From 7bbe4907c662b95a9d4d02d9abeec7d176e04f33 Mon Sep 17 00:00:00 2001
From: Peng Tao <bergwolf@gmail.com>
Date: Tue, 15 Oct 2013 15:43:55 +0800
Subject: [PATCH] staging/lustre/obdclass: read jobid from proc
so that we can get rid of cfs_get_environ() that needs access_process_vm() that
is a core mm function and is not available on some architectures.
Signed-off-by: Peng Tao <bergwolf@gmail.com>
---
.../lustre/lustre/obdclass/class_obd.c | 96 ++++++++++++++++++-
1 file changed, 95 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/lustre/lustre/obdclass/class_obd.c b/drivers/staging/lustre/lustre/obdclass/class_obd.c
index b1024a6d37dd95..0186ebba96d3fe 100644
--- a/drivers/staging/lustre/lustre/obdclass/class_obd.c
+++ b/drivers/staging/lustre/lustre/obdclass/class_obd.c
@@ -96,6 +96,98 @@ EXPORT_SYMBOL(obd_dirty_transit_pages);
char obd_jobid_var[JOBSTATS_JOBID_VAR_MAX_LEN + 1] = JOBSTATS_DISABLE;
EXPORT_SYMBOL(obd_jobid_var);
+static char *self_environ_file = "/proc/self/environ";
+static int obd_get_environ(const char *key, char *value, int *val_len)
+{
+ struct path path;
+ struct file *filp = NULL;
+ int buf_len = PAGE_CACHE_SIZE;
+ int key_len = strlen(key);
+ char *buffer = NULL;
+ loff_t pos = 0;
+ int rc;
+
+ buffer = kmalloc(buf_len, GFP_USER);
+ if (!buffer)
+ return -ENOMEM;
+
+ rc = kern_path(self_environ_file, LOOKUP_FOLLOW, &path);
+ if (rc)
+ goto out;
+
+ filp = dentry_open(&path, O_RDONLY, current_cred());
+ if (IS_ERR(filp)) {
+ rc = PTR_ERR(filp);
+ filp = NULL;
+ goto out;
+ }
+
+ /* loop reading... */
+ while (1) {
+ int scan_len, this_len;
+ char *env_start, *env_end;
+ rc = kernel_read(filp, pos, buffer, buf_len);
+ if (rc <= 0)
+ break;
+
+ pos += rc;
+ /* Parse the buffer to find out the specified key/value pair.
+ * The "key=value" entries are separated by '\0'. */
+ env_start = buffer;
+ scan_len = this_len = rc;
+ while (scan_len) {
+ char *entry;
+ int entry_len;
+
+ env_end = memscan(env_start, '\0', scan_len);
+ LASSERT(env_end >= env_start &&
+ env_end <= env_start + scan_len);
+
+ /* The last entry of this buffer cross the buffer
+ * boundary, reread it in next cycle. */
+ if (unlikely(env_end - env_start == scan_len)) {
+ /* This entry is too large to fit in buffer */
+ if (unlikely(scan_len == this_len)) {
+ CERROR("Too long env variable.\n");
+ rc = -EINVAL;
+ goto out;
+ }
+ pos -= scan_len;
+ break;
+ }
+
+ entry = env_start;
+ entry_len = env_end - env_start;
+
+ /* Key length + length of '=' */
+ if (entry_len > key_len + 1 &&
+ !memcmp(entry, key, key_len)) {
+ entry += key_len + 1;
+ entry_len -= key_len + 1;
+ /* The 'value' buffer passed in is too small.*/
+ if (entry_len >= *val_len)
+ GOTO(out, rc = -EOVERFLOW);
+
+ memcpy(value, entry, entry_len);
+ *val_len = entry_len;
+ rc = 0;
+ goto out;
+ }
+
+ scan_len -= (env_end - env_start + 1);
+ env_start = env_end + 1;
+ }
+ }
+ if (rc >= 0)
+ rc = -ENOENT;
+out:
+ if (filp)
+ fput(filp);
+ if (buffer)
+ kfree(buffer);
+ return rc;
+}
+
/* Get jobid of current process by reading the environment variable
* stored in between the "env_start" & "env_end" of task struct.
*
@@ -126,7 +218,7 @@ int lustre_get_jobid(char *jobid)
return 0;
}
- rc = cfs_get_environ(obd_jobid_var, jobid, &jobid_len);
+ rc = obd_get_environ(obd_jobid_var, jobid, &jobid_len);
if (rc) {
if (rc == -EOVERFLOW) {
/* For the PBS_JOBID and LOADL_STEP_ID keys (which are
@@ -149,6 +241,8 @@ int lustre_get_jobid(char *jobid)
"Get jobid for (%s) failed: rc = %d\n",
obd_jobid_var, rc);
}
+ } else {
+ CDEBUG(D_INFO, "Got jobid for (%s) value (%s)\n", obd_jobid_var, jobid);
}
return rc;
}