diff options
Diffstat (limited to 'libpager/data-request.c')
| -rw-r--r-- | libpager/data-request.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/libpager/data-request.c b/libpager/data-request.c new file mode 100644 index 00000000..0c6d1625 --- /dev/null +++ b/libpager/data-request.c @@ -0,0 +1,152 @@ +/* Implementation of memory_object_data_request for pager library + Copyright (C) 1994, 1995, 1996, 1997 Free Software Foundation + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + This program is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include "priv.h" +#include "memory_object_S.h" +#include <stdio.h> +#include <string.h> + +/* Implement pagein callback as described in <mach/memory_object.defs>. */ +kern_return_t +_pager_seqnos_memory_object_data_request (mach_port_t object, + mach_port_seqno_t seqno, + mach_port_t control, + vm_offset_t offset, + vm_size_t length, + vm_prot_t access) +{ + struct pager *p; + char *pm_entry; + int doread, doerror; + error_t err; + vm_address_t page; + int write_lock; + + p = ports_lookup_port (0, object, _pager_class); + if (!p) + return EOPNOTSUPP; + + /* Acquire the right to meddle with the pagemap */ + mutex_lock (&p->interlock); + _pager_wait_for_seqno (p, seqno); + + /* sanity checks -- we don't do multi-page requests yet. */ + if (control != p->memobjcntl) + { + printf ("incg data request: wrong control port\n"); + goto release_out; + } + if (length != __vm_page_size) + { + printf ("incg data request: bad length size %d\n", length); + goto release_out; + } + if (offset % __vm_page_size) + { + printf ("incg data request: misaligned request\n"); + goto release_out; + } + + _pager_block_termination (p); /* prevent termination until + mark_object_error is done */ + + if (p->pager_state != NORMAL) + { + printf ("pager in wrong state for read\n"); + _pager_release_seqno (p, seqno); + mutex_unlock (&p->interlock); + goto allow_term_out; + } + + err = _pager_pagemap_resize (p, offset + length); + if (err) + goto release_out; /* Can't do much about the actual error. */ + + /* If someone is paging this out right now, the disk contents are + unreliable, so we have to wait. It is too expensive (right now) to + find the data and return it, and then interrupt the write, so we just + mark the page and have the writing thread do m_o_data_supply when it + gets around to it. */ + pm_entry = &p->pagemap[offset / __vm_page_size]; + if (*pm_entry & PM_PAGINGOUT) + { + doread = 0; + *pm_entry |= PM_PAGEINWAIT; + } + else + doread = 1; + + if (*pm_entry & PM_INVALID) + doerror = 1; + else + doerror = 0; + + *pm_entry |= PM_INCORE; + + if (PM_NEXTERROR (*pm_entry) != PAGE_NOERR && (access & VM_PROT_WRITE)) + { + memory_object_data_error (control, offset, length, + _pager_page_errors[PM_NEXTERROR (*pm_entry)]); + _pager_mark_object_error (p, offset, length, + _pager_page_errors[PM_NEXTERROR (*pm_entry)]); + *pm_entry = SET_PM_NEXTERROR (*pm_entry, PAGE_NOERR); + doread = 0; + } + + /* Let someone else in. */ + _pager_release_seqno (p, seqno); + mutex_unlock (&p->interlock); + + if (!doread) + goto allow_term_out; + if (doerror) + goto error_read; + + err = pager_read_page (p->upi, offset, &page, &write_lock); + if (err) + goto error_read; + + memory_object_data_supply (p->memobjcntl, offset, page, length, 1, + write_lock ? VM_PROT_WRITE : VM_PROT_NONE, 0, + MACH_PORT_NULL); + mutex_lock (&p->interlock); + _pager_mark_object_error (p, offset, length, 0); + _pager_allow_termination (p); + mutex_unlock (&p->interlock); + ports_port_deref (p); + return 0; + + allow_term_out: + mutex_lock (&p->interlock); + _pager_allow_termination (p); + mutex_unlock (&p->interlock); + ports_port_deref (p); + return 0; + + error_read: + memory_object_data_error (p->memobjcntl, offset, length, EIO); + _pager_mark_object_error (p, offset, length, EIO); + _pager_allow_termination (p); + ports_port_deref (p); + return 0; + + release_out: + _pager_release_seqno (p, seqno); + mutex_unlock (&p->interlock); + ports_port_deref (p); + return 0; +} |