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-rw-r--r--mm/process_vm_access.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 0523edab03a6..b308e96cd05a 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -53,7 +53,10 @@ static int process_vm_rw_pages(struct page **pages,
}
/* Maximum number of pages kmalloc'd to hold struct page's during copy */
-#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)
+#define PVM_MAX_KMALLOC_PAGES 2
+
+/* Maximum number of pages that can be stored at a time */
+#define PVM_MAX_USER_PAGES (PVM_MAX_KMALLOC_PAGES * PAGE_SIZE / sizeof(struct page *))
/**
* process_vm_rw_single_vec - read/write pages from task specified
@@ -79,8 +82,6 @@ static int process_vm_rw_single_vec(unsigned long addr,
unsigned long start_offset = addr - pa;
unsigned long nr_pages;
ssize_t rc = 0;
- unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
- / sizeof(struct pages *);
unsigned int flags = 0;
/* Work out address and page range required */
@@ -92,7 +93,7 @@ static int process_vm_rw_single_vec(unsigned long addr,
flags |= FOLL_WRITE;
while (!rc && nr_pages && iov_iter_count(iter)) {
- int pinned_pages = min(nr_pages, max_pages_per_loop);
+ int pinned_pages = min_t(unsigned long, nr_pages, PVM_MAX_USER_PAGES);
int locked = 1;
size_t bytes;
@@ -171,7 +172,7 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
iov_len = rvec[i].iov_len;
if (iov_len > 0) {
nr_pages_iov = ((unsigned long)rvec[i].iov_base
- + iov_len)
+ + iov_len - 1)
/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
/ PAGE_SIZE + 1;
nr_pages = max(nr_pages, nr_pages_iov);
@@ -184,8 +185,8 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
/* For reliability don't try to kmalloc more than
2 pages worth */
- process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
- sizeof(struct pages *)*nr_pages),
+ process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES * PAGE_SIZE,
+ sizeof(struct page *)*nr_pages),
GFP_KERNEL);
if (!process_pages)