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>

9 files changed, 43 insertions, 45 deletions

diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index 9be82c4e14a4..ce1824f47ba6 100644
--- a/fs/binfmt_aout.c
+++ b/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;
 
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 6466153f2bf0..2f928b87c90e 100644
--- a/fs/binfmt_elf.c
+++ b/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;
 
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index cf93a4fad012..b4ebfe203a68 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/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;
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index a1e6860b6f46..afb7e9d521d2 100644
--- a/fs/binfmt_flat.c
+++ b/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) {
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index f4718098ac31..ce7181ea60fa 100644
--- a/fs/binfmt_misc.c
+++ b/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);
 
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index c0474ac6cbf2..274ab5586dd0 100644
--- a/fs/coda/dir.c
+++ b/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);
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 039e627194a9..d8af0e99bfaf 100644
--- a/fs/ecryptfs/read_write.c
+++ b/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);
 }
 
 /**
diff --git a/fs/exec.c b/fs/exec.c
index 8adcc5eaa175..15fb4d56cc43 100644
--- a/fs/exec.c
+++ b/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);
diff --git a/fs/read_write.c b/fs/read_write.c
index 1ea862bc7efd..9cf1de855b7a 100644
--- a/fs/read_write.c
+++ b/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;
 }