Apply fix from bug239 for rwlock deadlock.

Update check.sh script to take V=1 env var so you can run it verbosely as
follows if your chasing something: sudo make check V=1

Add new kobj api and needed regression tests to allow reading of files from
within the kernel.  Normally thats not something I support but the spa layer
needs the support for its config file.

Add some more missing stub headers



git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@38 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c

include/sys/cred.h

@@ -6,7 +6,7 @@ extern "C" {
 #endif
 
 #include <linux/module.h>
-#include <linux/types.h>
+#include <sys/types.h>
 
 /* XXX - Portions commented out because we really just want to have the type
  * defined and the contents aren't nearly so important at the moment. */

include/sys/kidmap.h

@@ -0,0 +1,4 @@
+#ifndef _SPL_KIDMAP_H
+#define _SPL_KIDMAP_H
+
+#endif /* SPL_KIDMAP_H */

include/sys/kobj.h

@@ -0,0 +1,29 @@
+#ifndef _SPL_KOBJ_H
+#define _SPL_KOBJ_H
+
+#ifdef  __cplusplus
+extern "C" {
+#endif
+
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <sys/types.h>
+#include <sys/kmem.h>
+
+typedef struct _buf {
+	struct file *fp;
+} _buf_t;
+
+extern void *rootdir;
+
+extern struct _buf *kobj_open_file(const char *name);
+extern void kobj_close_file(struct _buf *file);
+extern int kobj_read_file(struct _buf *file, char *buf,
+			  unsigned size, unsigned off);
+extern int kobj_get_filesize(struct _buf *file, uint64_t *size);
+
+#ifdef  __cplusplus
+}
+#endif
+
+#endif /* SPL_KOBJ_H */

include/sys/rwlock.h

@@ -36,6 +36,65 @@ typedef struct {
 	struct task_struct *rw_owner;	/* holder of the write lock */
 } krwlock_t;
 
+#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
+struct rwsem_waiter {
+	struct list_head list;
+	struct task_struct *task;
+	unsigned int flags;
+#define RWSEM_WAITING_FOR_READ	0x00000001
+#define RWSEM_WAITING_FOR_WRITE	0x00000002
+};
+
+/*
+ * wake a single writer
+ */
+static inline struct rw_semaphore *
+__rwsem_wake_one_writer_locked(struct rw_semaphore *sem)
+{
+	struct rwsem_waiter *waiter;
+	struct task_struct *tsk;
+
+	sem->activity = -1;
+
+	waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
+	list_del(&waiter->list);
+
+	tsk = waiter->task;
+	smp_mb();
+	waiter->task = NULL;
+	wake_up_process(tsk);
+	put_task_struct(tsk);
+	return sem;
+}
+
+/*
+ * release a read lock on the semaphore
+ */
+static void fastcall
+__up_read_locked(struct rw_semaphore *sem)
+{
+	if (--sem->activity == 0 && !list_empty(&sem->wait_list))
+		sem = __rwsem_wake_one_writer_locked(sem);
+}
+
+/*
+ * trylock for writing -- returns 1 if successful, 0 if contention
+ */
+static int fastcall
+__down_write_trylock_locked(struct rw_semaphore *sem)
+{
+	int ret = 0;
+
+	if (sem->activity == 0 && list_empty(&sem->wait_list)) {
+		/* granted */
+		sem->activity = -1;
+		ret = 1;
+	}
+
+	return ret;
+}
+#endif
+
 extern int __rw_read_held(krwlock_t *rwlp);
 extern int __rw_write_held(krwlock_t *rwlp);
 extern int __rw_lock_held(krwlock_t *rwlp);
@@ -168,7 +227,7 @@ rw_downgrade(krwlock_t *rwlp)
 static __inline__ int
 rw_tryupgrade(krwlock_t *rwlp)
 {
-	int result;
+	int result = 0;
 	BUG_ON(rwlp->rw_magic != RW_MAGIC);
 
 	spin_lock(&rwlp->rw_sem.wait_lock);
@@ -197,6 +256,15 @@ rw_tryupgrade(krwlock_t *rwlp)
 		return 0;
 	}
 
+#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
+	/* Here it should be safe to drop the
+	 * read lock and reacquire it for writing since
+	 * we know there are no waiters */
+	__up_read_locked(&rwlp->rw_sem);
+
+	/* returns 1 if success, 0 if contention */
+	result = __down_write_trylock_locked(&rwlp->rw_sem);
+#else
 	/* Here it should be safe to drop the
 	 * read lock and reacquire it for writing since
 	 * we know there are no waiters */
@@ -204,6 +272,7 @@ rw_tryupgrade(krwlock_t *rwlp)
 
 	/* returns 1 if success, 0 if contention */
 	result = down_write_trylock(&rwlp->rw_sem);
+#endif
 
 	/* Check if upgrade failed.  Should not ever happen
 	 * if we got to this point */

include/sys/sid.h

@@ -0,0 +1,4 @@
+#ifndef _SPL_SID_H
+#define _SPL_SID_H
+
+#endif /* SPL_SID_H */

include/sys/sysmacros.h

@@ -135,7 +135,6 @@ extern int highbit(unsigned long i);
 #define makedevice(maj,min) makedev(maj,min)
 #define zone_dataset_visible(x, y)			(1)
 #define INGLOBALZONE(z)					(1)
-#define utsname						system_utsname
 
 /* XXX - Borrowed from zfs project libsolcompat/include/sys/sysmacros.h */
 /* common macros */

include/sys/utsname.h

@@ -0,0 +1,8 @@
+#ifndef _SPL_UTSNAME_H
+#define _SPL_UTSNAME_H
+
+#include <linux/utsname.h>
+
+#define utsname				system_utsname
+
+#endif /* SPL_UTSNAME_H */

include/sys/vfs.h

@@ -1,4 +1,8 @@
 #ifndef _SPL_ZFS_H
 #define _SPL_ZFS_H
 
+typedef struct vfs_s {
+	int foo;
+} vfs_t;
+
 #endif /* SPL_ZFS_H */

modules/spl/Makefile.in

@@ -16,6 +16,7 @@ spl-objs += spl-rwlock.o
 spl-objs += spl-vnode.o
 spl-objs += spl-err.o
 spl-objs += spl-time.o
+spl-objs += spl-kobj.o
 spl-objs += spl-generic.o
 
 splmodule := spl.ko

modules/spl/spl-kobj.c

@@ -0,0 +1,75 @@
+#include <sys/kobj.h>
+#include "config.h"
+
+void *rootdir = NULL;
+EXPORT_SYMBOL(rootdir);
+
+struct _buf *
+kobj_open_file(const char *name)
+{
+	struct _buf *file;
+	struct file *fp;
+
+	fp = filp_open(name, O_RDONLY, 0644);
+	if (IS_ERR(fp))
+		return ((_buf_t *)-1UL);
+
+	file = kmem_zalloc(sizeof(_buf_t), KM_SLEEP);
+	file->fp = fp;
+
+	return file;
+} /* kobj_open_file() */
+EXPORT_SYMBOL(kobj_open_file);
+
+void
+kobj_close_file(struct _buf *file)
+{
+        filp_close(file->fp, 0);
+        kmem_free(file, sizeof(_buf_t));
+
+	return;
+} /* kobj_close_file() */
+EXPORT_SYMBOL(kobj_close_file);
+
+int
+kobj_read_file(struct _buf *file, char *buf, unsigned size, unsigned off)
+{
+	loff_t offset = off;
+	mm_segment_t saved_fs;
+	int rc;
+
+	if (!file || !file->fp)
+		return -EINVAL;
+
+	if (!file->fp->f_op || !file->fp->f_op->read)
+		return -ENOSYS;
+
+	/* Writable user data segment must be briefly increased for this
+	 * process so we can use the user space read call paths to write
+	 * in to memory allocated by the kernel. */
+	saved_fs = get_fs();
+        set_fs(get_ds());
+	rc = file->fp->f_op->read(file->fp, buf, size, &offset);
+	set_fs(saved_fs);
+
+	return rc;
+} /* kobj_read_file() */
+EXPORT_SYMBOL(kobj_read_file);
+
+int
+kobj_get_filesize(struct _buf *file, uint64_t *size)
+{
+        struct kstat stat;
+	int rc;
+
+	if (!file || !file->fp || !size)
+		return -EINVAL;
+
+        rc = vfs_getattr(file->fp->f_vfsmnt, file->fp->f_dentry, &stat);
+	if (rc)
+		return rc;
+
+        *size = stat.size;
+        return rc;
+} /* kobj_get_filesize() */
+EXPORT_SYMBOL(kobj_get_filesize);

modules/splat/Makefile.in

@@ -21,6 +21,7 @@ splat-objs += splat-condvar.o
 splat-objs += splat-thread.o
 splat-objs += splat-rwlock.o
 splat-objs += splat-time.o
+splat-objs += splat-kobj.o
 
 splatmodule := splat.ko
 splatmoduledir := @kmoduledir@/kernel/lib/

modules/splat/splat-ctl.c

@@ -591,6 +591,7 @@ splat_init(void)
 	SPLAT_SUBSYSTEM_INIT(thread);
 	SPLAT_SUBSYSTEM_INIT(rwlock);
 	SPLAT_SUBSYSTEM_INIT(time);
+	SPLAT_SUBSYSTEM_INIT(kobj);
 
 	dev = MKDEV(SPLAT_MAJOR, 0);
         if ((rc = register_chrdev_region(dev, SPLAT_MINORS, "splatctl")))
@@ -652,6 +653,7 @@ splat_fini(void)
         cdev_del(&splat_cdev);
         unregister_chrdev_region(dev, SPLAT_MINORS);
 
+	SPLAT_SUBSYSTEM_FINI(kobj);
 	SPLAT_SUBSYSTEM_FINI(time);
 	SPLAT_SUBSYSTEM_FINI(rwlock);
 	SPLAT_SUBSYSTEM_FINI(thread);

modules/splat/splat-internal.h

@@ -32,6 +32,7 @@
 #include <sys/time.h>
 #include <sys/timer.h>
 #include <sys/types.h>
+#include <sys/kobj.h>
 
 #include "splat-ctl.h"
 
@@ -169,6 +170,7 @@ splat_subsystem_t * splat_rwlock_init(void);
 splat_subsystem_t * splat_taskq_init(void);
 splat_subsystem_t * splat_thread_init(void);
 splat_subsystem_t * splat_time_init(void);
+splat_subsystem_t * splat_kobj_init(void);
 
 void splat_condvar_fini(splat_subsystem_t *);
 void splat_kmem_fini(splat_subsystem_t *);
@@ -178,6 +180,7 @@ void splat_rwlock_fini(splat_subsystem_t *);
 void splat_taskq_fini(splat_subsystem_t *);
 void splat_thread_fini(splat_subsystem_t *);
 void splat_time_fini(splat_subsystem_t *);
+void splat_kobj_fini(splat_subsystem_t *);
 
 int splat_condvar_id(void);
 int splat_kmem_id(void);
@@ -187,5 +190,6 @@ int splat_rwlock_id(void);
 int splat_taskq_id(void);
 int splat_thread_id(void);
 int splat_time_id(void);
+int splat_kobj_id(void);
 
 #endif /* _SPLAT_INTERNAL_H */

modules/splat/splat-kobj.c

@@ -0,0 +1,137 @@
+#include "splat-internal.h"
+
+#define SPLAT_SUBSYSTEM_KOBJ		0x0900
+#define SPLAT_KOBJ_NAME			"kobj"
+#define SPLAT_KOBJ_DESC			"Kernel File Tests"
+
+#define SPLAT_KOBJ_TEST1_ID		0x0901
+#define SPLAT_KOBJ_TEST1_NAME		"kobj1"
+#define SPLAT_KOBJ_TEST1_DESC		"File Open/Close Test"
+
+#define SPLAT_KOBJ_TEST2_ID		0x0902
+#define SPLAT_KOBJ_TEST2_NAME		"kobj2"
+#define SPLAT_KOBJ_TEST2_DESC		"File Size/Read Test"
+
+#define SPLAT_KOBJ_TEST_FILE		"/etc/fstab"
+
+static int
+splat_kobj_test1(struct file *file, void *arg)
+{
+	struct _buf *f;
+
+	f = kobj_open_file(SPLAT_KOBJ_TEST_FILE);
+	if (f == (struct _buf *)-1) {
+		splat_vprint(file, SPLAT_KOBJ_TEST1_NAME, "Failed to open "
+			     "test file: %s\n", SPLAT_KOBJ_TEST_FILE);
+		return -ENOENT;
+	}
+
+	kobj_close_file(f);
+	splat_vprint(file, SPLAT_KOBJ_TEST1_NAME, "Successfully opened and "
+		     "closed test file: %s\n", SPLAT_KOBJ_TEST_FILE);
+
+        return 0;
+} /* splat_kobj_test1() */
+
+static int
+splat_kobj_test2(struct file *file, void *arg)
+{
+	struct _buf *f;
+	char *buf;
+	uint64_t size;
+	int rc;
+
+	f = kobj_open_file(SPLAT_KOBJ_TEST_FILE);
+	if (f == (struct _buf *)-1) {
+		splat_vprint(file, SPLAT_KOBJ_TEST2_NAME, "Failed to open "
+			     "test file: %s\n", SPLAT_KOBJ_TEST_FILE);
+		return -ENOENT;
+	}
+
+	rc = kobj_get_filesize(f, &size);
+	if (rc) {
+		splat_vprint(file, SPLAT_KOBJ_TEST2_NAME, "Failed stat of "
+			     "test file: %s (%d)\n", SPLAT_KOBJ_TEST_FILE, rc);
+		goto out;
+	}
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf) {
+		rc = -ENOMEM;
+		splat_vprint(file, SPLAT_KOBJ_TEST2_NAME, "Failed to alloc "
+			     "%lld bytes for tmp buffer (%d)\n", size, rc);
+		goto out;
+	}
+
+	rc = kobj_read_file(f, buf, size, 0);
+	if (rc < 0) {
+		splat_vprint(file, SPLAT_KOBJ_TEST2_NAME, "Failed read of "
+			     "test file: %s (%d)\n", SPLAT_KOBJ_TEST_FILE, rc);
+		goto out2;
+	}
+
+	/* Validate we read as many bytes as expected based on the stat.  This
+	 * isn't a perfect test since we didn't create the file however it is
+	 * pretty unlikely there are garbage characters in your /etc/fstab */
+	if (size != (uint64_t)strlen(buf)) {
+		rc = EFBIG;
+		splat_vprint(file, SPLAT_KOBJ_TEST2_NAME, "Stat'ed size "
+			     "(%lld) does not match number of bytes read "
+			     "(%lld)\n", size, (uint64_t)strlen(buf));
+		goto out2;
+	}
+
+	rc = 0;
+	splat_vprint(file, SPLAT_KOBJ_TEST2_NAME, "\n%s\n", buf);
+	splat_vprint(file, SPLAT_KOBJ_TEST2_NAME, "Successfully stat'ed "
+		     "and read expected number of bytes (%lld) from test "
+		     "file: %s\n", size, SPLAT_KOBJ_TEST_FILE);
+out2:
+	kfree(buf);
+out:
+	kobj_close_file(f);
+
+        return rc;
+} /* splat_kobj_test2() */
+
+splat_subsystem_t *
+splat_kobj_init(void)
+{
+        splat_subsystem_t *sub;
+
+        sub = kmalloc(sizeof(*sub), GFP_KERNEL);
+        if (sub == NULL)
+                return NULL;
+
+        memset(sub, 0, sizeof(*sub));
+        strncpy(sub->desc.name, SPLAT_KOBJ_NAME, SPLAT_NAME_SIZE);
+	strncpy(sub->desc.desc, SPLAT_KOBJ_DESC, SPLAT_DESC_SIZE);
+        INIT_LIST_HEAD(&sub->subsystem_list);
+	INIT_LIST_HEAD(&sub->test_list);
+        spin_lock_init(&sub->test_lock);
+        sub->desc.id = SPLAT_SUBSYSTEM_KOBJ;
+
+        SPLAT_TEST_INIT(sub, SPLAT_KOBJ_TEST1_NAME, SPLAT_KOBJ_TEST1_DESC,
+	              SPLAT_KOBJ_TEST1_ID, splat_kobj_test1);
+        SPLAT_TEST_INIT(sub, SPLAT_KOBJ_TEST2_NAME, SPLAT_KOBJ_TEST2_DESC,
+	              SPLAT_KOBJ_TEST2_ID, splat_kobj_test2);
+
+        return sub;
+} /* splat_kobj_init() */
+
+void
+splat_kobj_fini(splat_subsystem_t *sub)
+{
+        ASSERT(sub);
+
+        SPLAT_TEST_FINI(sub, SPLAT_KOBJ_TEST2_ID);
+        SPLAT_TEST_FINI(sub, SPLAT_KOBJ_TEST1_ID);
+
+        kfree(sub);
+} /* splat_kobj_fini() */
+
+int
+splat_kobj_id(void)
+{
+        return SPLAT_SUBSYSTEM_KOBJ;
+} /* splat_kobj_id() */

scripts/check.sh

@@ -4,6 +4,7 @@ prog=check.sh
 spl_module=../modules/spl/spl.ko
 splat_module=../modules/splat/splat.ko
 splat_cmd=../cmd/splat
+verbose=
 
 die() {
 	echo "${prog}: $1" >&2
@@ -14,6 +15,10 @@ warn() {
 	echo "${prog}: $1" >&2
 }
 
+if [ -n "$V" ]; then
+	verbose="-v"
+fi
+
 if [ $(id -u) != 0 ]; then
 	die "Must run as root"
 fi
@@ -32,8 +37,8 @@ echo "Loading ${spl_module}"
 echo "Loading ${splat_module}"
 /sbin/insmod ${splat_module} || die "Unable to load ${splat_module}"
 
-sleep 5
+sleep 3
-$splat_cmd -a
+$splat_cmd -a $verbose
 
 echo "Unloading ${splat_module}"
 /sbin/rmmod ${splat_module} || die "Failed to unload ${splat_module}"