Date: Thu, 24 May 2001 22:36:13 -0400 From: John <jwd@bsdwins.com> To: Hackers List <freebsd-hackers@freebsd.org> Subject: sys/uio.h UIO_MAXIOV hidden inside _KERNEL Message-ID: <20010524223613.A23038@bsdwins.com>
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Hi,
Can someone provide some insight as to why UIO_MAXIOV
is hidden inside _KERNEL?
#ifdef _KERNEL
struct uio {
struct iovec *uio_iov;
int uio_iovcnt;
off_t uio_offset;
int uio_resid;
enum uio_seg uio_segflg;
enum uio_rw uio_rw;
struct proc *uio_procp;
};
/*
* Limits
*/
#define UIO_MAXIOV 1024 /* max 1K of iov's */
#define UIO_SMALLIOV 8 /* 8 on stack, else malloc */
UIO_MAXIOV is needed in userland to determine the maximum
size of the iovec array that can be sent to readv/writev.
Basically, when I get the prototypes for readv/writev, I'd
also like to get the relevant arguement size limits without
having to say I'm kernel code.
I'm iffy on whether UIO_SMALLIOV should be made visible since
it's only used in the kernel to decide how to allocate memory
prior to copy in data from the user process.
The following patch simply moves them down and adds a tad bit
of documentation:
Index: uio.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/uio.h,v
retrieving revision 1.12
diff -u -r1.12 uio.h
--- uio.h 2001/02/16 14:31:49 1.12
+++ uio.h 2001/05/25 02:32:50
@@ -68,11 +68,6 @@
struct proc *uio_procp;
};
-/*
- * Limits
- */
-#define UIO_MAXIOV 1024 /* max 1K of iov's */
-#define UIO_SMALLIOV 8 /* 8 on stack, else malloc */
struct vm_object;
@@ -91,6 +86,12 @@
ssize_t readv __P((int, const struct iovec *, int));
ssize_t writev __P((int, const struct iovec *, int));
__END_DECLS
+
+/*
+ * iovec array size limits
+ */
+#define UIO_MAXIOV 1024 /* max 1K of iov's */
+#define UIO_SMALLIOV 8 /* 8 on stack, else malloc */
#endif /* _KERNEL */
Comments?
-john
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