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More fixes from bde.

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Only modify times on success.
	splhigh() around time variable usage.
	Make atomic writes more posix compliant.
	Spelling errors.
Submitted by:	bde
This commit is contained in:
John Dyson 1996-02-05 05:50:34 +00:00
parent 96cc6b1011
commit f29e1bd629
1 changed files with 24 additions and 14 deletions
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38
sys/kern/sys_pipe.c
View File

@ -40,7 +40,7 @@
* process.
*
* If the sending process receives a signal, it is possible that it will
* go away, and certainly it's address space can change, because control
* go away, and certainly its address space can change, because control
* is returned back to the user-mode side. In that case, the pipe code
* arranges to copy the buffer supplied by the user process, to a pageable
* kernel buffer, and the receiving process will grab the data from the
@ -49,7 +49,7 @@
*
* The constant PIPE_MINDIRECT is chosen to make sure that buffering will
* happen for small transfers so that the system will not spend all of
* it's time context switching. PIPE_SIZE is constrained by the
* its time context switching. PIPE_SIZE is constrained by the
* amount of kernel virtual memory.
*/
@ -223,6 +223,7 @@ static void
pipeinit(cpipe)
struct pipe *cpipe;
{
int s;
cpipe->pipe_buffer.in = 0;
cpipe->pipe_buffer.out = 0;
@ -234,9 +235,11 @@ pipeinit(cpipe)
cpipe->pipe_state = 0;
cpipe->pipe_peer = NULL;
cpipe->pipe_busy = 0;
s = splhigh();
cpipe->pipe_ctime = time;
cpipe->pipe_atime = time;
cpipe->pipe_mtime = time;
splx(s);
bzero(&cpipe->pipe_sel, sizeof cpipe->pipe_sel);
/*
@ -340,7 +343,6 @@ pipe_read(fp, uio, cred)
rpipe->pipe_buffer.cnt -= size;
nread += size;
rpipe->pipe_atime = time;
/*
* Direct copy, bypassing a kernel buffer.
*/
@ -357,7 +359,6 @@ pipe_read(fp, uio, cred)
if (error)
break;
nread += size;
rpipe->pipe_atime = time;
rpipe->pipe_map.pos += size;
rpipe->pipe_map.cnt -= size;
if (rpipe->pipe_map.cnt == 0) {
@ -387,7 +388,7 @@ pipe_read(fp, uio, cred)
/*
* If there is no more to read in the pipe, reset
* it's pointers to the beginning. This improves
* its pointers to the beginning. This improves
* cache hit stats.
*/
@ -407,6 +408,12 @@ pipe_read(fp, uio, cred)
}
}
if (error == 0) {
int s = splhigh();
rpipe->pipe_atime = time;
splx(s);
}
--rpipe->pipe_busy;
if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) {
rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW);
@ -414,7 +421,7 @@ pipe_read(fp, uio, cred)
} else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) {
/*
* If there is no more to read in the pipe, reset
* it's pointers to the beginning. This improves
* its pointers to the beginning. This improves
* cache hit stats.
*/
if ((error == 0) && (error = pipelock(rpipe,1)) == 0) {
@ -645,6 +652,7 @@ pipewrite(wpipe, uio, nbio)
int nbio;
{
int error = 0;
int orig_resid;
/*
* detect loss of pipe read side, issue SIGPIPE if lost.
@ -663,6 +671,7 @@ pipewrite(wpipe, uio, nbio)
}
++wpipe->pipe_busy;
orig_resid = uio->uio_resid;
while (uio->uio_resid) {
int space;
/*
@ -693,13 +702,14 @@ pipewrite(wpipe, uio, nbio)
}
space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF))
space = 0;
/*
* We must afford contiguous writes on buffers of size
* PIPE_BUF or less.
*/
if ((space > 0) &&
((uio->uio_resid > PIPE_BUF) || (uio->uio_resid <= space))) {
if (space > 0) {
int size = wpipe->pipe_buffer.size - wpipe->pipe_buffer.in;
if (size > space)
size = space;
@ -726,7 +736,6 @@ pipewrite(wpipe, uio, nbio)
wpipe->pipe_buffer.in = 0;
wpipe->pipe_buffer.cnt += size;
wpipe->pipe_mtime = time;
} else {
/*
* If the "read-side" has been blocked, wake it up now.
@ -780,6 +789,12 @@ pipewrite(wpipe, uio, nbio)
(uio->uio_resid == 0) &&
(error == EPIPE))
error = 0;
if (error = 0) {
int s = splhigh();
wpipe->pipe_mtime = time;
splx(s);
}
if (wpipe->pipe_state & PIPE_SEL) {
wpipe->pipe_state &= ~PIPE_SEL;
@ -855,7 +870,6 @@ pipe_select(fp, which, p)
{
register struct pipe *rpipe = (struct pipe *)fp->f_data;
struct pipe *wpipe;
register int s = splnet();
wpipe = rpipe->pipe_peer;
switch (which) {
@ -863,7 +877,6 @@ pipe_select(fp, which, p)
case FREAD:
if (rpipe->pipe_buffer.cnt > 0 ||
(rpipe->pipe_state & PIPE_EOF)) {
splx(s);
return (1);
}
selrecord(p, &rpipe->pipe_sel);
@ -874,7 +887,6 @@ pipe_select(fp, which, p)
if ((wpipe == NULL) ||
(wpipe->pipe_state & PIPE_EOF) ||
((wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) {
splx(s);
return (1);
}
selrecord(p, &wpipe->pipe_sel);
@ -885,7 +897,6 @@ pipe_select(fp, which, p)
if ((rpipe->pipe_state & PIPE_EOF) ||
(wpipe == NULL) ||
(wpipe->pipe_state & PIPE_EOF)) {
splx(s);
return (1);
}
@ -893,7 +904,6 @@ pipe_select(fp, which, p)
rpipe->pipe_state |= PIPE_SEL;
break;
}
splx(s);
return (0);
}