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make illumos uiocopy use vn_io_fault_uiomove

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uiocopy() is currently unused, its purpose is copy data from a uio
without modifying the uio.  It was in use before the vn_io_fault support
was added to ZFS, at which point our code diverged from the illumos code
a little bit.  Because ZFS is the only (potential) user of the function
we are free to modify it to better suit ZFS needs.

The intention behind this change is to remove the differences introduced
earlier in zfs_write().

While here, re-implement uioskip() using uiomove() with
uio_segflg == UIO_NOCOPY.
The story of uioskip is the same as with uiocopy.

Reviewed by:	mav
MFC after:	1 week
This commit is contained in:
Andriy Gapon 2017-11-21 18:01:43 +00:00
parent a3dff126f9
commit bf71fe61af
1 changed files with 29 additions and 49 deletions
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78
sys/cddl/compat/opensolaris/kern/opensolaris_uio.c
View File

@ -42,6 +42,7 @@
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/vnode.h>
/*
* same as uiomove() but doesn't modify uio structure.
@ -50,63 +51,42 @@
int
uiocopy(void *p, size_t n, enum uio_rw rw, struct uio *uio, size_t *cbytes)
{
struct iovec *iov;
ulong_t cnt;
int error, iovcnt;
struct iovec small_iovec[1];
struct uio small_uio_clone;
struct uio *uio_clone;
int error;
iovcnt = uio->uio_iovcnt;
*cbytes = 0;
for (iov = uio->uio_iov; n > 0 && iovcnt > 0; iov++, iovcnt--) {
cnt = MIN(iov->iov_len, n);
if (cnt == 0)
continue;
switch (uio->uio_segflg) {
case UIO_USERSPACE:
if (rw == UIO_READ)
error = copyout(p, iov->iov_base, cnt);
else
error = copyin(iov->iov_base, p, cnt);
if (error)
return (error);
break;
case UIO_SYSSPACE:
if (uio->uio_rw == UIO_READ)
bcopy(p, iov->iov_base, cnt);
else
bcopy(iov->iov_base, p, cnt);
break;
}
p = (caddr_t)p + cnt;
n -= cnt;
*cbytes += cnt;
ASSERT3U(uio->uio_rw, ==, rw);
if (uio->uio_iovcnt == 1) {
small_uio_clone = *uio;
small_iovec[0] = *uio->uio_iov;
small_uio_clone.uio_iov = small_iovec;
uio_clone = &small_uio_clone;
} else {
uio_clone = cloneuio(uio);
}
return (0);
error = vn_io_fault_uiomove(p, n, uio_clone);
*cbytes = uio->uio_resid - uio_clone->uio_resid;
if (uio_clone != &small_uio_clone)
free(uio_clone, M_IOV);
return (error);
}
/*
* Drop the next n chars out of *uiop.
*/
void
uioskip(uio_t *uiop, size_t n)
uioskip(uio_t *uio, size_t n)
{
if (n > uiop->uio_resid)
return;
while (n != 0) {
register iovec_t *iovp = uiop->uio_iov;
register size_t niovb = MIN(iovp->iov_len, n);
enum uio_seg segflg;
if (niovb == 0) {
uiop->uio_iov++;
uiop->uio_iovcnt--;
continue;
}
iovp->iov_base += niovb;
uiop->uio_loffset += niovb;
iovp->iov_len -= niovb;
uiop->uio_resid -= niovb;
n -= niovb;
}
/* For the full compatibility with illumos. */
if (n > uio->uio_resid)
return;
segflg = uio->uio_segflg;
uio->uio_segflg = UIO_NOCOPY;
uiomove(NULL, n, uio->uio_rw, uio);
uio->uio_segflg = segflg;
}