kernel/fs: Use the new fd_readv/fd_writev hooks in common_vector_io.

And move the file_readv/file_writev implementation to the VFS.

src/system/kernel/fs/fd.cpp

@@ -29,7 +29,6 @@
 #include <vfs.h>
 #include <wait_for_objects.h>
 
-#include "Vnode.h"
 #include "vfs_tracing.h"
 
 
@@ -709,30 +708,22 @@ common_vector_io(int fd, off_t pos, const iovec* vecs, size_t count, bool write,
 		return B_BAD_VALUE;
 	}
 
-	// See if we can bypass the loop and perform I/O directly. We can only do this
-	// for vnodes that have no cache, as the I/O hook bypasses the cache entirely.
-	struct vnode* vnode = descriptor->u.vnode;
-	status_t status = B_OK;
-	if (!movePosition && pos != -1 && count > 1 && fd_is_file(descriptor.Get())
-			&& vnode != NULL && vnode->cache == NULL && vnode->ops->io != NULL) {
-		BStackOrHeapArray<generic_io_vec, 8> iovecs(count);
-		if (!iovecs.IsValid())
-			return B_NO_MEMORY;
-
-		generic_size_t length = 0;
-		for (size_t i = 0; i < count; i++) {
-			iovecs[i].base = (generic_addr_t)vecs[i].iov_base;
-			iovecs[i].length = vecs[i].iov_len;
-			length += vecs[i].iov_len;
+	if (!movePosition && count > 1 && (write ? descriptor->ops->fd_writev != NULL
+			: descriptor->ops->fd_readv != NULL)) {
+		ssize_t result;
+		if (write) {
+			result = descriptor->ops->fd_writev(descriptor.Get(), pos,
+				vecs, count);
+		} else {
+			result = descriptor->ops->fd_readv(descriptor.Get(), pos,
+				vecs, count);
 		}
-
-		status = (write ? vfs_write_pages : vfs_read_pages)(vnode,
-			descriptor->cookie, pos, iovecs, count, 0, &length);
-		if (length > 0)
-			return length;
-		return status;
+		if (result != B_UNSUPPORTED)
+			return result;
+		// If not supported, just fall back to the loop.
 	}
 
+	status_t status = B_OK;
 	ssize_t bytesTransferred = 0;
 	for (size_t i = 0; i < count; i++) {
 		if (vecs[i].iov_base == NULL)
@@ -743,8 +734,8 @@ common_vector_io(int fd, off_t pos, const iovec* vecs, size_t count, bool write,
 			status = descriptor->ops->fd_write(descriptor.Get(), pos,
 				vecs[i].iov_base, &length);
 		} else {
-			status = descriptor->ops->fd_read(descriptor.Get(), pos, vecs[i].iov_base,
-				&length);
+			status = descriptor->ops->fd_read(descriptor.Get(), pos,
+				vecs[i].iov_base, &length);
 		}
 
 		if (status != B_OK) {

src/system/kernel/fs/vfs.cpp

@@ -358,6 +358,10 @@ static status_t file_read(struct file_descriptor* descriptor, off_t pos,
 	void* buffer, size_t* _bytes);
 static status_t file_write(struct file_descriptor* descriptor, off_t pos,
 	const void* buffer, size_t* _bytes);
+static ssize_t file_readv(struct file_descriptor* descriptor, off_t pos,
+	const struct iovec *vecs, int count);
+static ssize_t file_writev(struct file_descriptor* descriptor, off_t pos,
+	const struct iovec *vecs, int count);
 static off_t file_seek(struct file_descriptor* descriptor, off_t pos,
 	int seekType);
 static void file_free_fd(struct file_descriptor* descriptor);
@@ -435,8 +439,8 @@ static struct fd_ops sFileOps = {
 	file_free_fd,
 	file_read,
 	file_write,
-	NULL,		// readv()
-	NULL,		// writev()
+	file_readv,
+	file_writev,
 	file_seek,
 	common_ioctl,
 	NULL,		// set_flags()
@@ -5725,6 +5729,63 @@ file_write(struct file_descriptor* descriptor, off_t pos, const void* buffer,
 }
 
 
+static ssize_t
+file_vector_io(struct file_descriptor* descriptor, off_t pos,
+	const struct iovec *vecs, int count, bool write)
+{
+	struct vnode* vnode = descriptor->u.vnode;
+	if (pos != -1 && descriptor->pos == -1)
+		return ESPIPE;
+	if (S_ISDIR(vnode->Type()))
+		return B_IS_A_DIRECTORY;
+
+	if (pos == -1)
+		return B_UNSUPPORTED;
+	if (!HAS_FS_CALL(vnode, io))
+		return B_UNSUPPORTED;
+
+	// We can only perform real vectored I/O for vnodes that have no cache,
+	// because the I/O hook bypasses the cache entirely.
+	if (vnode->cache != NULL)
+		return B_UNSUPPORTED;
+
+	BStackOrHeapArray<generic_io_vec, 8> iovecs(count);
+	if (!iovecs.IsValid())
+		return B_NO_MEMORY;
+
+	generic_size_t length = 0;
+	for (int i = 0; i < count; i++) {
+		iovecs[i].base = (generic_addr_t)vecs[i].iov_base;
+		iovecs[i].length = vecs[i].iov_len;
+		length += vecs[i].iov_len;
+	}
+
+	status_t status = (write ? vfs_write_pages : vfs_read_pages)(vnode,
+		descriptor->cookie, pos, iovecs, count, 0, &length);
+	if (length > 0)
+		return length;
+	return status;
+}
+
+
+static ssize_t
+file_readv(struct file_descriptor* descriptor, off_t pos,
+	const struct iovec *vecs, int count)
+{
+	FUNCTION(("file_readv: pos %" B_PRIdOFF "\n", pos));
+	return file_vector_io(descriptor, pos, vecs, count, false);
+}
+
+
+static ssize_t
+file_writev(struct file_descriptor* descriptor, off_t pos,
+	const struct iovec *vecs, int count)
+{
+	FUNCTION(("file_writev: pos %" B_PRIdOFF "\n", pos));
+	return file_vector_io(descriptor, pos, vecs, count, true);
+}
+
+
 static off_t
 file_seek(struct file_descriptor* descriptor, off_t pos, int seekType)
 {