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Re: [Qemu-stable] [PATCH] nbd/trivial: fix type cast for ioctl
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From: |
Michael Tokarev |
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Subject: |
Re: [Qemu-stable] [PATCH] nbd/trivial: fix type cast for ioctl |
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Date: |
Fri, 03 Apr 2015 17:44:31 +0300 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.5.0 |
03.04.2015 17:15, Paolo Bonzini wrote:
> On 03/04/2015 13:01, Bogdan Purcareata wrote:
...
>> - if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / (size_t)BDRV_SECTOR_SIZE) <
>> 0) {
>> + if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE) <
>> 0)) {
>> int serrno = errno;
Hmm.. I don't think this is right at all. Now we compare size_t with zero,
the result is always false, and set error if ioctl return anything other than 0,
including any positive value.
Compare:
if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE) < 0))
if (ioctl(fd, NBD_SET_SIZE_BLOCKS, (size_t)(size / BDRV_SECTOR_SIZE)) < 0)
I think the latter is the right version.
So much for trivial... ;)
Thanks,
/mjt