Re: [PATCH v4 2/3] Add preadv and pwritev system calls.

From: Gerd Hoffmann
Date: Thu Dec 18 2008 - 08:38:20 EST


Hi,

> Please remember to add the function prototypes to
> include/linux/syscalls.h.

Done.

>> +asmlinkage ssize_t
>> +compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec,
>> + unsigned long vlen, u32 pos_high, u32 pos_low)
>> +{.
>> + loff_t pos = ((loff_t)pos_high << 32) | pos_low;
>
> This is whitespace damaged, as are the other four functions in the
> same place.

Fixed.

>> + struct file *file;
>> + ssize_t ret = -EBADF;
>> +
>> + if (pos < 0)
>> + return -EINVAL;
>> +
>> + file = fget(fd);
>> + if (!file)
>> + return -EBADF;
>
> Any reason for using fget() here, but fget_light() in sys_preadv?

Due to the new syscalls being derived from the readv()/preadv()
versions, which have the same inconsistency. Dunno why. I'd suspect
the reason is that the compat syscalls tend to be overlooked when the
code is updated. Proof: patch #1 in this series ...

I'll switch them all over in a separate followup patch.

>> + if (!(file->f_mode & FMODE_READ))
>> + goto out;
>> +
>> + ret = -EINVAL;
>> + if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
>> + goto out;
>
> Maybe this logic could get moved into a compat_readv() function,
> similar to vfs_readv().

Yes, makes sense.

cheers,
Gerd


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