irq.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <stdbool.h>
   5 #include <errno.h>
   6 #include <sys/types.h>
   7 #include <sys/stat.h>
   8 #include <fcntl.h>
   9
  10 #include "irq.h"
  11 #include "str.h"
  12 #include "die.h"
  13
  14 int device_irq_number(const char *ifname)
  15 {
  16         int irq = 0;
  17         char buff[128], sysname[128];
  18         FILE *fp;
  19
  20         if (!strncmp("lo", ifname, strlen("lo")))
  21                 return 0;
  22
  23         slprintf(sysname, sizeof(sysname),
  24                  "/sys/class/net/%s/device/irq",
  25                  ifname);
  26
  27         fp = fopen(sysname, "r");
  28         if (!fp)
  29                 return -ENOENT;
  30
  31         memset(buff, 0, sizeof(buff));
  32
  33         if (fgets(buff, sizeof(buff), fp) != NULL) {
  34                 buff[sizeof(buff) - 1] = 0;
  35                 irq = atoi(buff);
  36         }
  37
  38         fclose(fp);
  39         return irq;
  40 }
  41
  42 static char nic_irq_affinity_list[128];
  43 static bool nic_irq_stored = false;
  44 static int  nic_irq = -1;
  45
  46 static void device_save_irq_affinity_list(void)
  47 {
  48         int ret, fd;
  49         char file[128];
  50
  51         bug_on(nic_irq_stored);
  52
  53         slprintf(file, sizeof(file),
  54                  "/proc/irq/%d/smp_affinity_list", nic_irq);
  55
  56         fd = open(file, O_RDONLY);
  57         if (fd < 0)
  58                 return;
  59
  60         memset(nic_irq_affinity_list, 0, sizeof(nic_irq_affinity_list));
  61
  62         ret = read(fd, nic_irq_affinity_list,
  63                    sizeof(nic_irq_affinity_list));
  64         if (ret < 0)
  65                 panic("Cannot store NIC IRQ affinity!\n");
  66
  67         close(fd);
  68
  69         nic_irq_stored = true;
  70 }
  71
  72 void device_restore_irq_affinity_list(void)
  73 {
  74         int ret, fd;
  75         char file[128];
  76
  77         if (!nic_irq_stored)
  78                 return;
  79
  80         bug_on(nic_irq == -1);
  81
  82         slprintf(file, sizeof(file),
  83                  "/proc/irq/%d/smp_affinity_list", nic_irq);
  84
  85         fd = open(file, O_WRONLY);
  86         if (fd < 0)
  87                 return;
  88
  89         ret = write(fd, nic_irq_affinity_list,
  90                     sizeof(nic_irq_affinity_list));
  91         if (ret < 0)
  92                 panic("Cannot restore NIC IRQ affinity!\n");
  93
  94         close(fd);
  95 }
  96
  97 int device_set_irq_affinity_list(int irq, unsigned long from, unsigned long to)
  98 {
  99         int ret, fd;
 100         char file[128], list[64];
 101
 102         if (unlikely(irq == 0))
 103                 return 0;
 104         if (!nic_irq_stored) {
 105                 nic_irq = irq;
 106                 device_save_irq_affinity_list();
 107         }
 108
 109         slprintf(file, sizeof(file), "/proc/irq/%d/smp_affinity_list", irq);
 110         slprintf(list, sizeof(list), "%lu-%lu\n", from, to);
 111
 112         fd = open(file, O_WRONLY);
 113         if (fd < 0)
 114                 return -ENOENT;
 115
 116         ret = write(fd, list, strlen(list));
 117
 118         close(fd);
 119         return ret;
 120 }
 121
 122 int device_set_irq_affinity(int irq, unsigned long cpu)
 123 {
 124         return device_set_irq_affinity_list(irq, cpu, cpu);
 125 }