fs: fix kernel_read prototype

Use proper ssize_t and size_t types for the return value and count
argument, move the offset last and make it an in/out argument like
all other read/write helpers, and make the buf argument a void pointer
to get rid of lots of casts in the callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/mips/kernel/elf.c

@@ -87,6 +87,7 @@ int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
 	bool elf32;
 	u32 flags;
 	int ret;
+	loff_t pos;
 
 	elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
 	flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
@@ -108,21 +109,16 @@ int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
 
 		if (phdr32->p_filesz < sizeof(abiflags))
 			return -EINVAL;
-
-		ret = kernel_read(elf, phdr32->p_offset,
-				  (char *)&abiflags,
-				  sizeof(abiflags));
+		pos = phdr32->p_offset;
 	} else {
 		if (phdr64->p_type != PT_MIPS_ABIFLAGS)
 			return 0;
 		if (phdr64->p_filesz < sizeof(abiflags))
 			return -EINVAL;
-
-		ret = kernel_read(elf, phdr64->p_offset,
-				  (char *)&abiflags,
-				  sizeof(abiflags));
+		pos = phdr64->p_offset;
 	}
 
+	ret = kernel_read(elf, &abiflags, sizeof(abiflags), &pos);
 	if (ret < 0)
 		return ret;
 	if (ret != sizeof(abiflags))

arch/x86/ia32/ia32_aout.c

@@ -407,10 +407,10 @@ static int load_aout_library(struct file *file)
 	unsigned long bss, start_addr, len, error;
 	int retval;
 	struct exec ex;
-
+	loff_t pos = 0;
 
 	retval = -ENOEXEC;
-	error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
+	error = kernel_read(file, &ex, sizeof(ex), &pos);
 	if (error != sizeof(ex))
 		goto out;
 

drivers/media/pci/cx25821/cx25821-audio-upstream.c

@@ -277,7 +277,7 @@ static int cx25821_get_audio_data(struct cx25821_dev *dev,
 		p = (char *)dev->_audiodata_buf_virt_addr + frame_offset;
 
 	for (i = 0; i < dev->_audio_lines_count; i++) {
-		int n = kernel_read(file, file_offset, mybuf, AUDIO_LINE_SIZE);
+		int n = kernel_read(file, mybuf, AUDIO_LINE_SIZE, &file_offset);
 		if (n < AUDIO_LINE_SIZE) {
 			pr_info("Done: exit %s() since no more bytes to read from Audio file\n",
 				__func__);
@@ -290,7 +290,6 @@ static int cx25821_get_audio_data(struct cx25821_dev *dev,
 			memcpy(p, mybuf, n);
 			p += n;
 		}
-		file_offset += n;
 	}
 	dev->_audioframe_count++;
 	fput(file);
@@ -318,7 +317,7 @@ static int cx25821_openfile_audio(struct cx25821_dev *dev,
 {
 	char *p = (void *)dev->_audiodata_buf_virt_addr;
 	struct file *file;
-	loff_t offset;
+	loff_t file_offset = 0;
 	int i, j;
 
 	file = filp_open(dev->_audiofilename, O_RDONLY | O_LARGEFILE, 0);
@@ -328,11 +327,11 @@ static int cx25821_openfile_audio(struct cx25821_dev *dev,
 		return PTR_ERR(file);
 	}
 
-	for (j = 0, offset = 0; j < NUM_AUDIO_FRAMES; j++) {
+	for (j = 0; j < NUM_AUDIO_FRAMES; j++) {
 		for (i = 0; i < dev->_audio_lines_count; i++) {
 			char buf[AUDIO_LINE_SIZE];
-			int n = kernel_read(file, offset, buf,
-						AUDIO_LINE_SIZE);
+			loff_t offset = file_offset;
+			int n = kernel_read(file, buf, AUDIO_LINE_SIZE, &file_offset);
 
 			if (n < AUDIO_LINE_SIZE) {
 				pr_info("Done: exit %s() since no more bytes to read from Audio file\n",
@@ -344,8 +343,6 @@ static int cx25821_openfile_audio(struct cx25821_dev *dev,
 
 			if (p)
 				memcpy(p + offset, buf, n);
-
-			offset += n;
 		}
 		dev->_audioframe_count++;
 	}

drivers/mtd/nand/nandsim.c

@@ -1379,7 +1379,7 @@ static ssize_t read_file(struct nandsim *ns, struct file *file, void *buf, size_
 	if (err)
 		return err;
 	noreclaim_flag = memalloc_noreclaim_save();
-	tx = kernel_read(file, pos, buf, count);
+	tx = kernel_read(file, buf, count, &pos);
 	memalloc_noreclaim_restore(noreclaim_flag);
 	put_pages(ns);
 	return tx;

fs/binfmt_aout.c

@@ -341,11 +341,12 @@ static int load_aout_library(struct file *file)
 	unsigned long error;
 	int retval;
 	struct exec ex;
+	loff_t pos = 0;
 
 	inode = file_inode(file);
 
 	retval = -ENOEXEC;
-	error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
+	error = kernel_read(file, &ex, sizeof(ex), &pos);
 	if (error != sizeof(ex))
 		goto out;
 

fs/binfmt_elf.c

@@ -409,6 +409,7 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
 {
 	struct elf_phdr *elf_phdata = NULL;
 	int retval, size, err = -1;
+	loff_t pos = elf_ex->e_phoff;
 
 	/*
 	 * If the size of this structure has changed, then punt, since
@@ -432,8 +433,7 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
 		goto out;
 
 	/* Read in the program headers */
-	retval = kernel_read(elf_file, elf_ex->e_phoff,
-			     (char *)elf_phdata, size);
+	retval = kernel_read(elf_file, elf_phdata, size, &pos);
 	if (retval != size) {
 		err = (retval < 0) ? retval : -EIO;
 		goto out;
@@ -698,6 +698,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		struct elfhdr interp_elf_ex;
 	} *loc;
 	struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
+	loff_t pos;
 
 	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
 	if (!loc) {
@@ -750,9 +751,9 @@ static int load_elf_binary(struct linux_binprm *bprm)
 			if (!elf_interpreter)
 				goto out_free_ph;
 
-			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
-					     elf_interpreter,
-					     elf_ppnt->p_filesz);
+			pos = elf_ppnt->p_offset;
+			retval = kernel_read(bprm->file, elf_interpreter,
+					     elf_ppnt->p_filesz, &pos);
 			if (retval != elf_ppnt->p_filesz) {
 				if (retval >= 0)
 					retval = -EIO;
@@ -776,9 +777,9 @@ static int load_elf_binary(struct linux_binprm *bprm)
 			would_dump(bprm, interpreter);
 
 			/* Get the exec headers */
-			retval = kernel_read(interpreter, 0,
-					     (void *)&loc->interp_elf_ex,
-					     sizeof(loc->interp_elf_ex));
+			pos = 0;
+			retval = kernel_read(interpreter, &loc->interp_elf_ex,
+					     sizeof(loc->interp_elf_ex), &pos);
 			if (retval != sizeof(loc->interp_elf_ex)) {
 				if (retval >= 0)
 					retval = -EIO;
@@ -1175,9 +1176,10 @@ static int load_elf_library(struct file *file)
 	unsigned long elf_bss, bss, len;
 	int retval, error, i, j;
 	struct elfhdr elf_ex;
+	loff_t pos = 0;
 
 	error = -ENOEXEC;
-	retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
+	retval = kernel_read(file, &elf_ex, sizeof(elf_ex), &pos);
 	if (retval != sizeof(elf_ex))
 		goto out;
 
@@ -1201,7 +1203,8 @@ static int load_elf_library(struct file *file)
 
 	eppnt = elf_phdata;
 	error = -ENOEXEC;
-	retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
+	pos =  elf_ex.e_phoff;
+	retval = kernel_read(file, eppnt, j, &pos);
 	if (retval != j)
 		goto out_free_ph;
 

fs/binfmt_elf_fdpic.c

@@ -145,6 +145,7 @@ static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
 	struct elf32_phdr *phdr;
 	unsigned long size;
 	int retval, loop;
+	loff_t pos = params->hdr.e_phoff;
 
 	if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
 		return -ENOMEM;
@@ -156,8 +157,7 @@ static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
 	if (!params->phdrs)
 		return -ENOMEM;
 
-	retval = kernel_read(file, params->hdr.e_phoff,
-			     (char *) params->phdrs, size);
+	retval = kernel_read(file, params->phdrs, size, &pos);
 	if (unlikely(retval != size))
 		return retval < 0 ? retval : -ENOEXEC;
 
@@ -199,6 +199,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 	char *interpreter_name = NULL;
 	int executable_stack;
 	int retval, i;
+	loff_t pos;
 
 	kdebug("____ LOAD %d ____", current->pid);
 
@@ -246,10 +247,9 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 			if (!interpreter_name)
 				goto error;
 
-			retval = kernel_read(bprm->file,
-					     phdr->p_offset,
-					     interpreter_name,
-					     phdr->p_filesz);
+			pos = phdr->p_offset;
+			retval = kernel_read(bprm->file, interpreter_name,
+					     phdr->p_filesz, &pos);
 			if (unlikely(retval != phdr->p_filesz)) {
 				if (retval >= 0)
 					retval = -ENOEXEC;
@@ -277,8 +277,9 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 			 */
 			would_dump(bprm, interpreter);
 
-			retval = kernel_read(interpreter, 0, bprm->buf,
-					     BINPRM_BUF_SIZE);
+			pos = 0;
+			retval = kernel_read(interpreter, bprm->buf,
+					BINPRM_BUF_SIZE, &pos);
 			if (unlikely(retval != BINPRM_BUF_SIZE)) {
 				if (retval >= 0)
 					retval = -ENOEXEC;

fs/binfmt_flat.c

@@ -176,19 +176,14 @@ static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start
 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 
-static int decompress_exec(
-	struct linux_binprm *bprm,
-	unsigned long offset,
-	char *dst,
-	long len,
-	int fd)
+static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,
+		long len, int fd)
 {
 	unsigned char *buf;
 	z_stream strm;
-	loff_t fpos;
 	int ret, retval;
 
-	pr_debug("decompress_exec(offset=%lx,buf=%p,len=%lx)\n", offset, dst, len);
+	pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);
 
 	memset(&strm, 0, sizeof(strm));
 	strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
@@ -204,13 +199,11 @@ static int decompress_exec(
 	}
 
 	/* Read in first chunk of data and parse gzip header. */
-	fpos = offset;
-	ret = kernel_read(bprm->file, offset, buf, LBUFSIZE);
+	ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
 
 	strm.next_in = buf;
 	strm.avail_in = ret;
 	strm.total_in = 0;
-	fpos += ret;
 
 	retval = -ENOEXEC;
 
@@ -276,7 +269,7 @@ static int decompress_exec(
 	}
 
 	while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
-		ret = kernel_read(bprm->file, fpos, buf, LBUFSIZE);
+		ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
 		if (ret <= 0)
 			break;
 		len -= ret;
@@ -284,7 +277,6 @@ static int decompress_exec(
 		strm.next_in = buf;
 		strm.avail_in = ret;
 		strm.total_in = 0;
-		fpos += ret;
 	}
 
 	if (ret < 0) {

fs/binfmt_misc.c

@@ -218,12 +218,15 @@ static int load_misc_binary(struct linux_binprm *bprm)
 
 	bprm->file = interp_file;
 	if (fmt->flags & MISC_FMT_CREDENTIALS) {
+		loff_t pos = 0;
+
 		/*
 		 * No need to call prepare_binprm(), it's already been
 		 * done.  bprm->buf is stale, update from interp_file.
 		 */
 		memset(bprm->buf, 0, BINPRM_BUF_SIZE);
-		retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
+		retval = kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE,
+				&pos);
 	} else
 		retval = prepare_binprm(bprm);
 

fs/coda/dir.c

@@ -368,9 +368,10 @@ static int coda_venus_readdir(struct file *coda_file, struct dir_context *ctx)
 		goto out;
 
 	while (1) {
+		loff_t pos = ctx->pos - 2;
+
 		/* read entries from the directory file */
-		ret = kernel_read(host_file, ctx->pos - 2, (char *)vdir,
-				  sizeof(*vdir));
+		ret = kernel_read(host_file, vdir, sizeof(*vdir), &pos);
 		if (ret < 0) {
 			pr_err("%s: read dir %s failed %d\n",
 			       __func__, coda_f2s(&cii->c_fid), ret);

fs/ecryptfs/read_write.c

@@ -237,7 +237,7 @@ int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
 	lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file;
 	if (!lower_file)
 		return -EIO;
-	return kernel_read(lower_file, offset, data, size);
+	return kernel_read(lower_file, data, size, &offset);
 }
 
 /**

fs/exec.c

@@ -922,8 +922,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 
 	pos = 0;
 	while (pos < i_size) {
-		bytes = kernel_read(file, pos, (char *)(*buf) + pos,
-				    i_size - pos);
+		bytes = kernel_read(file, *buf + pos, i_size - pos, &pos);
 		if (bytes < 0) {
 			ret = bytes;
 			goto out;
@@ -931,7 +930,6 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 
 		if (bytes == 0)
 			break;
-		pos += bytes;
 	}
 
 	if (pos != i_size) {
@@ -1524,6 +1522,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm)
 int prepare_binprm(struct linux_binprm *bprm)
 {
 	int retval;
+	loff_t pos = 0;
 
 	bprm_fill_uid(bprm);
 
@@ -1534,7 +1533,7 @@ int prepare_binprm(struct linux_binprm *bprm)
 	bprm->cred_prepared = 1;
 
 	memset(bprm->buf, 0, BINPRM_BUF_SIZE);
-	return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
+	return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos);
 }
 
 EXPORT_SYMBOL(prepare_binprm);

fs/read_write.c

@@ -415,17 +415,15 @@ ssize_t __vfs_read(struct file *file, char __user *buf, size_t count,
 }
 EXPORT_SYMBOL(__vfs_read);
 
-int kernel_read(struct file *file, loff_t offset, char *addr,
-		unsigned long count)
+ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
 {
 	mm_segment_t old_fs;
-	loff_t pos = offset;
-	int result;
+	ssize_t result;
 
 	old_fs = get_fs();
 	set_fs(get_ds());
 	/* The cast to a user pointer is valid due to the set_fs() */
-	result = vfs_read(file, (void __user *)addr, count, &pos);
+	result = vfs_read(file, (void __user *)buf, count, pos);
 	set_fs(old_fs);
 	return result;
 }

include/linux/fs.h

@@ -2772,13 +2772,13 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 	return kernel_read_file_str[id];
 }
 
-extern int kernel_read(struct file *, loff_t, char *, unsigned long);
 extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
 			    enum kernel_read_file_id);
 extern int kernel_read_file_from_path(char *, void **, loff_t *, loff_t,
 				      enum kernel_read_file_id);
 extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
 				    enum kernel_read_file_id);
+extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
 extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
 extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
 extern struct file * open_exec(const char *);

kernel/sysctl_binary.c

@@ -986,8 +986,9 @@ static ssize_t bin_intvec(struct file *file,
 		size_t length = oldlen / sizeof(*vec);
 		char *str, *end;
 		int i;
+		loff_t pos = 0;
 
-		result = kernel_read(file, 0, buffer, BUFSZ - 1);
+		result = kernel_read(file, buffer, BUFSZ - 1, &pos);
 		if (result < 0)
 			goto out_kfree;
 
@@ -1057,8 +1058,9 @@ static ssize_t bin_ulongvec(struct file *file,
 		size_t length = oldlen / sizeof(*vec);
 		char *str, *end;
 		int i;
+		loff_t pos = 0;
 
-		result = kernel_read(file, 0, buffer, BUFSZ - 1);
+		result = kernel_read(file, buffer, BUFSZ - 1, &pos);
 		if (result < 0)
 			goto out_kfree;
 
@@ -1120,8 +1122,9 @@ static ssize_t bin_uuid(struct file *file,
 	if (oldval && oldlen) {
 		char buf[UUID_STRING_LEN + 1];
 		uuid_t uuid;
+		loff_t pos = 0;
 
-		result = kernel_read(file, 0, buf, sizeof(buf) - 1);
+		result = kernel_read(file, buf, sizeof(buf) - 1, &pos);
 		if (result < 0)
 			goto out;
 
@@ -1154,8 +1157,9 @@ static ssize_t bin_dn_node_address(struct file *file,
 		char buf[15], *nodep;
 		unsigned long area, node;
 		__le16 dnaddr;
+		loff_t pos = 0;
 
-		result = kernel_read(file, 0, buf, sizeof(buf) - 1);
+		result = kernel_read(file, buf, sizeof(buf) - 1, &pos);
 		if (result < 0)
 			goto out;
 

net/9p/trans_fd.c

@@ -272,6 +272,7 @@ static int p9_fd_read(struct p9_client *client, void *v, int len)
 {
 	int ret;
 	struct p9_trans_fd *ts = NULL;
+	loff_t pos;
 
 	if (client && client->status != Disconnected)
 		ts = client->trans;
@@ -282,7 +283,8 @@ static int p9_fd_read(struct p9_client *client, void *v, int len)
 	if (!(ts->rd->f_flags & O_NONBLOCK))
 		p9_debug(P9_DEBUG_ERROR, "blocking read ...\n");
 
-	ret = kernel_read(ts->rd, ts->rd->f_pos, v, len);
+	pos = ts->rd->f_pos;
+	ret = kernel_read(ts->rd, v, len, &pos);
 	if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
 		client->status = Disconnected;
 	return ret;

security/keys/big_key.c

@@ -295,6 +295,7 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
 		u8 *data;
 		u8 *enckey = (u8 *)key->payload.data[big_key_data];
 		size_t enclen = ALIGN(datalen, crypto_skcipher_blocksize(big_key_skcipher));
+		loff_t pos = 0;
 
 		data = kmalloc(enclen, GFP_KERNEL);
 		if (!data)
@@ -307,7 +308,7 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
 		}
 
 		/* read file to kernel and decrypt */
-		ret = kernel_read(file, 0, data, enclen);
+		ret = kernel_read(file, data, enclen, &pos);
 		if (ret >= 0 && ret != enclen) {
 			ret = -EIO;
 			goto err_fput;