Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v4 2/3] Add preadv and pwritev system calls. | Date | Thu, 18 Dec 2008 13:34:33 +0100 |
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On Thursday 18 December 2008, Gerd Hoffmann wrote: > This prototype has one problem though: On 32bit archs is the (64bit) > offset argument unaligned, which the syscall ABI of several archs > doesn't allow to do. At least s390 needs a wrapper in glibc to handle > this. As we'll need a wrappers in glibc anyway I've decided to push > problem to glibc entriely and use a syscall prototype which works > without arch-specific wrappers inside the kernel: The offset argument > is explicitly splitted into two 32bit values.
Obviously, the interface looks good to me now.
Please remember to add the function prototypes to include/linux/syscalls.h.
> +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.
> + 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?
> + 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(). The advantage would be that we can make the native and compat paths more similar.
Arnd <><
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