splice: don't pass the address of ->f_pos to methods

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

splice: don't pass the address of ->f_pos to methods
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro
1 parent c9036e9f3b
Showing 5 changed files with 41 additions and 23 deletions Side-by-side Diff
fs/internal.h
fs/read_write.c
fs/splice.c
include/linux/fs.h
include/linux/splice.h
@@ -132,6 +132,12 @@
 extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
  
 /*
+ * splice.c
+ */
+extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
+		loff_t *opos, size_t len, unsigned int flags);
+
+/*
  * pipe.c
  */
 extern const struct file_operations pipefifo_fops;
@@ -1064,6 +1064,7 @@
 	struct fd in, out;
 	struct inode *in_inode, *out_inode;
 	loff_t pos;
+	loff_t out_pos;
 	ssize_t retval;
 	int fl;
  
  
@@ -1077,12 +1078,14 @@
 	if (!(in.file->f_mode & FMODE_READ))
 		goto fput_in;
 	retval = -ESPIPE;
-	if (!ppos)
-		ppos = &in.file->f_pos;
-	else
+	if (!ppos) {
+		pos = in.file->f_pos;
+	} else {
+		pos = *ppos;
 		if (!(in.file->f_mode & FMODE_PREAD))
 			goto fput_in;
-	retval = rw_verify_area(READ, in.file, ppos, count);
+	}
+	retval = rw_verify_area(READ, in.file, &pos, count);
 	if (retval < 0)
 		goto fput_in;
 	count = retval;
@@ -1099,7 +1102,8 @@
 	retval = -EINVAL;
 	in_inode = file_inode(in.file);
 	out_inode = file_inode(out.file);
-	retval = rw_verify_area(WRITE, out.file, &out.file->f_pos, count);
+	out_pos = out.file->f_pos;
+	retval = rw_verify_area(WRITE, out.file, &out_pos, count);
 	if (retval < 0)
 		goto fput_out;
 	count = retval;
@@ -1107,7 +1111,6 @@
 	if (!max)
 		max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
  
-	pos = *ppos;
 	if (unlikely(pos + count > max)) {
 		retval = -EOVERFLOW;
 		if (pos >= max)
  
  
@@ -1126,18 +1129,23 @@
 	if (in.file->f_flags & O_NONBLOCK)
 		fl = SPLICE_F_NONBLOCK;
 #endif
-	retval = do_splice_direct(in.file, ppos, out.file, count, fl);
+	retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
  
 	if (retval > 0) {
 		add_rchar(current, retval);
 		add_wchar(current, retval);
 		fsnotify_access(in.file);
 		fsnotify_modify(out.file);
+		out.file->f_pos = out_pos;
+		if (ppos)
+			*ppos = pos;
+		else
+			in.file->f_pos = pos;
 	}
  
 	inc_syscr(current);
 	inc_syscw(current);
-	if (*ppos > max)
+	if (pos > max)
 		retval = -EOVERFLOW;
  
 fput_out:
@@ -1274,7 +1274,7 @@
 {
 	struct file *file = sd->u.file;
  
-	return do_splice_from(pipe, file, &file->f_pos, sd->total_len,
+	return do_splice_from(pipe, file, sd->opos, sd->total_len,
 			      sd->flags);
 }
  
@@ -1294,7 +1294,7 @@
  *
  */
 long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
-		      size_t len, unsigned int flags)
+		      loff_t *opos, size_t len, unsigned int flags)
 {
 	struct splice_desc sd = {
 		.len		= len,
@@ -1302,6 +1302,7 @@
 		.flags		= flags,
 		.pos		= *ppos,
 		.u.file		= out,
+		.opos		= opos,
 	};
 	long ret;
  
@@ -1325,7 +1326,7 @@
 {
 	struct pipe_inode_info *ipipe;
 	struct pipe_inode_info *opipe;
-	loff_t offset, *off;
+	loff_t offset;
 	long ret;
  
 	ipipe = get_pipe_info(in);
  
  
@@ -1356,13 +1357,15 @@
 				return -EINVAL;
 			if (copy_from_user(&offset, off_out, sizeof(loff_t)))
 				return -EFAULT;
-			off = &offset;
-		} else
-			off = &out->f_pos;
+		} else {
+			offset = out->f_pos;
+		}
  
-		ret = do_splice_from(ipipe, out, off, len, flags);
+		ret = do_splice_from(ipipe, out, &offset, len, flags);
  
-		if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
+		if (!off_out)
+			out->f_pos = offset;
+		else if (copy_to_user(off_out, &offset, sizeof(loff_t)))
 			ret = -EFAULT;
  
 		return ret;
  
  
@@ -1376,13 +1379,15 @@
 				return -EINVAL;
 			if (copy_from_user(&offset, off_in, sizeof(loff_t)))
 				return -EFAULT;
-			off = &offset;
-		} else
-			off = &in->f_pos;
+		} else {
+			offset = in->f_pos;
+		}
  
-		ret = do_splice_to(in, off, opipe, len, flags);
+		ret = do_splice_to(in, &offset, opipe, len, flags);
  
-		if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
+		if (!off_in)
+			in->f_pos = offset;
+		else if (copy_to_user(off_in, &offset, sizeof(loff_t)))
 			ret = -EFAULT;
  
 		return ret;
@@ -2414,8 +2414,6 @@
 		struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
 		struct file *out, loff_t *, size_t len, unsigned int flags);
-extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
-		size_t len, unsigned int flags);
  
 extern void
 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
@@ -35,6 +35,7 @@
 		void *data;		/* cookie */
 	} u;
 	loff_t pos;			/* file position */
+	loff_t *opos;			/* sendfile: output position */
 	size_t num_spliced;		/* number of bytes already spliced */
 	bool need_wakeup;		/* need to wake up writer */
 };
...	...	@@ -132,6 +132,12 @@
132	132	extern ssize_t __kernel_write(struct file , const char , size_t, loff_t *);
133	133
134	134	/*
	135	+ * splice.c
	136	+ */
	137	+extern long do_splice_direct(struct file in, loff_t ppos, struct file *out,
	138	+ loff_t *opos, size_t len, unsigned int flags);
	139	+
	140	+/*
135	141	* pipe.c
136	142	*/
137	143	extern const struct file_operations pipefifo_fops;
...	...	@@ -1064,6 +1064,7 @@
1064	1064	struct fd in, out;
1065	1065	struct inode in_inode, out_inode;
1066	1066	loff_t pos;
	1067	+ loff_t out_pos;
1067	1068	ssize_t retval;
1068	1069	int fl;
1069	1070
1070	1071
...	...	@@ -1077,12 +1078,14 @@
1077	1078	if (!(in.file->f_mode & FMODE_READ))
1078	1079	goto fput_in;
1079	1080	retval = -ESPIPE;
1080		- if (!ppos)
1081		- ppos = &in.file->f_pos;
1082		- else
	1081	+ if (!ppos) {
	1082	+ pos = in.file->f_pos;
	1083	+ } else {
	1084	+ pos = *ppos;
1083	1085	if (!(in.file->f_mode & FMODE_PREAD))
1084	1086	goto fput_in;
1085		- retval = rw_verify_area(READ, in.file, ppos, count);
	1087	+ }
	1088	+ retval = rw_verify_area(READ, in.file, &pos, count);
1086	1089	if (retval < 0)
1087	1090	goto fput_in;
1088	1091	count = retval;
...	...	@@ -1099,7 +1102,8 @@
1099	1102	retval = -EINVAL;
1100	1103	in_inode = file_inode(in.file);
1101	1104	out_inode = file_inode(out.file);
1102		- retval = rw_verify_area(WRITE, out.file, &out.file->f_pos, count);
	1105	+ out_pos = out.file->f_pos;
	1106	+ retval = rw_verify_area(WRITE, out.file, &out_pos, count);
1103	1107	if (retval < 0)
1104	1108	goto fput_out;
1105	1109	count = retval;
...	...	@@ -1107,7 +1111,6 @@
1107	1111	if (!max)
1108	1112	max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
1109	1113
1110		- pos = *ppos;
1111	1114	if (unlikely(pos + count > max)) {
1112	1115	retval = -EOVERFLOW;
1113	1116	if (pos >= max)
1114	1117
1115	1118
...	...	@@ -1126,18 +1129,23 @@
1126	1129	if (in.file->f_flags & O_NONBLOCK)
1127	1130	fl = SPLICE_F_NONBLOCK;
1128	1131	#endif
1129		- retval = do_splice_direct(in.file, ppos, out.file, count, fl);
	1132	+ retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
1130	1133
1131	1134	if (retval > 0) {
1132	1135	add_rchar(current, retval);
1133	1136	add_wchar(current, retval);
1134	1137	fsnotify_access(in.file);
1135	1138	fsnotify_modify(out.file);
	1139	+ out.file->f_pos = out_pos;
	1140	+ if (ppos)
	1141	+ *ppos = pos;
	1142	+ else
	1143	+ in.file->f_pos = pos;
1136	1144	}
1137	1145
1138	1146	inc_syscr(current);
1139	1147	inc_syscw(current);
1140		- if (*ppos > max)
	1148	+ if (pos > max)
1141	1149	retval = -EOVERFLOW;
1142	1150
1143	1151	fput_out:
...	...	@@ -1274,7 +1274,7 @@
1274	1274	{
1275	1275	struct file *file = sd->u.file;
1276	1276
1277		- return do_splice_from(pipe, file, &file->f_pos, sd->total_len,
	1277	+ return do_splice_from(pipe, file, sd->opos, sd->total_len,
1278	1278	sd->flags);
1279	1279	}
1280	1280
...	...	@@ -1294,7 +1294,7 @@
1294	1294	*
1295	1295	*/
1296	1296	long do_splice_direct(struct file in, loff_t ppos, struct file *out,
1297		- size_t len, unsigned int flags)
	1297	+ loff_t *opos, size_t len, unsigned int flags)
1298	1298	{
1299	1299	struct splice_desc sd = {
1300	1300	.len = len,
...	...	@@ -1302,6 +1302,7 @@
1302	1302	.flags = flags,
1303	1303	.pos = *ppos,
1304	1304	.u.file = out,
	1305	+ .opos = opos,
1305	1306	};
1306	1307	long ret;
1307	1308
...	...	@@ -1325,7 +1326,7 @@
1325	1326	{
1326	1327	struct pipe_inode_info *ipipe;
1327	1328	struct pipe_inode_info *opipe;
1328		- loff_t offset, *off;
	1329	+ loff_t offset;
1329	1330	long ret;
1330	1331
1331	1332	ipipe = get_pipe_info(in);
1332	1333
1333	1334
...	...	@@ -1356,13 +1357,15 @@
1356	1357	return -EINVAL;
1357	1358	if (copy_from_user(&offset, off_out, sizeof(loff_t)))
1358	1359	return -EFAULT;
1359		- off = &offset;
1360		- } else
1361		- off = &out->f_pos;
	1360	+ } else {
	1361	+ offset = out->f_pos;
	1362	+ }
1362	1363
1363		- ret = do_splice_from(ipipe, out, off, len, flags);
	1364	+ ret = do_splice_from(ipipe, out, &offset, len, flags);
1364	1365
1365		- if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
	1366	+ if (!off_out)
	1367	+ out->f_pos = offset;
	1368	+ else if (copy_to_user(off_out, &offset, sizeof(loff_t)))
1366	1369	ret = -EFAULT;
1367	1370
1368	1371	return ret;
1369	1372
1370	1373
...	...	@@ -1376,13 +1379,15 @@
1376	1379	return -EINVAL;
1377	1380	if (copy_from_user(&offset, off_in, sizeof(loff_t)))
1378	1381	return -EFAULT;
1379		- off = &offset;
1380		- } else
1381		- off = &in->f_pos;
	1382	+ } else {
	1383	+ offset = in->f_pos;
	1384	+ }
1382	1385
1383		- ret = do_splice_to(in, off, opipe, len, flags);
	1386	+ ret = do_splice_to(in, &offset, opipe, len, flags);
1384	1387
1385		- if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
	1388	+ if (!off_in)
	1389	+ in->f_pos = offset;
	1390	+ else if (copy_to_user(off_in, &offset, sizeof(loff_t)))
1386	1391	ret = -EFAULT;
1387	1392
1388	1393	return ret;
...	...	@@ -2414,8 +2414,6 @@
2414	2414	struct file , loff_t , size_t, unsigned int);
2415	2415	extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
2416	2416	struct file out, loff_t , size_t len, unsigned int flags);
2417		-extern long do_splice_direct(struct file in, loff_t ppos, struct file *out,
2418		- size_t len, unsigned int flags);
2419	2417
2420	2418	extern void
2421	2419	file_ra_state_init(struct file_ra_state ra, struct address_space mapping);
...	...	@@ -35,6 +35,7 @@
35	35	void data; / cookie */
36	36	} u;
37	37	loff_t pos; /* file position */
	38	+ loff_t opos; / sendfile: output position */
38	39	size_t num_spliced; /* number of bytes already spliced */
39	40	bool need_wakeup; /* need to wake up writer */
40	41	};