new helpers: no_seek_end_llseek{,_size}()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

13 files changed, 54 insertions, 222 deletions

diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c
index 6f80936e0eea..11228861d9b4 100644
--- a/arch/sparc/kernel/mdesc.c
+++ b/arch/sparc/kernel/mdesc.c
@@ -1033,25 +1033,9 @@ static ssize_t mdesc_read(struct file *file, char __user *buf,
 
 static loff_t mdesc_llseek(struct file *file, loff_t offset, int whence)
 {
-	struct mdesc_handle *hp;
-
-	switch (whence) {
-	case SEEK_CUR:
-		offset += file->f_pos;
-		break;
-	case SEEK_SET:
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	hp = file->private_data;
-	if (offset > hp->handle_size)
-		return -EINVAL;
-	else
-		file->f_pos = offset;
+	struct mdesc_handle *hp = file->private_data;
 
-	return offset;
+	return no_seek_end_llseek_size(file, offset, whence, hp->handle_size);
 }
 
 /* mdesc_close() - /dev/mdesc is being closed, release the reference to
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index bd3507da39f0..2836de390f95 100644
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -58,28 +58,6 @@ static void cpuid_smp_cpuid(void *cmd_block)
 		    &cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx);
 }
 
-static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
-{
-	loff_t ret;
-	struct inode *inode = file->f_mapping->host;
-
-	mutex_lock(&inode->i_mutex);
-	switch (orig) {
-	case 0:
-		file->f_pos = offset;
-		ret = file->f_pos;
-		break;
-	case 1:
-		file->f_pos += offset;
-		ret = file->f_pos;
-		break;
-	default:
-		ret = -EINVAL;
-	}
-	mutex_unlock(&inode->i_mutex);
-	return ret;
-}
-
 static ssize_t cpuid_read(struct file *file, char __user *buf,
 			  size_t count, loff_t *ppos)
 {
@@ -132,7 +110,7 @@ static int cpuid_open(struct inode *inode, struct file *file)
  */
 static const struct file_operations cpuid_fops = {
 	.owner = THIS_MODULE,
-	.llseek = cpuid_seek,
+	.llseek = no_seek_end_llseek,
 	.read = cpuid_read,
 	.open = cpuid_open,
 };
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 113e70784854..64f9616f93f1 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -45,28 +45,6 @@
 
 static struct class *msr_class;
 
-static loff_t msr_seek(struct file *file, loff_t offset, int orig)
-{
-	loff_t ret;
-	struct inode *inode = file_inode(file);
-
-	mutex_lock(&inode->i_mutex);
-	switch (orig) {
-	case SEEK_SET:
-		file->f_pos = offset;
-		ret = file->f_pos;
-		break;
-	case SEEK_CUR:
-		file->f_pos += offset;
-		ret = file->f_pos;
-		break;
-	default:
-		ret = -EINVAL;
-	}
-	mutex_unlock(&inode->i_mutex);
-	return ret;
-}
-
 static ssize_t msr_read(struct file *file, char __user *buf,
 			size_t count, loff_t *ppos)
 {
@@ -194,7 +172,7 @@ static int msr_open(struct inode *inode, struct file *file)
  */
 static const struct file_operations msr_fops = {
 	.owner = THIS_MODULE,
-	.llseek = msr_seek,
+	.llseek = no_seek_end_llseek,
 	.read = msr_read,
 	.write = msr_write,
 	.open = msr_open,
diff --git a/drivers/char/nwflash.c b/drivers/char/nwflash.c
index e371480d3639..dbe598de9b74 100644
--- a/drivers/char/nwflash.c
+++ b/drivers/char/nwflash.c
@@ -277,36 +277,7 @@ static loff_t flash_llseek(struct file *file, loff_t offset, int orig)
 		printk(KERN_DEBUG "flash_llseek: offset=0x%X, orig=0x%X.\n",
 		       (unsigned int) offset, orig);
 
-	switch (orig) {
-	case 0:
-		if (offset < 0) {
-			ret = -EINVAL;
-			break;
-		}
-
-		if ((unsigned int) offset > gbFlashSize) {
-			ret = -EINVAL;
-			break;
-		}
-
-		file->f_pos = (unsigned int) offset;
-		ret = file->f_pos;
-		break;
-	case 1:
-		if ((file->f_pos + offset) > gbFlashSize) {
-			ret = -EINVAL;
-			break;
-		}
-		if ((file->f_pos + offset) < 0) {
-			ret = -EINVAL;
-			break;
-		}
-		file->f_pos += offset;
-		ret = file->f_pos;
-		break;
-	default:
-		ret = -EINVAL;
-	}
+	ret = no_seek_end_llseek_size(file, offset, orig, gbFlashSize);
 	mutex_unlock(&flash_mutex);
 	return ret;
 }
diff --git a/drivers/net/wireless/ti/wlcore/debugfs.c b/drivers/net/wireless/ti/wlcore/debugfs.c
index eb43f94a1597..be72306f8c69 100644
--- a/drivers/net/wireless/ti/wlcore/debugfs.c
+++ b/drivers/net/wireless/ti/wlcore/debugfs.c
@@ -1205,26 +1205,11 @@ err_out:
 
 static loff_t dev_mem_seek(struct file *file, loff_t offset, int orig)
 {
-	loff_t ret;
-
 	/* only requests of dword-aligned size and offset are supported */
 	if (offset % 4)
 		return -EINVAL;
 
-	switch (orig) {
-	case SEEK_SET:
-		file->f_pos = offset;
-		ret = file->f_pos;
-		break;
-	case SEEK_CUR:
-		file->f_pos += offset;
-		ret = file->f_pos;
-		break;
-	default:
-		ret = -EINVAL;
-	}
-
-	return ret;
+	return no_seek_end_llseek(file, offset, orig);
 }
 
 static const struct file_operations dev_mem_ops = {
diff --git a/drivers/s390/char/vmur.c b/drivers/s390/char/vmur.c
index 0efb27f6f199..6c30e93ab8fa 100644
--- a/drivers/s390/char/vmur.c
+++ b/drivers/s390/char/vmur.c
@@ -782,24 +782,11 @@ static int ur_release(struct inode *inode, struct file *file)
 
 static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
 {
-	loff_t newpos;
-
 	if ((file->f_flags & O_ACCMODE) != O_RDONLY)
 		return -ESPIPE; /* seek allowed only for reader */
 	if (offset % PAGE_SIZE)
 		return -ESPIPE; /* only multiples of 4K allowed */
-	switch (whence) {
-	case 0: /* SEEK_SET */
-		newpos = offset;
-		break;
-	case 1: /* SEEK_CUR */
-		newpos = file->f_pos + offset;
-		break;
-	default:
-		return -EINVAL;
-	}
-	file->f_pos = newpos;
-	return newpos;
+	return no_seek_end_llseek(file, offset, whence);
 }
 
 static const struct file_operations ur_fops = {
diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 823f41fc4bbd..3339b862ec17 100644
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -385,18 +385,7 @@ static loff_t zcore_lseek(struct file *file, loff_t offset, int orig)
 	loff_t rc;
 
 	mutex_lock(&zcore_mutex);
-	switch (orig) {
-	case 0:
-		file->f_pos = offset;
-		rc = file->f_pos;
-		break;
-	case 1:
-		file->f_pos += offset;
-		rc = file->f_pos;
-		break;
-	default:
-		rc = -EINVAL;
-	}
+	rc = no_seek_end_llseek(file, offset, orig);
 	mutex_unlock(&zcore_mutex);
 	return rc;
 }
diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c
index 2a3bbdf7eb94..cffa0a0d7de2 100644
--- a/drivers/usb/core/devices.c
+++ b/drivers/usb/core/devices.c
@@ -661,32 +661,8 @@ static unsigned int usb_device_poll(struct file *file,
 	return 0;
 }
 
-static loff_t usb_device_lseek(struct file *file, loff_t offset, int orig)
-{
-	loff_t ret;
-
-	mutex_lock(&file_inode(file)->i_mutex);
-
-	switch (orig) {
-	case 0:
-		file->f_pos = offset;
-		ret = file->f_pos;
-		break;
-	case 1:
-		file->f_pos += offset;
-		ret = file->f_pos;
-		break;
-	case 2:
-	default:
-		ret = -EINVAL;
-	}
-
-	mutex_unlock(&file_inode(file)->i_mutex);
-	return ret;
-}
-
 const struct file_operations usbfs_devices_fops = {
-	.llseek =	usb_device_lseek,
+	.llseek =	no_seek_end_llseek,
 	.read =		usb_device_read,
 	.poll =		usb_device_poll,
 };
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 38ae877c46e3..dbc3e143453a 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -157,30 +157,6 @@ static int connected(struct usb_dev_state *ps)
 			ps->dev->state != USB_STATE_NOTATTACHED);
 }
 
-static loff_t usbdev_lseek(struct file *file, loff_t offset, int orig)
-{
-	loff_t ret;
-
-	mutex_lock(&file_inode(file)->i_mutex);
-
-	switch (orig) {
-	case 0:
-		file->f_pos = offset;
-		ret = file->f_pos;
-		break;
-	case 1:
-		file->f_pos += offset;
-		ret = file->f_pos;
-		break;
-	case 2:
-	default:
-		ret = -EINVAL;
-	}
-
-	mutex_unlock(&file_inode(file)->i_mutex);
-	return ret;
-}
-
 static ssize_t usbdev_read(struct file *file, char __user *buf, size_t nbytes,
 			   loff_t *ppos)
 {
@@ -2366,7 +2342,7 @@ static unsigned int usbdev_poll(struct file *file,
 
 const struct file_operations usbdev_file_operations = {
 	.owner =	  THIS_MODULE,
-	.llseek =	  usbdev_lseek,
+	.llseek =	  no_seek_end_llseek,
 	.read =		  usbdev_read,
 	.poll =		  usbdev_poll,
 	.unlocked_ioctl = usbdev_ioctl,
diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index 1b28a000d5c6..9c6635d43db0 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -584,27 +584,8 @@ static int uhci_debug_open(struct inode *inode, struct file *file)
 
 static loff_t uhci_debug_lseek(struct file *file, loff_t off, int whence)
 {
-	struct uhci_debug *up;
-	loff_t new = -1;
-
-	up = file->private_data;
-
-	/*
-	 * XXX: atomic 64bit seek access, but that needs to be fixed in the VFS
-	 */
-	switch (whence) {
-	case 0:
-		new = off;
-		break;
-	case 1:
-		new = file->f_pos + off;
-		break;
-	}
-
-	if (new < 0 || new > up->size)
-		return -EINVAL;
-
-	return (file->f_pos = new);
+	struct uhci_debug *up = file->private_data;
+	return no_seek_end_llseek_size(file, off, whence, up->size);
 }
 
 static ssize_t uhci_debug_read(struct file *file, char __user *buf,
diff --git a/drivers/usb/misc/sisusbvga/sisusb.c b/drivers/usb/misc/sisusbvga/sisusb.c
index 306d6852ebc7..8efbabacc84e 100644
--- a/drivers/usb/misc/sisusbvga/sisusb.c
+++ b/drivers/usb/misc/sisusbvga/sisusb.c
@@ -2825,21 +2825,7 @@ sisusb_lseek(struct file *file, loff_t offset, int orig)
 		return -ENODEV;
 	}
 
-	switch (orig) {
-		case 0:
-			file->f_pos = offset;
-			ret = file->f_pos;
-			/* never negative, no force_successful_syscall needed */
-			break;
-		case 1:
-			file->f_pos += offset;
-			ret = file->f_pos;
-			/* never negative, no force_successful_syscall needed */
-			break;
-		default:
-			/* seeking relative to "end of file" is not supported */
-			ret = -EINVAL;
-	}
+	ret = no_seek_end_llseek(file, offset, orig);
 
 	mutex_unlock(&sisusb->lock);
 	return ret;
diff --git a/fs/read_write.c b/fs/read_write.c
index 819ef3faf1bb..acb171331278 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -171,6 +171,45 @@ loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t si
 EXPORT_SYMBOL(fixed_size_llseek);
 
 /**
+ * no_seek_end_llseek - llseek implementation for fixed-sized devices
+ * @file:	file structure to seek on
+ * @offset:	file offset to seek to
+ * @whence:	type of seek
+ *
+ */
+loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
+{
+	switch (whence) {
+	case SEEK_SET: case SEEK_CUR:
+		return generic_file_llseek_size(file, offset, whence,
+						~0ULL, 0);
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL(no_seek_end_llseek);
+
+/**
+ * no_seek_end_llseek_size - llseek implementation for fixed-sized devices
+ * @file:	file structure to seek on
+ * @offset:	file offset to seek to
+ * @whence:	type of seek
+ * @size:	maximal offset allowed
+ *
+ */
+loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size)
+{
+	switch (whence) {
+	case SEEK_SET: case SEEK_CUR:
+		return generic_file_llseek_size(file, offset, whence,
+						size, 0);
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL(no_seek_end_llseek_size);
+
+/**
  * noop_llseek - No Operation Performed llseek implementation
  * @file:	file structure to seek on
  * @offset:	file offset to seek to
diff --git a/include/linux/fs.h b/include/linux/fs.h
index bd1447661e3c..fb0fa224d8e8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2660,6 +2660,8 @@ extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
 		int whence, loff_t maxsize, loff_t eof);
 extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
 		int whence, loff_t size);
+extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
+extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
 extern int generic_file_open(struct inode * inode, struct file * filp);
 extern int nonseekable_open(struct inode * inode, struct file * filp);