guest_space(unsigned long
>> host_start,
>> }
>>
>> /* Check to see if the address is valid. */
>> - if (!host_start || aligned_start == current_start) {
>> + if (host_start && aligned_start != current_start) {
>> + goto try_again;
>> + }
>> +
>> #if defined(TARGET_ARM) && !defined(TARGET_AARCH64)
>> - /* On 32-bit ARM, we need to also be able to map the commpage.
>> */
>> - int valid = init_guest_commpage(aligned_start - guest_start,
>> - aligned_size + guest_start);
>> - if (valid == 1) {
>> - break;
>> - } else if (valid == -1) {
>> - munmap((void *)real_start, real_size);
>> - return (unsigned long)-1;
>> - }
>> - /* valid == 0, so try again. */
>> -#else
>> - /* On other architectures, whatever we have here is fine. */
>> - break;
>> -#endif
>> + /* On 32-bit ARM, we need to also be able to map the commpage. */
>> + int valid = init_guest_commpage(aligned_start - guest_start,
>> + aligned_size + guest_start);
>> + if (valid == -1) {
>> + munmap((void *)real_start, real_size);
>> + return (unsigned long)-1;
>> + } else if (valid == -1) {
>
> I think it should be "if (valid == 0)" here.
Any comment?
Thanks,
Laurent