process_vm_access: tidy up a bit

saner variable names, update linuxdoc comments, etc. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

process_vm_access: tidy up a bit
saner variable names, update linuxdoc comments, etc. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro
1 parent 9acc1a0f9a
Showing 1 changed file with 19 additions and 40 deletions Side-by-side Diff
mm/process_vm_access.c
@@ -23,20 +23,11 @@
  
 /**
  * process_vm_rw_pages - read/write pages from task specified
- * @task: task to read/write from
- * @mm: mm for task
- * @process_pages: struct pages area that can store at least
- *  nr_pages_to_copy struct page pointers
- * @pa: address of page in task to start copying from/to
+ * @pages: array of pointers to pages we want to copy
  * @start_offset: offset in page to start copying from/to
  * @len: number of bytes to copy
- * @lvec: iovec array specifying where to copy to/from
- * @lvec_cnt: number of elements in iovec array
- * @lvec_current: index in iovec array we are up to
- * @lvec_offset: offset in bytes from current iovec iov_base we are up to
+ * @iter: where to copy to/from locally
  * @vm_write: 0 means copy from, 1 means copy to
- * @nr_pages_to_copy: number of pages to copy
- * @bytes_copied: returns number of bytes successfully copied
  * Returns 0 on success, error code otherwise
  */
 static int process_vm_rw_pages(struct page **pages,
  
@@ -79,16 +70,12 @@
  * process_vm_rw_single_vec - read/write pages from task specified
  * @addr: start memory address of target process
  * @len: size of area to copy to/from
- * @lvec: iovec array specifying where to copy to/from locally
- * @lvec_cnt: number of elements in iovec array
- * @lvec_current: index in iovec array we are up to
- * @lvec_offset: offset in bytes from current iovec iov_base we are up to
+ * @iter: where to copy to/from locally
  * @process_pages: struct pages area that can store at least
  *  nr_pages_to_copy struct page pointers
  * @mm: mm for task
  * @task: task to read/write from
  * @vm_write: 0 means copy from, 1 means copy to
- * @bytes_copied: returns number of bytes successfully copied
  * Returns 0 on success or on failure error code
  */
 static int process_vm_rw_single_vec(unsigned long addr,
@@ -103,7 +90,6 @@
 	unsigned long start_offset = addr - pa;
 	unsigned long nr_pages;
 	ssize_t rc = 0;
-	unsigned long nr_pages_copied = 0;
 	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
 		/ sizeof(struct pages *);
  
  
  
  
  
  
  
@@ -112,38 +98,32 @@
 		return 0;
 	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
  
-	while ((nr_pages_copied < nr_pages) && iov_iter_count(iter)) {
-		int nr_pages_to_copy;
-		int pages_pinned;
-		size_t n;
-		nr_pages_to_copy = min(nr_pages - nr_pages_copied,
-				       max_pages_per_loop);
+	while (!rc && nr_pages && iov_iter_count(iter)) {
+		int pages = min(nr_pages, max_pages_per_loop);
+		size_t bytes;
  
 		/* Get the pages we're interested in */
 		down_read(&mm->mmap_sem);
-		pages_pinned = get_user_pages(task, mm, pa,
-					      nr_pages_to_copy,
-					      vm_write, 0, process_pages, NULL);
+		pages = get_user_pages(task, mm, pa, pages,
+				      vm_write, 0, process_pages, NULL);
 		up_read(&mm->mmap_sem);
  
-		if (pages_pinned <= 0)
+		if (pages <= 0)
 			return -EFAULT;
  
-		n = pages_pinned * PAGE_SIZE - start_offset;
-		if (n > len)
-			n = len;
+		bytes = pages * PAGE_SIZE - start_offset;
+		if (bytes > len)
+			bytes = len;
  
 		rc = process_vm_rw_pages(process_pages,
-					 start_offset, n, iter,
+					 start_offset, bytes, iter,
 					 vm_write);
-		len -= n;
+		len -= bytes;
 		start_offset = 0;
-		nr_pages_copied += pages_pinned;
-		pa += pages_pinned * PAGE_SIZE;
-		while (pages_pinned)
-			put_page(process_pages[--pages_pinned]);
-		if (rc < 0)
-			break;
+		nr_pages -= pages;
+		pa += pages * PAGE_SIZE;
+		while (pages)
+			put_page(process_pages[--pages]);
 	}
  
 	return rc;
@@ -156,8 +136,7 @@
 /**
  * process_vm_rw_core - core of reading/writing pages from task specified
  * @pid: PID of process to read/write from/to
- * @lvec: iovec array specifying where to copy to/from locally
- * @liovcnt: size of lvec array
+ * @iter: where to copy to/from locally
  * @rvec: iovec array specifying where to copy to/from in the other process
  * @riovcnt: size of rvec array
  * @flags: currently unused
...	...	@@ -23,20 +23,11 @@
23	23
24	24	/**
25	25	* process_vm_rw_pages - read/write pages from task specified
26		- * @task: task to read/write from
27		- * @mm: mm for task
28		- * @process_pages: struct pages area that can store at least
29		- * nr_pages_to_copy struct page pointers
30		- * @pa: address of page in task to start copying from/to
	26	+ * @pages: array of pointers to pages we want to copy
31	27	* @start_offset: offset in page to start copying from/to
32	28	* @len: number of bytes to copy
33		- * @lvec: iovec array specifying where to copy to/from
34		- * @lvec_cnt: number of elements in iovec array
35		- * @lvec_current: index in iovec array we are up to
36		- * @lvec_offset: offset in bytes from current iovec iov_base we are up to
	29	+ * @iter: where to copy to/from locally
37	30	* @vm_write: 0 means copy from, 1 means copy to
38		- * @nr_pages_to_copy: number of pages to copy
39		- * @bytes_copied: returns number of bytes successfully copied
40	31	* Returns 0 on success, error code otherwise
41	32	*/
42	33	static int process_vm_rw_pages(struct page **pages,
43	34
...	...	@@ -79,16 +70,12 @@
79	70	* process_vm_rw_single_vec - read/write pages from task specified
80	71	* @addr: start memory address of target process
81	72	* @len: size of area to copy to/from
82		- * @lvec: iovec array specifying where to copy to/from locally
83		- * @lvec_cnt: number of elements in iovec array
84		- * @lvec_current: index in iovec array we are up to
85		- * @lvec_offset: offset in bytes from current iovec iov_base we are up to
	73	+ * @iter: where to copy to/from locally
86	74	* @process_pages: struct pages area that can store at least
87	75	* nr_pages_to_copy struct page pointers
88	76	* @mm: mm for task
89	77	* @task: task to read/write from
90	78	* @vm_write: 0 means copy from, 1 means copy to
91		- * @bytes_copied: returns number of bytes successfully copied
92	79	* Returns 0 on success or on failure error code
93	80	*/
94	81	static int process_vm_rw_single_vec(unsigned long addr,
...	...	@@ -103,7 +90,6 @@
103	90	unsigned long start_offset = addr - pa;
104	91	unsigned long nr_pages;
105	92	ssize_t rc = 0;
106		- unsigned long nr_pages_copied = 0;
107	93	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
108	94	/ sizeof(struct pages *);
109	95
110	96
111	97
112	98
113	99
114	100
115	101
...	...	@@ -112,38 +98,32 @@
112	98	return 0;
113	99	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
114	100
115		- while ((nr_pages_copied < nr_pages) && iov_iter_count(iter)) {
116		- int nr_pages_to_copy;
117		- int pages_pinned;
118		- size_t n;
119		- nr_pages_to_copy = min(nr_pages - nr_pages_copied,
120		- max_pages_per_loop);
	101	+ while (!rc && nr_pages && iov_iter_count(iter)) {
	102	+ int pages = min(nr_pages, max_pages_per_loop);
	103	+ size_t bytes;
121	104
122	105	/* Get the pages we're interested in */
123	106	down_read(&mm->mmap_sem);
124		- pages_pinned = get_user_pages(task, mm, pa,
125		- nr_pages_to_copy,
126		- vm_write, 0, process_pages, NULL);
	107	+ pages = get_user_pages(task, mm, pa, pages,
	108	+ vm_write, 0, process_pages, NULL);
127	109	up_read(&mm->mmap_sem);
128	110
129		- if (pages_pinned <= 0)
	111	+ if (pages <= 0)
130	112	return -EFAULT;
131	113
132		- n = pages_pinned * PAGE_SIZE - start_offset;
133		- if (n > len)
134		- n = len;
	114	+ bytes = pages * PAGE_SIZE - start_offset;
	115	+ if (bytes > len)
	116	+ bytes = len;
135	117
136	118	rc = process_vm_rw_pages(process_pages,
137		- start_offset, n, iter,
	119	+ start_offset, bytes, iter,
138	120	vm_write);
139		- len -= n;
	121	+ len -= bytes;
140	122	start_offset = 0;
141		- nr_pages_copied += pages_pinned;
142		- pa += pages_pinned * PAGE_SIZE;
143		- while (pages_pinned)
144		- put_page(process_pages[--pages_pinned]);
145		- if (rc < 0)
146		- break;
	123	+ nr_pages -= pages;
	124	+ pa += pages * PAGE_SIZE;
	125	+ while (pages)
	126	+ put_page(process_pages[--pages]);
147	127	}
148	128
149	129	return rc;
...	...	@@ -156,8 +136,7 @@
156	136	/**
157	137	* process_vm_rw_core - core of reading/writing pages from task specified
158	138	* @pid: PID of process to read/write from/to
159		- * @lvec: iovec array specifying where to copy to/from locally
160		- * @liovcnt: size of lvec array
	139	+ * @iter: where to copy to/from locally
161	140	* @rvec: iovec array specifying where to copy to/from in the other process
162	141	* @riovcnt: size of rvec array
163	142	* @flags: currently unused