d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

In sendfile(), use the vn_rdwr() helper function, rather than manually

Browse Source 
constructing a struct aio and invoking VOP_READ() directly.  This cleans
up the code a little, but also has the advantage of making sure almost
all vnode read/write access in the kernel goes through the helper
function, meaning that instrumentation of that helper function can impact
almost all relevant read/write operations.  In this case, it permits us
to put MAC hooks into vn_rdwr() and not modify uipc_syscalls.c (yet).

In general, if helper vn_*() functions exist, they should be used in
preference to direct VOP's in system call service code.

Submitted by:	green
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
This commit is contained in:
Robert Watson 2002-04-19 13:46:24 +00:00
parent 5a06cb0ca6
commit 89e9e6e7c5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=95051
1 changed files with 4 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
sys/kern/uipc_syscalls.c
View File

@ -1779,8 +1779,6 @@ sendfile(struct thread *td, struct sendfile_args *uap)
*/
if (!pg->valid || !vm_page_is_valid(pg, pgoff, xfsize)) {
struct uio auio;
struct iovec aiov;
int bsize;
/*
@ -1793,18 +1791,11 @@ sendfile(struct thread *td, struct sendfile_args *uap)
* Get the page from backing store.
*/
bsize = vp->v_mount->mnt_stat.f_iosize;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
aiov.iov_base = 0;
aiov.iov_len = MAXBSIZE;
auio.uio_resid = MAXBSIZE;
auio.uio_offset = trunc_page(off);
auio.uio_segflg = UIO_NOCOPY;
auio.uio_rw = UIO_READ;
auio.uio_td = td;
vn_lock(vp, LK_SHARED | LK_NOPAUSE | LK_RETRY, td);
error = VOP_READ(vp, &auio, IO_VMIO | ((MAXBSIZE / bsize) << 16),
td->td_ucred);
error = vn_rdwr(UIO_READ, vp, NULL, MAXBSIZE,
trunc_page(off), UIO_NOCOPY, IO_NODELOCKED |
IO_VMIO | ((MAXBSIZE / bsize) << 16),
td->td_ucred, NULL, td);
VOP_UNLOCK(vp, 0, td);
vm_page_flag_clear(pg, PG_ZERO);
vm_page_io_finish(pg);