Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter cleanups from Al Viro.

* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fold checks into iterate_and_advance()
  rw_verify_area(): saner calling conventions
  aio: remove a pointless assignment

3 files changed, 50 insertions, 89 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 155f84253f33..a6deaa78326d 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1447,8 +1447,6 @@ rw_common:
                         return ret;
                 }
 
-                len = ret;
-
                 if (rw == WRITE)
                         file_start_write(file);
 
diff --git a/fs/read_write.c b/fs/read_write.c
index 56425cd5c9e7..933b53a375b4 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -398,11 +398,6 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
 }
 EXPORT_SYMBOL(vfs_iter_write);
 
-/*
- * rw_verify_area doesn't like huge counts. We limit
- * them to something that fits in "int" so that others
- * won't have to do range checks all the time.
- */
 int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
 {
         struct inode *inode;
@@ -429,11 +424,8 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
                 if (retval < 0)
                         return retval;
         }
-        retval = security_file_permission(file,
+        return security_file_permission(file,
                                 read_write == READ ? MAY_READ : MAY_WRITE);
-        if (retval)
-                return retval;
-        return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
 }
 
 static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
@@ -477,8 +469,9 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
                 return -EFAULT;
 
         ret = rw_verify_area(READ, file, pos, count);
-        if (ret >= 0) {
-                count = ret;
+        if (!ret) {
+                if (count > MAX_RW_COUNT)
+                        count =  MAX_RW_COUNT;
                 ret = __vfs_read(file, buf, count, pos);
                 if (ret > 0) {
                         fsnotify_access(file);
@@ -560,8 +553,9 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
                 return -EFAULT;
 
         ret = rw_verify_area(WRITE, file, pos, count);
-        if (ret >= 0) {
-                count = ret;
+        if (!ret) {
+                if (count > MAX_RW_COUNT)
+                        count =  MAX_RW_COUNT;
                 file_start_write(file);
                 ret = __vfs_write(file, buf, count, pos);
                 if (ret > 0) {
@@ -1315,7 +1309,8 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         retval = rw_verify_area(READ, in.file, &pos, count);
         if (retval < 0)
                 goto fput_in;
-        count = retval;
+        if (count > MAX_RW_COUNT)
+                count =  MAX_RW_COUNT;
 
         /*
          * Get output file, and verify that it is ok..
@@ -1333,7 +1328,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         retval = rw_verify_area(WRITE, out.file, &out_pos, count);
         if (retval < 0)
                 goto fput_out;
-        count = retval;
 
         if (!max)
                 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
@@ -1477,11 +1471,12 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
         if (flags != 0)
                 return -EINVAL;
 
-        /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT  */
         ret = rw_verify_area(READ, file_in, &pos_in, len);
-        if (ret >= 0)
-                ret = rw_verify_area(WRITE, file_out, &pos_out, len);
-        if (ret < 0)
+        if (unlikely(ret))
+                return ret;
+
+        ret = rw_verify_area(WRITE, file_out, &pos_out, len);
+        if (unlikely(ret))
                 return ret;
 
         if (!(file_in->f_mode & FMODE_READ) ||
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index ca5316e0087b..28cb4315fe57 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -99,40 +99,44 @@
 }
 
 #define iterate_and_advance(i, n, v, I, B, K) {                 \
-        size_t skip = i->iov_offset;                            \
-        if (unlikely(i->type & ITER_BVEC)) {                    \
-                const struct bio_vec *bvec;                     \
-                struct bio_vec v;                               \
-                iterate_bvec(i, n, v, bvec, skip, (B))          \
-                if (skip == bvec->bv_len) {                     \
-                        bvec++;                                 \
-                        skip = 0;                               \
-                }                                               \
-                i->nr_segs -= bvec - i->bvec;                   \
-                i->bvec = bvec;                                 \
-        } else if (unlikely(i->type & ITER_KVEC)) {             \
-                const struct kvec *kvec;                        \
-                struct kvec v;                                  \
-                iterate_kvec(i, n, v, kvec, skip, (K))          \
-                if (skip == kvec->iov_len) {                    \
-                        kvec++;                                 \
-                        skip = 0;                               \
-                }                                               \
-                i->nr_segs -= kvec - i->kvec;                   \
-                i->kvec = kvec;                                 \
-        } else {                                                \
-                const struct iovec *iov;                        \
-                struct iovec v;                                 \
-                iterate_iovec(i, n, v, iov, skip, (I))          \
-                if (skip == iov->iov_len) {                     \
-                        iov++;                                  \
-                        skip = 0;                               \
+        if (unlikely(i->count < n))                             \
+                n = i->count;                                   \
+        if (n) {                                                \
+                size_t skip = i->iov_offset;                    \
+                if (unlikely(i->type & ITER_BVEC)) {            \
+                        const struct bio_vec *bvec;             \
+                        struct bio_vec v;                       \
+                        iterate_bvec(i, n, v, bvec, skip, (B))  \
+                        if (skip == bvec->bv_len) {             \
+                                bvec++;                         \
+                                skip = 0;                       \
+                        }                                       \
+                        i->nr_segs -= bvec - i->bvec;           \
+                        i->bvec = bvec;                         \
+                } else if (unlikely(i->type & ITER_KVEC)) {     \
+                        const struct kvec *kvec;                \
+                        struct kvec v;                          \
+                        iterate_kvec(i, n, v, kvec, skip, (K))  \
+                        if (skip == kvec->iov_len) {            \
+                                kvec++;                         \
+                                skip = 0;                       \
+                        }                                       \
+                        i->nr_segs -= kvec - i->kvec;           \
+                        i->kvec = kvec;                         \
+                } else {                                        \
+                        const struct iovec *iov;                \
+                        struct iovec v;                         \
+                        iterate_iovec(i, n, v, iov, skip, (I))  \
+                        if (skip == iov->iov_len) {             \
+                                iov++;                          \
+                                skip = 0;                       \
+                        }                                       \
+                        i->nr_segs -= iov - i->iov;             \
+                        i->iov = iov;                           \
                 }                                               \
-                i->nr_segs -= iov - i->iov;                     \
-                i->iov = iov;                                   \
+                i->count -= n;                                  \
+                i->iov_offset = skip;                           \
         }                                                       \
-        i->count -= n;                                          \
-        i->iov_offset = skip;                                   \
 }
 
 static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
@@ -386,12 +390,6 @@ static void memzero_page(struct page *page, size_t offset, size_t len)
 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 {
         const char *from = addr;
-        if (unlikely(bytes > i->count))
-                bytes = i->count;
-
-        if (unlikely(!bytes))
-                return 0;
-
         iterate_and_advance(i, bytes, v,
                 __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
                                v.iov_len),
@@ -407,12 +405,6 @@ EXPORT_SYMBOL(copy_to_iter);
 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
         char *to = addr;
-        if (unlikely(bytes > i->count))
-                bytes = i->count;
-
-        if (unlikely(!bytes))
-                return 0;
-
         iterate_and_advance(i, bytes, v,
                 __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
                                  v.iov_len),
@@ -428,12 +420,6 @@ EXPORT_SYMBOL(copy_from_iter);
 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
 {
         char *to = addr;
-        if (unlikely(bytes > i->count))
-                bytes = i->count;
-
-        if (unlikely(!bytes))
-                return 0;
-
         iterate_and_advance(i, bytes, v,
                 __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
                                          v.iov_base, v.iov_len),
@@ -474,12 +460,6 @@ EXPORT_SYMBOL(copy_page_from_iter);
 
 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
 {
-        if (unlikely(bytes > i->count))
-                bytes = i->count;
-
-        if (unlikely(!bytes))
-                return 0;
-
         iterate_and_advance(i, bytes, v,
                 __clear_user(v.iov_base, v.iov_len),
                 memzero_page(v.bv_page, v.bv_offset, v.bv_len),
@@ -685,12 +665,6 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
         char *to = addr;
         __wsum sum, next;
         size_t off = 0;
-        if (unlikely(bytes > i->count))
-                bytes = i->count;
-
-        if (unlikely(!bytes))
-                return 0;
-
         sum = *csum;
         iterate_and_advance(i, bytes, v, ({
                 int err = 0;
@@ -729,12 +703,6 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
         const char *from = addr;
         __wsum sum, next;
         size_t off = 0;
-        if (unlikely(bytes > i->count))
-                bytes = i->count;
-
-        if (unlikely(!bytes))
-                return 0;
-
         sum = *csum;
         iterate_and_advance(i, bytes, v, ({
                 int err = 0;