PERFORCE change 162939 for review
Zhao Shuai
zhaoshuai at FreeBSD.org
Thu May 28 12:52:43 UTC 2009
http://perforce.freebsd.org/chv.cgi?CH=162939
Change 162939 by zhaoshuai at zhaoshuai on 2009/05/28 12:51:57
split pipe code into subr_pipe.c, haven't compiled it
Affected files ...
.. //depot/projects/soc2009/fifo/sys/kern/subr_pipe.c#1 add
.. //depot/projects/soc2009/fifo/sys/kern/sys_pipe.c#4 edit
Differences ...
==== //depot/projects/soc2009/fifo/sys/kern/sys_pipe.c#4 (text+ko) ====
@@ -17,81 +17,7 @@
* are met.
*/
-/*
- * This file contains a high-performance replacement for the socket-based
- * pipes scheme originally used in FreeBSD/4.4Lite. It does not support
- * all features of sockets, but does do everything that pipes normally
- * do.
- */
-
-/*
- * This code has two modes of operation, a small write mode and a large
- * write mode. The small write mode acts like conventional pipes with
- * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the
- * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT
- * and PIPE_SIZE in size, it is fully mapped and wired into the kernel, and
- * the receiving process can copy it directly from the pages in the sending
- * process.
- *
- * If the sending process receives a signal, it is possible that it will
- * 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
- * pageable kernel buffer. Since signals don't happen all that often,
- * the copy operation is normally eliminated.
- *
- * 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
- * its time context switching.
- *
- * In order to limit the resource use of pipes, two sysctls exist:
- *
- * kern.ipc.maxpipekva - This is a hard limit on the amount of pageable
- * address space available to us in pipe_map. This value is normally
- * autotuned, but may also be loader tuned.
- *
- * kern.ipc.pipekva - This read-only sysctl tracks the current amount of
- * memory in use by pipes.
- *
- * Based on how large pipekva is relative to maxpipekva, the following
- * will happen:
- *
- * 0% - 50%:
- * New pipes are given 16K of memory backing, pipes may dynamically
- * grow to as large as 64K where needed.
- * 50% - 75%:
- * New pipes are given 4K (or PAGE_SIZE) of memory backing,
- * existing pipes may NOT grow.
- * 75% - 100%:
- * New pipes are given 4K (or PAGE_SIZE) of memory backing,
- * existing pipes will be shrunk down to 4K whenever possible.
- *
- * Resizing may be disabled by setting kern.ipc.piperesizeallowed=0. If
- * that is set, the only resize that will occur is the 0 -> SMALL_PIPE_SIZE
- * resize which MUST occur for reverse-direction pipes when they are
- * first used.
- *
- * Additional information about the current state of pipes may be obtained
- * from kern.ipc.pipes, kern.ipc.pipefragretry, kern.ipc.pipeallocfail,
- * and kern.ipc.piperesizefail.
- *
- * Locking rules: There are two locks present here: A mutex, used via
- * PIPE_LOCK, and a flag, used via pipelock(). All locking is done via
- * the flag, as mutexes can not persist over uiomove. The mutex
- * exists only to guard access to the flag, and is not in itself a
- * locking mechanism. Also note that there is only a single mutex for
- * both directions of a pipe.
- *
- * As pipelock() may have to sleep before it can acquire the flag, it
- * is important to reread all data after a call to pipelock(); everything
- * in the structure may have changed.
- */
-
#include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/sys/kern/sys_pipe.c,v 1.201 2009/03/10 21:28:43 jhb Exp $");
-
-#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
@@ -101,8 +27,6 @@
#include <sys/filio.h>
#include <sys/kernel.h>
#include <sys/lock.h>
-#include <sys/mutex.h>
-#include <sys/ttycom.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/poll.h>
@@ -117,33 +41,11 @@
#include <sys/uio.h>
#include <sys/event.h>
-#include <security/mac/mac_framework.h>
-
-#include <vm/vm.h>
-#include <vm/vm_param.h>
-#include <vm/vm_object.h>
-#include <vm/vm_kern.h>
-#include <vm/vm_extern.h>
-#include <vm/pmap.h>
-#include <vm/vm_map.h>
-#include <vm/vm_page.h>
-#include <vm/uma.h>
-
-/*
- * Use this define if you want to disable *fancy* VM things. Expect an
- * approx 30% decrease in transfer rate. This could be useful for
- * NetBSD or OpenBSD.
- */
-/* #define PIPE_NODIRECT */
-
/*
* interfaces to the outside world
- * pipe_read and pipe_write is no longer static, they are used by FIFO
*/
-/*
-fo_rdwr_t pipe_read;
-fo_rdwr_t pipe_write;
-*/
+static fo_rdwr_t pipe_read;
+static fo_rdwr_t pipe_write;
static fo_truncate_t pipe_truncate;
static fo_ioctl_t pipe_ioctl;
static fo_poll_t pipe_poll;
@@ -163,153 +65,7 @@
.fo_flags = DFLAG_PASSABLE
};
-static void filt_pipedetach(struct knote *kn);
-static int filt_piperead(struct knote *kn, long hint);
-static int filt_pipewrite(struct knote *kn, long hint);
-
-static struct filterops pipe_rfiltops =
- { 1, NULL, filt_pipedetach, filt_piperead };
-static struct filterops pipe_wfiltops =
- { 1, NULL, filt_pipedetach, filt_pipewrite };
-
-/*
- * Default pipe buffer size(s), this can be kind-of large now because pipe
- * space is pageable. The pipe code will try to maintain locality of
- * reference for performance reasons, so small amounts of outstanding I/O
- * will not wipe the cache.
- */
-#define MINPIPESIZE (PIPE_SIZE/3)
-#define MAXPIPESIZE (2*PIPE_SIZE/3)
-
-static long amountpipekva;
-static int pipefragretry;
-static int pipeallocfail;
-static int piperesizefail;
-static int piperesizeallowed = 1;
-
-SYSCTL_LONG(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RDTUN,
- &maxpipekva, 0, "Pipe KVA limit");
-SYSCTL_LONG(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD,
- &amountpipekva, 0, "Pipe KVA usage");
-SYSCTL_INT(_kern_ipc, OID_AUTO, pipefragretry, CTLFLAG_RD,
- &pipefragretry, 0, "Pipe allocation retries due to fragmentation");
-SYSCTL_INT(_kern_ipc, OID_AUTO, pipeallocfail, CTLFLAG_RD,
- &pipeallocfail, 0, "Pipe allocation failures");
-SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizefail, CTLFLAG_RD,
- &piperesizefail, 0, "Pipe resize failures");
-SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizeallowed, CTLFLAG_RW,
- &piperesizeallowed, 0, "Pipe resizing allowed");
-
-static void pipeinit(void *dummy __unused);
/*
-static void pipeclose(struct pipe *cpipe);
-*/
-static void pipe_free_kmem(struct pipe *cpipe);
-static int pipe_create(struct pipe *pipe, int backing);
-static __inline int pipelock(struct pipe *cpipe, int catch);
-static __inline void pipeunlock(struct pipe *cpipe);
-static __inline void pipeselwakeup(struct pipe *cpipe);
-#ifndef PIPE_NODIRECT
-static int pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio);
-static void pipe_destroy_write_buffer(struct pipe *wpipe);
-static int pipe_direct_write(struct pipe *wpipe, struct uio *uio);
-static void pipe_clone_write_buffer(struct pipe *wpipe);
-#endif
-static int pipespace(struct pipe *cpipe, int size);
-static int pipespace_new(struct pipe *cpipe, int size);
-
-static int pipe_zone_ctor(void *mem, int size, void *arg, int flags);
-static int pipe_zone_init(void *mem, int size, int flags);
-static void pipe_zone_fini(void *mem, int size);
-
-static uma_zone_t pipe_zone;
-
-SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL);
-
-static void
-pipeinit(void *dummy __unused)
-{
-
- pipe_zone = uma_zcreate("pipe", sizeof(struct pipepair),
- pipe_zone_ctor, NULL, pipe_zone_init, pipe_zone_fini,
- UMA_ALIGN_PTR, 0);
- KASSERT(pipe_zone != NULL, ("pipe_zone not initialized"));
-}
-
-static int
-pipe_zone_ctor(void *mem, int size, void *arg, int flags)
-{
- struct pipepair *pp;
- struct pipe *rpipe, *wpipe;
-
- KASSERT(size == sizeof(*pp), ("pipe_zone_ctor: wrong size"));
-
- pp = (struct pipepair *)mem;
-
- /*
- * We zero both pipe endpoints to make sure all the kmem pointers
- * are NULL, flag fields are zero'd, etc. We timestamp both
- * endpoints with the same time.
- */
- rpipe = &pp->pp_rpipe;
- bzero(rpipe, sizeof(*rpipe));
- vfs_timestamp(&rpipe->pipe_ctime);
- rpipe->pipe_atime = rpipe->pipe_mtime = rpipe->pipe_ctime;
-
- wpipe = &pp->pp_wpipe;
- bzero(wpipe, sizeof(*wpipe));
- wpipe->pipe_ctime = rpipe->pipe_ctime;
- wpipe->pipe_atime = wpipe->pipe_mtime = rpipe->pipe_ctime;
-
- rpipe->pipe_peer = wpipe;
- rpipe->pipe_pair = pp;
- wpipe->pipe_peer = rpipe;
- wpipe->pipe_pair = pp;
-
- /*
- * Mark both endpoints as present; they will later get free'd
- * one at a time. When both are free'd, then the whole pair
- * is released.
- */
- rpipe->pipe_present = PIPE_ACTIVE;
- wpipe->pipe_present = PIPE_ACTIVE;
-
- /*
- * Eventually, the MAC Framework may initialize the label
- * in ctor or init, but for now we do it elswhere to avoid
- * blocking in ctor or init.
- */
- pp->pp_label = NULL;
-
- return (0);
-}
-
-static int
-pipe_zone_init(void *mem, int size, int flags)
-{
- struct pipepair *pp;
-
- KASSERT(size == sizeof(*pp), ("pipe_zone_init: wrong size"));
-
- pp = (struct pipepair *)mem;
-
- mtx_init(&pp->pp_mtx, "pipe mutex", NULL, MTX_DEF | MTX_RECURSE);
- return (0);
-}
-
-static void
-pipe_zone_fini(void *mem, int size)
-{
- struct pipepair *pp;
-
- KASSERT(size == sizeof(*pp), ("pipe_zone_fini: wrong size"));
-
- pp = (struct pipepair *)mem;
-
- mtx_destroy(&pp->pp_mtx);
-}
-
-/*
* The pipe system call for the DTYPE_PIPE type of pipes. If we fail, let
* the zone pick up the pieces via pipeclose().
*/
@@ -319,42 +75,15 @@
struct filedesc *fdp = td->td_proc->p_fd;
struct file *rf, *wf;
struct pipepair *pp;
- struct pipe *rpipe, *wpipe;
int fd, error;
- pp = uma_zalloc(pipe_zone, M_WAITOK);
-#ifdef MAC
- /*
- * The MAC label is shared between the connected endpoints. As a
- * result mac_pipe_init() and mac_pipe_create() are called once
- * for the pair, and not on the endpoints.
- */
- mac_pipe_init(pp);
- mac_pipe_create(td->td_ucred, pp);
-#endif
- rpipe = &pp->pp_rpipe;
- wpipe = &pp->pp_wpipe;
-
- knlist_init(&rpipe->pipe_sel.si_note, PIPE_MTX(rpipe), NULL, NULL,
- NULL);
- knlist_init(&wpipe->pipe_sel.si_note, PIPE_MTX(wpipe), NULL, NULL,
- NULL);
-
- /* Only the forward direction pipe is backed by default */
- if ((error = pipe_create(rpipe, 1)) != 0 ||
- (error = pipe_create(wpipe, 0)) != 0) {
- pipeclose(rpipe);
- pipeclose(wpipe);
- return (error);
- }
-
- rpipe->pipe_state |= PIPE_DIRECTOK;
- wpipe->pipe_state |= PIPE_DIRECTOK;
+ if ((error = generic_pipe_create(&pp, td)) != 0)
+ return (error);
error = falloc(td, &rf, &fd);
if (error) {
- pipeclose(rpipe);
- pipeclose(wpipe);
+ pipeclose(&pp->rpipe);
+ pipeclose(&pp->wpipe);
return (error);
}
/* An extra reference on `rf' has been held for us by falloc(). */
@@ -366,17 +95,17 @@
* to avoid races against processes which manage to dup() the read
* side while we are blocked trying to allocate the write side.
*/
- finit(rf, FREAD | FWRITE, DTYPE_PIPE, rpipe, &pipeops);
+ finit(rf, FREAD | FWRITE, DTYPE_PIPE, &pp->rpipe, &pipeops);
error = falloc(td, &wf, &fd);
if (error) {
fdclose(fdp, rf, fildes[0], td);
fdrop(rf, td);
/* rpipe has been closed by fdrop(). */
- pipeclose(wpipe);
+ pipeclose(&pp->wpipe);
return (error);
}
/* An extra reference on `wf' has been held for us by falloc(). */
- finit(wf, FREAD | FWRITE, DTYPE_PIPE, wpipe, &pipeops);
+ finit(wf, FREAD | FWRITE, DTYPE_PIPE, &pp->wpipe, &pipeops);
fdrop(wf, td);
fildes[1] = fd;
fdrop(rf, td);
@@ -401,1048 +130,53 @@
return (0);
}
-/*
- * Allocate kva for pipe circular buffer, the space is pageable
- * This routine will 'realloc' the size of a pipe safely, if it fails
- * it will retain the old buffer.
- * If it fails it will return ENOMEM.
- */
-static int
-pipespace_new(cpipe, size)
- struct pipe *cpipe;
- int size;
-{
- caddr_t buffer;
- int error, cnt, firstseg;
- static int curfail = 0;
- static struct timeval lastfail;
-
- KASSERT(!mtx_owned(PIPE_MTX(cpipe)), ("pipespace: pipe mutex locked"));
- KASSERT(!(cpipe->pipe_state & PIPE_DIRECTW),
- ("pipespace: resize of direct writes not allowed"));
-retry:
- cnt = cpipe->pipe_buffer.cnt;
- if (cnt > size)
- size = cnt;
-
- size = round_page(size);
- buffer = (caddr_t) vm_map_min(pipe_map);
-
- error = vm_map_find(pipe_map, NULL, 0,
- (vm_offset_t *) &buffer, size, 1,
- VM_PROT_ALL, VM_PROT_ALL, 0);
- if (error != KERN_SUCCESS) {
- if ((cpipe->pipe_buffer.buffer == NULL) &&
- (size > SMALL_PIPE_SIZE)) {
- size = SMALL_PIPE_SIZE;
- pipefragretry++;
- goto retry;
- }
- if (cpipe->pipe_buffer.buffer == NULL) {
- pipeallocfail++;
- if (ppsratecheck(&lastfail, &curfail, 1))
- printf("kern.ipc.maxpipekva exceeded; see tuning(7)\n");
- } else {
- piperesizefail++;
- }
- return (ENOMEM);
- }
-
- /* copy data, then free old resources if we're resizing */
- if (cnt > 0) {
- if (cpipe->pipe_buffer.in <= cpipe->pipe_buffer.out) {
- firstseg = cpipe->pipe_buffer.size - cpipe->pipe_buffer.out;
- bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out],
- buffer, firstseg);
- if ((cnt - firstseg) > 0)
- bcopy(cpipe->pipe_buffer.buffer, &buffer[firstseg],
- cpipe->pipe_buffer.in);
- } else {
- bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out],
- buffer, cnt);
- }
- }
- pipe_free_kmem(cpipe);
- cpipe->pipe_buffer.buffer = buffer;
- cpipe->pipe_buffer.size = size;
- cpipe->pipe_buffer.in = cnt;
- cpipe->pipe_buffer.out = 0;
- cpipe->pipe_buffer.cnt = cnt;
- atomic_add_long(&amountpipekva, cpipe->pipe_buffer.size);
- return (0);
-}
-
-/*
- * Wrapper for pipespace_new() that performs locking assertions.
- */
-static int
-pipespace(cpipe, size)
- struct pipe *cpipe;
- int size;
-{
-
- KASSERT(cpipe->pipe_state & PIPE_LOCKFL,
- ("Unlocked pipe passed to pipespace"));
- return (pipespace_new(cpipe, size));
-}
-
-/*
- * lock a pipe for I/O, blocking other access
- */
-static __inline int
-pipelock(cpipe, catch)
- struct pipe *cpipe;
- int catch;
-{
- int error;
-
- PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
- while (cpipe->pipe_state & PIPE_LOCKFL) {
- cpipe->pipe_state |= PIPE_LWANT;
- error = msleep(cpipe, PIPE_MTX(cpipe),
- catch ? (PRIBIO | PCATCH) : PRIBIO,
- "pipelk", 0);
- if (error != 0)
- return (error);
- }
- cpipe->pipe_state |= PIPE_LOCKFL;
- return (0);
-}
-
-/*
- * unlock a pipe I/O lock
- */
-static __inline void
-pipeunlock(cpipe)
- struct pipe *cpipe;
-{
-
- PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
- KASSERT(cpipe->pipe_state & PIPE_LOCKFL,
- ("Unlocked pipe passed to pipeunlock"));
- cpipe->pipe_state &= ~PIPE_LOCKFL;
- if (cpipe->pipe_state & PIPE_LWANT) {
- cpipe->pipe_state &= ~PIPE_LWANT;
- wakeup(cpipe);
- }
-}
-
-static __inline void
-pipeselwakeup(cpipe)
- struct pipe *cpipe;
-{
-
- PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
- if (cpipe->pipe_state & PIPE_SEL) {
- selwakeuppri(&cpipe->pipe_sel, PSOCK);
- if (!SEL_WAITING(&cpipe->pipe_sel))
- cpipe->pipe_state &= ~PIPE_SEL;
- }
- if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio)
- pgsigio(&cpipe->pipe_sigio, SIGIO, 0);
- KNOTE_LOCKED(&cpipe->pipe_sel.si_note, 0);
-}
-
-/*
- * Initialize and allocate VM and memory for pipe. The structure
- * will start out zero'd from the ctor, so we just manage the kmem.
- */
-static int
-pipe_create(pipe, backing)
- struct pipe *pipe;
- int backing;
-{
- int error;
-
- if (backing) {
- if (amountpipekva > maxpipekva / 2)
- error = pipespace_new(pipe, SMALL_PIPE_SIZE);
- else
- error = pipespace_new(pipe, PIPE_SIZE);
- } else {
- /* If we're not backing this pipe, no need to do anything. */
- error = 0;
- }
- return (error);
-}
-
-/* ARGSUSED */
int
-pipe_read(fp, uio, active_cred, flags, td)
- struct file *fp;
- struct uio *uio;
- struct ucred *active_cred;
- struct thread *td;
- int flags;
+pipe_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
+ struct thread *td)
{
- struct pipe *rpipe = fp->f_data;
- int error;
- int nread = 0;
- u_int size;
- PIPE_LOCK(rpipe);
- ++rpipe->pipe_busy;
- error = pipelock(rpipe, 1);
- if (error)
- goto unlocked_error;
-
-#ifdef MAC
- error = mac_pipe_check_read(active_cred, rpipe->pipe_pair);
- if (error)
- goto locked_error;
-#endif
- if (amountpipekva > (3 * maxpipekva) / 4) {
- if (!(rpipe->pipe_state & PIPE_DIRECTW) &&
- (rpipe->pipe_buffer.size > SMALL_PIPE_SIZE) &&
- (rpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) &&
- (piperesizeallowed == 1)) {
- PIPE_UNLOCK(rpipe);
- pipespace(rpipe, SMALL_PIPE_SIZE);
- PIPE_LOCK(rpipe);
- }
- }
-
- while (uio->uio_resid) {
- /*
- * normal pipe buffer receive
- */
- if (rpipe->pipe_buffer.cnt > 0) {
- size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out;
- if (size > rpipe->pipe_buffer.cnt)
- size = rpipe->pipe_buffer.cnt;
- if (size > (u_int) uio->uio_resid)
- size = (u_int) uio->uio_resid;
-
- PIPE_UNLOCK(rpipe);
- error = uiomove(
- &rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out],
- size, uio);
- PIPE_LOCK(rpipe);
- if (error)
- break;
-
- rpipe->pipe_buffer.out += size;
- if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size)
- rpipe->pipe_buffer.out = 0;
-
- rpipe->pipe_buffer.cnt -= size;
-
- /*
- * If there is no more to read in the pipe, reset
- * its pointers to the beginning. This improves
- * cache hit stats.
- */
- if (rpipe->pipe_buffer.cnt == 0) {
- rpipe->pipe_buffer.in = 0;
- rpipe->pipe_buffer.out = 0;
- }
- nread += size;
-#ifndef PIPE_NODIRECT
- /*
- * Direct copy, bypassing a kernel buffer.
- */
- } else if ((size = rpipe->pipe_map.cnt) &&
- (rpipe->pipe_state & PIPE_DIRECTW)) {
- if (size > (u_int) uio->uio_resid)
- size = (u_int) uio->uio_resid;
-
- PIPE_UNLOCK(rpipe);
- error = uiomove_fromphys(rpipe->pipe_map.ms,
- rpipe->pipe_map.pos, size, uio);
- PIPE_LOCK(rpipe);
- if (error)
- break;
- nread += size;
- rpipe->pipe_map.pos += size;
- rpipe->pipe_map.cnt -= size;
- if (rpipe->pipe_map.cnt == 0) {
- rpipe->pipe_state &= ~PIPE_DIRECTW;
- wakeup(rpipe);
- }
-#endif
- } else {
- /*
- * detect EOF condition
- * read returns 0 on EOF, no need to set error
- */
- if (rpipe->pipe_state & PIPE_EOF)
- break;
-
- /*
- * If the "write-side" has been blocked, wake it up now.
- */
- if (rpipe->pipe_state & PIPE_WANTW) {
- rpipe->pipe_state &= ~PIPE_WANTW;
- wakeup(rpipe);
- }
-
- /*
- * Break if some data was read.
- */
- if (nread > 0)
- break;
-
- /*
- * Unlock the pipe buffer for our remaining processing.
- * We will either break out with an error or we will
- * sleep and relock to loop.
- */
- pipeunlock(rpipe);
-
- /*
- * Handle non-blocking mode operation or
- * wait for more data.
- */
- if (fp->f_flag & FNONBLOCK) {
- error = EAGAIN;
- } else {
- rpipe->pipe_state |= PIPE_WANTR;
- if ((error = msleep(rpipe, PIPE_MTX(rpipe),
- PRIBIO | PCATCH,
- "piperd", 0)) == 0)
- error = pipelock(rpipe, 1);
- }
- if (error)
- goto unlocked_error;
- }
- }
-#ifdef MAC
-locked_error:
-#endif
- pipeunlock(rpipe);
-
- /* XXX: should probably do this before getting any locks. */
- if (error == 0)
- vfs_timestamp(&rpipe->pipe_atime);
-unlocked_error:
- --rpipe->pipe_busy;
-
- /*
- * PIPE_WANT processing only makes sense if pipe_busy is 0.
- */
- if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) {
- rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW);
- wakeup(rpipe);
- } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) {
- /*
- * Handle write blocking hysteresis.
- */
- if (rpipe->pipe_state & PIPE_WANTW) {
- rpipe->pipe_state &= ~PIPE_WANTW;
- wakeup(rpipe);
- }
- }
-
- if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF)
- pipeselwakeup(rpipe);
-
- PIPE_UNLOCK(rpipe);
- return (error);
-}
-
-#ifndef PIPE_NODIRECT
-/*
- * Map the sending processes' buffer into kernel space and wire it.
- * This is similar to a physical write operation.
- */
-static int
-pipe_build_write_buffer(wpipe, uio)
- struct pipe *wpipe;
- struct uio *uio;
-{
- pmap_t pmap;
- u_int size;
- int i, j;
- vm_offset_t addr, endaddr;
-
- PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED);
- KASSERT(wpipe->pipe_state & PIPE_DIRECTW,
- ("Clone attempt on non-direct write pipe!"));
-
- size = (u_int) uio->uio_iov->iov_len;
- if (size > wpipe->pipe_buffer.size)
- size = wpipe->pipe_buffer.size;
-
- pmap = vmspace_pmap(curproc->p_vmspace);
- endaddr = round_page((vm_offset_t)uio->uio_iov->iov_base + size);
- addr = trunc_page((vm_offset_t)uio->uio_iov->iov_base);
- for (i = 0; addr < endaddr; addr += PAGE_SIZE, i++) {
- /*
- * vm_fault_quick() can sleep. Consequently,
- * vm_page_lock_queue() and vm_page_unlock_queue()
- * should not be performed outside of this loop.
- */
- race:
- if (vm_fault_quick((caddr_t)addr, VM_PROT_READ) < 0) {
- vm_page_lock_queues();
- for (j = 0; j < i; j++)
- vm_page_unhold(wpipe->pipe_map.ms[j]);
- vm_page_unlock_queues();
- return (EFAULT);
- }
- wpipe->pipe_map.ms[i] = pmap_extract_and_hold(pmap, addr,
- VM_PROT_READ);
- if (wpipe->pipe_map.ms[i] == NULL)
- goto race;
- }
-
-/*
- * set up the control block
- */
- wpipe->pipe_map.npages = i;
- wpipe->pipe_map.pos =
- ((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK;
- wpipe->pipe_map.cnt = size;
-
-/*
- * and update the uio data
- */
-
- uio->uio_iov->iov_len -= size;
- uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size;
- if (uio->uio_iov->iov_len == 0)
- uio->uio_iov++;
- uio->uio_resid -= size;
- uio->uio_offset += size;
- return (0);
-}
-
-/*
- * unmap and unwire the process buffer
- */
-static void
-pipe_destroy_write_buffer(wpipe)
- struct pipe *wpipe;
-{
- int i;
-
- PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
- vm_page_lock_queues();
- for (i = 0; i < wpipe->pipe_map.npages; i++) {
- vm_page_unhold(wpipe->pipe_map.ms[i]);
- }
- vm_page_unlock_queues();
- wpipe->pipe_map.npages = 0;
-}
-
-/*
- * In the case of a signal, the writing process might go away. This
- * code copies the data into the circular buffer so that the source
- * pages can be freed without loss of data.
- */
-static void
-pipe_clone_write_buffer(wpipe)
- struct pipe *wpipe;
-{
- struct uio uio;
- struct iovec iov;
- int size;
- int pos;
-
- PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
- size = wpipe->pipe_map.cnt;
- pos = wpipe->pipe_map.pos;
-
- wpipe->pipe_buffer.in = size;
- wpipe->pipe_buffer.out = 0;
- wpipe->pipe_buffer.cnt = size;
- wpipe->pipe_state &= ~PIPE_DIRECTW;
-
- PIPE_UNLOCK(wpipe);
- iov.iov_base = wpipe->pipe_buffer.buffer;
- iov.iov_len = size;
- uio.uio_iov = &iov;
- uio.uio_iovcnt = 1;
- uio.uio_offset = 0;
- uio.uio_resid = size;
- uio.uio_segflg = UIO_SYSSPACE;
- uio.uio_rw = UIO_READ;
- uio.uio_td = curthread;
- uiomove_fromphys(wpipe->pipe_map.ms, pos, size, &uio);
- PIPE_LOCK(wpipe);
- pipe_destroy_write_buffer(wpipe);
-}
-
-/*
- * This implements the pipe buffer write mechanism. Note that only
- * a direct write OR a normal pipe write can be pending at any given time.
- * If there are any characters in the pipe buffer, the direct write will
- * be deferred until the receiving process grabs all of the bytes from
- * the pipe buffer. Then the direct mapping write is set-up.
- */
-static int
-pipe_direct_write(wpipe, uio)
- struct pipe *wpipe;
- struct uio *uio;
-{
- int error;
-
-retry:
- PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
- error = pipelock(wpipe, 1);
- if (wpipe->pipe_state & PIPE_EOF)
- error = EPIPE;
- if (error) {
- pipeunlock(wpipe);
- goto error1;
- }
- while (wpipe->pipe_state & PIPE_DIRECTW) {
- if (wpipe->pipe_state & PIPE_WANTR) {
- wpipe->pipe_state &= ~PIPE_WANTR;
- wakeup(wpipe);
- }
- pipeselwakeup(wpipe);
- wpipe->pipe_state |= PIPE_WANTW;
- pipeunlock(wpipe);
- error = msleep(wpipe, PIPE_MTX(wpipe),
- PRIBIO | PCATCH, "pipdww", 0);
- if (error)
- goto error1;
- else
- goto retry;
- }
- wpipe->pipe_map.cnt = 0; /* transfer not ready yet */
- if (wpipe->pipe_buffer.cnt > 0) {
- if (wpipe->pipe_state & PIPE_WANTR) {
- wpipe->pipe_state &= ~PIPE_WANTR;
- wakeup(wpipe);
- }
- pipeselwakeup(wpipe);
- wpipe->pipe_state |= PIPE_WANTW;
- pipeunlock(wpipe);
- error = msleep(wpipe, PIPE_MTX(wpipe),
- PRIBIO | PCATCH, "pipdwc", 0);
- if (error)
- goto error1;
- else
- goto retry;
- }
-
- wpipe->pipe_state |= PIPE_DIRECTW;
-
- PIPE_UNLOCK(wpipe);
- error = pipe_build_write_buffer(wpipe, uio);
- PIPE_LOCK(wpipe);
- if (error) {
- wpipe->pipe_state &= ~PIPE_DIRECTW;
- pipeunlock(wpipe);
- goto error1;
- }
-
- error = 0;
- while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) {
- if (wpipe->pipe_state & PIPE_EOF) {
- pipe_destroy_write_buffer(wpipe);
- pipeselwakeup(wpipe);
- pipeunlock(wpipe);
- error = EPIPE;
- goto error1;
- }
- if (wpipe->pipe_state & PIPE_WANTR) {
- wpipe->pipe_state &= ~PIPE_WANTR;
- wakeup(wpipe);
- }
- pipeselwakeup(wpipe);
- pipeunlock(wpipe);
- error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH,
- "pipdwt", 0);
- pipelock(wpipe, 0);
- }
-
- if (wpipe->pipe_state & PIPE_EOF)
- error = EPIPE;
- if (wpipe->pipe_state & PIPE_DIRECTW) {
- /*
- * this bit of trickery substitutes a kernel buffer for
- * the process that might be going away.
- */
- pipe_clone_write_buffer(wpipe);
- } else {
- pipe_destroy_write_buffer(wpipe);
- }
- pipeunlock(wpipe);
- return (error);
-
-error1:
- wakeup(wpipe);
- return (error);
+ return generic_pipe_read(fp, uio, active_cred, flags, td);
}
-#endif
int
-pipe_write(fp, uio, active_cred, flags, td)
- struct file *fp;
- struct uio *uio;
- struct ucred *active_cred;
- struct thread *td;
- int flags;
+pipe_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
+ struct thread *td)
{
- int error = 0;
- int desiredsize, orig_resid;
- struct pipe *wpipe, *rpipe;
- rpipe = fp->f_data;
- wpipe = rpipe->pipe_peer;
-
- PIPE_LOCK(rpipe);
- error = pipelock(wpipe, 1);
- if (error) {
- PIPE_UNLOCK(rpipe);
- return (error);
- }
- /*
- * detect loss of pipe read side, issue SIGPIPE if lost.
- */
- if (wpipe->pipe_present != PIPE_ACTIVE ||
- (wpipe->pipe_state & PIPE_EOF)) {
- pipeunlock(wpipe);
- PIPE_UNLOCK(rpipe);
- return (EPIPE);
- }
-#ifdef MAC
- error = mac_pipe_check_write(active_cred, wpipe->pipe_pair);
- if (error) {
- pipeunlock(wpipe);
- PIPE_UNLOCK(rpipe);
- return (error);
- }
-#endif
- ++wpipe->pipe_busy;
-
- /* Choose a larger size if it's advantageous */
- desiredsize = max(SMALL_PIPE_SIZE, wpipe->pipe_buffer.size);
- while (desiredsize < wpipe->pipe_buffer.cnt + uio->uio_resid) {
- if (piperesizeallowed != 1)
- break;
- if (amountpipekva > maxpipekva / 2)
- break;
- if (desiredsize == BIG_PIPE_SIZE)
- break;
- desiredsize = desiredsize * 2;
- }
-
- /* Choose a smaller size if we're in a OOM situation */
- if ((amountpipekva > (3 * maxpipekva) / 4) &&
- (wpipe->pipe_buffer.size > SMALL_PIPE_SIZE) &&
- (wpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) &&
- (piperesizeallowed == 1))
- desiredsize = SMALL_PIPE_SIZE;
-
- /* Resize if the above determined that a new size was necessary */
- if ((desiredsize != wpipe->pipe_buffer.size) &&
>>> TRUNCATED FOR MAIL (1000 lines) <<<
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