Backport of fix from asynchvfs branch for PM-LOG-VFS-PM deadlock that resulted in VFS panics.
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39aa2e6489
commit
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5 changed files with 250 additions and 1 deletions
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@ -18,7 +18,7 @@ LDFLAGS = -i
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OBJ = main.o forkexit.o break.o exec.o time.o timers.o \
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signal.o alloc.o utility.o table.o trace.o getset.o misc.o \
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profile.o
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profile.o asynsend.o kputc.o
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# build local binary
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all build: $(SERVER)
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90
servers/pm/asynsend.c
Normal file
90
servers/pm/asynsend.c
Normal file
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@ -0,0 +1,90 @@
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#include "pm.h"
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#define ASYN_NR 100
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PRIVATE asynmsg_t msgtable[ASYN_NR];
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PRIVATE int first_slot= 0, next_slot= 0;
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PUBLIC int asynsend(dst, mp)
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endpoint_t dst;
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message *mp;
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{
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int r, src_ind, dst_ind;
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unsigned flags;
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/* Update first_slot */
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for (; first_slot < next_slot; first_slot++)
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{
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flags= msgtable[first_slot].flags;
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if ((flags & (AMF_VALID|AMF_DONE)) == (AMF_VALID|AMF_DONE))
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{
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if (msgtable[first_slot].result != OK)
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{
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printf(
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"asynsend: found completed entry %d with error %d\n",
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first_slot,
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msgtable[first_slot].result);
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}
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continue;
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}
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if (flags != AMF_EMPTY)
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break;
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}
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if (first_slot >= next_slot)
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{
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/* Reset first_slot and next_slot */
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next_slot= first_slot= 0;
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}
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if (next_slot >= ASYN_NR)
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{
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/* Tell the kernel to stop processing */
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r= senda(NULL, 0);
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if (r != OK)
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panic(__FILE__, "asynsend: senda failed", r);
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dst_ind= 0;
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for (src_ind= first_slot; src_ind<next_slot; src_ind++)
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{
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flags= msgtable[src_ind].flags;
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if ((flags & (AMF_VALID|AMF_DONE)) ==
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(AMF_VALID|AMF_DONE))
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{
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if (msgtable[src_ind].result != OK)
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{
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printf(
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"asynsend: found completed entry %d with error %d\n",
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src_ind,
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msgtable[src_ind].result);
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}
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continue;
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}
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if (flags == AMF_EMPTY)
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continue;
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#if 0
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printf("asynsend: copying entry %d to %d\n",
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src_ind, dst_ind);
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#endif
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if (src_ind != dst_ind)
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msgtable[dst_ind]= msgtable[src_ind];
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dst_ind++;
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}
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first_slot= 0;
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next_slot= dst_ind;
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if (next_slot >= ASYN_NR)
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panic(__FILE__, "asynsend: msgtable full", NO_NUM);
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}
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msgtable[next_slot].dst= dst;
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msgtable[next_slot].msg= *mp;
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msgtable[next_slot].flags= AMF_VALID; /* Has to be last. The kernel
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* scans this table while we
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* are sleeping.
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*/
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next_slot++;
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/* Tell the kernel to rescan the table */
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return senda(msgtable+first_slot, next_slot-first_slot);
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}
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149
servers/pm/kputc.c
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149
servers/pm/kputc.c
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@ -0,0 +1,149 @@
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/* A server must occasionally print some message. It uses a simple version of
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* printf() found in the system lib that calls kputc() to output characters.
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* Printing is done with a call to the kernel, and not by going through FS.
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*
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* This routine can only be used by servers and device drivers. The kernel
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* must define its own kputc(). Note that the log driver also defines its own
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* kputc() to directly call the TTY instead of going through this library.
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*/
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#include "pm.h"
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#include <string.h>
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#include <minix/com.h>
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#define OVERFLOW_STR "[...]\n"
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#define PRINTPROCS (sizeof(procs)/sizeof(procs[0]))
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static char print_buf[80]; /* output is buffered here */
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int kputc_use_private_grants= 0;
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static int buf_count = 0; /* # characters in the buffer */
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static int buf_offset = 0; /* Start of current line in buffer */
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static int procs[] = OUTPUT_PROCS_ARRAY;
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static cp_grant_id_t printgrants[PRINTPROCS];
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static int procbusy[PRINTPROCS];
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static int do_flush = FALSE;
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static int overflow = FALSE;
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/*===========================================================================*
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* kputc *
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*===========================================================================*/
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void kputc(c)
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int c;
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{
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/* Accumulate another character. If 0 or buffer full, print it. */
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int p;
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message m;
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static int firstprint = 1;
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if (c == 0)
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{
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if (buf_count > buf_offset)
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do_flush= TRUE;
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}
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else if (buf_count >= sizeof(print_buf))
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{
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overflow= TRUE;
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if (buf_count > buf_offset)
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do_flush= TRUE;
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}
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else
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print_buf[buf_count++] = c;
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if (!do_flush || buf_offset != 0)
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return;
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buf_offset= buf_count;
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if (kputc_use_private_grants)
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{
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for (p= 0; p<PRINTPROCS; p++)
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printgrants[p]= GRANT_INVALID;
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firstprint= 0;
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}
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if(firstprint) {
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for(p = 0; procs[p] != NONE; p++) {
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printgrants[p] = GRANT_INVALID;
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}
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firstprint = 0;
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/* First time? Initialize grant table;
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* Grant printing processes read copy access to our
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* print buffer forever. (So buffer can't be on stack!)
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*/
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for(p = 0; procs[p] != NONE; p++) {
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printgrants[p] = cpf_grant_direct(procs[p],
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(vir_bytes) print_buf,
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sizeof(print_buf), CPF_READ);
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}
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}
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do_flush= FALSE;
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for(p = 0; procs[p] != NONE; p++) {
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/* Send the buffer to this output driver. */
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m.DIAG_BUF_COUNT = buf_count;
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if(GRANT_VALID(printgrants[p])) {
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m.m_type = DIAGNOSTICS_S;
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m.DIAG_PRINT_BUF_G = (char *) printgrants[p];
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} else {
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m.m_type = DIAGNOSTICS;
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m.DIAG_PRINT_BUF_G = print_buf;
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}
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if (procs[p] == LOG_PROC_NR)
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{
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procbusy[p]= TRUE;
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(void) asynsend(procs[p], &m);
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}
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else
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{
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sendrec(procs[p], &m);
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}
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}
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}
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PUBLIC void diag_repl()
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{
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endpoint_t driver_e;
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int p;
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driver_e= m_in.m_source;
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/* Find busy flag to clear */
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for(p = 0; procs[p] != NONE; p++)
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{
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if (procs[p] == driver_e)
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break;
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}
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if (procs[p] == NONE)
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{
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/* Message from wrong source */
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return;
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}
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procbusy[p]= FALSE;
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/* Wait for more replies? */
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for(p = 0; procs[p] != NONE; p++)
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{
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if (procbusy[p])
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return;
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}
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if (buf_count > buf_offset)
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{
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memmove(&print_buf[0], &print_buf[buf_offset],
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buf_count-buf_offset);
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}
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buf_count -= buf_offset;
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buf_offset= 0;
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if (overflow)
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{
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if (buf_count + sizeof(OVERFLOW_STR) > sizeof(print_buf))
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buf_count= sizeof(print_buf)-sizeof(OVERFLOW_STR);
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overflow= FALSE;
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do_flush= FALSE;
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printf("%s", OVERFLOW_STR);
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}
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kputc(0);
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}
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@ -124,6 +124,10 @@ PUBLIC int main()
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case GETPUID:
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result= do_getpuid();
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break;
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case DIAG_REPL :
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diag_repl();
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result= SUSPEND;
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break;
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default:
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/* Else, if the system call number is valid, perform the
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* call.
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@ -27,6 +27,9 @@ _PROTOTYPE( void swap_inqueue, (struct mproc *rmp) );
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#endif /* !SWAP */
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_PROTOTYPE(int mem_holes_copy, (struct hole *, size_t *, u32_t *) );
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/* asynsend.c */
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_PROTOTYPE( int asynsend, (endpoint_t dst, message *mp) );
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/* break.c */
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_PROTOTYPE( int adjust, (struct mproc *rmp,
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vir_clicks data_clicks, vir_bytes sp) );
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@ -63,6 +66,9 @@ _PROTOTYPE( void real_cleanup, (struct mproc *rmp) );
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/* getset.c */
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_PROTOTYPE( int do_getset, (void) );
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/* kputc.c */
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_PROTOTYPE( void diag_repl, (void) );
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/* main.c */
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_PROTOTYPE( int main, (void) );
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